Recommended Procedures for Testing and Evaluating Detectable Warning Systems (2010)

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29 A T T A C H M E N T Recommended Methods of Test for Evaluating Durability of Detectable Warning Systems CONTENTS Test 4-33 Durability of Detectable Warning Systems, 30 4-33-1 Freeze/Thaw Durability of Detectable Warning Systems, 38 4-33-2 High Temperature Thermal Cycling of Detectable Warning Systems, 42 4-33-3 Ultraviolet Light Exposure of Detectable Warning Systems, 49 4-33-4 Abrasion Exposure of Detectable Warning Systems, 53 4-33-5 Visual and Microscopic Evaluation of Detectable Warning Systems, 58 4-33-6 Color Measurement of Detectable Warning Systems, 66 4-33-7 Dome Shape and Geometry Measurement of Detectable Warning Systems, 72 4-33-8 Coating and Single Dome Bond in Detectable Warning Systems, 75 4-33-9 Slip Resistance of Detectable Warning Systems, 79 4-33-10 Resistance to Impact from Simulated Snowplow Blade of Detectable Warning Systems, 84 4-33-11 Resistance to Impact from Falling Tup of Detectable Warning Systems, 93 4-33-12 Wear Resistance of Detectable Warning Systems, 99 Note: The proposed test methods are the recommendations of NCHRP Project 4-33 staff at Wiss, Janney, Elstner Associates, Inc. The methods have not been approved by NCHRP or any AASHTO committee or formally accepted for AASHTO specification.

30 T4 - 33 DRAFT Recommended Method of Test for Durability of Detectable Warning Systems Designation: Draft T4 - 33 1. SCOPE 1.1. The use of d etectable warning systems at curb cuts and vehicular ways is mandated as part of the Americans with Disabilities Act. These detectable warning systems are subject to a variety of environmental conditions that can lead to material degradation and reduction in performance. In extrem e cases, degradation may occur such that the detectable warning systems become a hazard to pedestrians, for example, by becoming a tripping or slip hazard. 1.2. This method provides a protocol for testing the durability of detectable warning system s in a repeat able manner. Laboratory exposures and evaluation tests were developed to simulate the types of damage and degradation anticipated in service. Exposures are conducted cyclically to allow for effects of combined interaction of the simulated environmental exp osures. Non - destructive evaluation tests are conducted both before and after exposures to provide comparative values. Destructive evaluation tests are conducted after the exposures. 1.3. The primary objective of this test method is to provide a repeatable set of tests that can be conducted specifically to evaluate durability of detectable warning systems. Each test is suitable for use with any type of detectable warning system, regardless of the material composition or method of attach ment. Specimens are attached to concrete slabs to provide a test of the detectable warning system/sidewalk system. Data produced following this method is anticipated to be used for purposes of product comparison. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4 - 33 , Part 1 Recommended Method of Test for Freeze/Thaw Durability of Detectable Warning Systems 2.1.2. Draft T4 - 33, Part 2 Recommended Method of Test for High Temperature Thermal Cycling of Detectable Warning Systems 2.1.3. Draft T4 - 33, Part 3 Recommended Method of Test for Ultraviolet Light Exposure of Detectable Warning Systems 2.1.4. Draft T4 - 33, Part 4 Recommended Method of Test for Abrasion Exposure of Detectable Warning Systems 2.1.5. Draft T4 - 33, Part 5 Recommended Method of Test for Visual and Microscopic Evaluation of Detectable Warning Systems 2.1.6. Draft T4 - 33, Part 6 Recommended Method of Test for Color Measurement of Detectable Warning Systems

31 T4-33 DRAFT 2.1.7. Draft T4-33, Part 7 Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning Systems 2.1.8. Draft T4-33, Part 8 Recommended Method of Test for Coating and Single Dome Bond in Detectable Warning Systems 2.1.9. Draft T4-33, Part 9 Recommended Method of Test for Slip Resistance of Detectable Warning Systems 2.1.10. Draft T4-33, Part 10 Recommended Method of Test for Resistance to Impact from Simulated Snowplow Blade of Detectable Warning Systems 2.1.11. Draft T4-33, Part 11 Recommended Method of Test for Resistance to Impact from Falling Tup of Detectable Warning Systems 2.1.12. Draft T4-33, Part 12 Recommended Method of Test for Wear Resistance of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM C 192 Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory 2.2.2. ASTM C 143 Standard Test Method for Slump of Hydraulic-Cement Concrete 2.2.3. ASTM C 39 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimen 2.2.4. ASTM C 231 Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method 3. TERMINOLOGY 3.1. Cast-in-place: A detectable warning system that is cast into plastic concrete. 3.2. Surface applied: A detectable warning system that is applied to the surface of cured concrete. 3.3. Exposure regime: Test subjecting the detectable warning system specimens to simulated environmental exposure, including freeze/thaw, ultraviolet light, abrasion, and high temperature thermal cycling. 3.4. Evaluation test: Tests evaluating the performance of the detectable warning systems. These tests include visual and microscopic evaluation, dome shape and geometry measurement, slip resistance, color measurement, resistance to impact from falling tup, resistance to impact from simulated snowplow blade, wear resistance, and coating and single dome bond. 3.5. Non-destructive evaluation test: Evaluation tests that do not require any destruction of the sample. These tests are visual and microscopic evaluation, dome shape and geometry measurement, slip resistance, and color measurement.

32 T4 - 33 DRAFT 3.6. Destructive evaluation test : Evaluation tests that involve partial destruction of the sample. These tests include resistance to impact from falling tu p , resistance to impact from simulated snowplow blade , wear resistance, and coating and single dome bond . 3.7. Hot exposure category : A category indicating a set of exposure tests intended to simulate exterior environments with hot summer weather and with littl e to no freezing weather during the winter. 3.8. Cold exposure category : A category indicating a set of exposure tests intended to simulate exterior environments with slightly cooler summer weather and with freezing weather during the winter. 4. SUMMARY OF TEST METHOD 4.1. This method covers specimen fabrication, cyclic exposure, and evaluation testing of detectable warning systems for the purposes of evaluating durability. 4.2. This test method defines two exposure categories for evaluating durability : “hot” for hot weath er climates and “ cold ” for climates where lower maximum temperatures, less ultraviolet exposure and freezing occurs . This test method references three exposure regimes for the hot exposure category and four exposure regimes for the cold exposure category. Seven evaluation test methods are used for the hot exposure category, and eight evaluation test methods are used for the cold exposure category. 4.3. Exposure regimes are conducted cyclically. The specimens are cycled through high temperature thermal cycling, a brasion, freeze/thaw (for the cold exposure category) and ultraviolet light . Each exposure is conducted for one - quarter of the total duration of that particular exposure, and the specimens are rotated through the exposures for a total of four cycles. 4.4. Non - destructive evaluation tests (visual and microscopic evaluation , color measurement, dome shape and geometry measurement, and slip resistance) are conducted both before and after exposure. Destructive evaluation tests ( resistance to impact from falling tup , wear resistance, coating and single dome bond [for coated or surface - applied single dome systems] and resistance to impact from simulated snowplow blade [for the cold exposure category only]) are conducted after the exposures. 5. SIGNIFICANCE AND USE 5.1. This method covers specimen fabrication, cyclic exposure, and evaluation testing of detectable warning system s for the purposes of evaluating durability. 5.2. This test method is intended to evaluate durability of detectable warning systems that are attached to con crete slabs. 5.3. This test is intended to provide data that can be used to compare the durability of detectable warning system products. 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It i s the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

33 T4-33 DRAFT 6.2. Review the potential safety hazards associated with all of the referenced methods prior to beginning testing. 7. TEST SPECIMENS 7.1. Test specimens consist of nominally 0.6 m by 0.6 m (2 ft by 2 ft) areas of the detectable warning system applied to concrete slabs following manufacturer’s instructions. 7.2. Number of specimens 7.2.1. Two specimens of each type are required for exposure and evaluation testing. 7.2.2. If desired, an additional specimen can be fabricated for additional destructive evaluation testing of the unexposed specimen. 7.3. Detectable warning systems 7.3.1. 7.3.1.1. If the smallest available unit of detectable warning system undergoing testing is larger than this, cut the detectable warning system to produce a nominally 0.6 m by 0.6 m (2 ft by 2 ft) sample. Report the fact that the samples were cut as a deviation from the test method during each subsequent test method. Consider the potential effect of this cut on system performance when selecting domes for evaluation tests. 7.3.2. Any required method of attachment, including bolts, anchors, adhesives, or other attachment mechanisms. 7.4. Concrete Slabs 7.4.1. The specimens for use in the method shall be made in accordance with the applicable requirements of ASTM C 192. 7.4.2. 7.4.3. Note 1: It has been found to be useful to place additional reinforcing bars around the perimeter of the sample. Additional or supplementary reinforcement is optional. 7.4.4. The concrete mix shall meet the following specifications: 7.4.4.1. Contain 359 kg of Type I portland cement per m3 of concrete (605 lbs. per yd3). 7.4.4.2. Have a maximum aggregate size of 19 mm (3/4 in.) 7.4.4.3. Have a slump of 100 to 150 mm (4 to 6 in.) when tested according to ASTM C 143. Sufficient units of the detectable warning system to cover an area of slab nominally 0.6 m by 0.6 m (2 ft by 2 ft). Concrete slabs shall measure a minimum of 0.86 m by 0.86 m by 0.1 m high (34 in. by 34 in. by 4 in. high). Slabs shall be reinforced with a minimum 6x6 - W6xW6 welded wire reinforcing supported on 13 mm (1/2 in.) bolsters.

34 T4-33 DRAFT 7.4.4.4. Achieve a minimum compressive strength of 24 MPa (3500 psi) at 14 days when tested according to ASTM C 39. 7.4.4.5. Contain 5 to 8 percent entrained air when tested according to ASTM C 231. 7.4.5. The slabs shall be fabricated so that thermocouples are placed according to Draft T4-33, Part 2 Recommended Method of Test for High Temperature Thermal Cycling of Detectable Warning Systems. These thermocouples can be cast into the concrete, or can be installed after curing of the concrete. Note 2: It has been found useful to cast lifting inserts into the concrete slabs near the edges to facilitate moving the slabs during the testing process. 7.5. For cast-in-place detectable warning systems: 7.5.1. Fill an appropriately sized form with concrete, strike-off the surface, consolidate with a hand vibrator, finish to an even surface with floats, and set the detectable warning system in the concrete according to manufacturer’s instructions while the concrete is still plastic. 7.5.2. Center the detectable warning system in the form, leaving a uniform concrete border on all sides of the detectable warning system. 7.5.3. Edge finish around the perimeter of the form. 7.5.4. Do not edge finish around the perimeter of the detectable warning system. 7.5.5. The final finish shall be done with a wooden float, leaving an even surface. Steel trowels shall not be permitted. After the water sheen has disappeared, the surface shall be given a final finish by brushing with a whitewash brush. 7.5.6. Moist cure the concrete according to ASTM C 192 for a minimum of 14 days. 7.5.7. Provide a unique marking to the slab for future identification. 7.6. For surface-applied detectable warning systems: 7.6.1. Fill an appropriately sized form with concrete, strike-off the surface, consolidate with a hand vibrator, and finish to an even surface with floats. 7.6.2. Finish the concrete in the area to receive the detectable warning system as directed by the manufacturer’s instructions. 7.6.3. Moist cure the concrete according to ASTM C 192 for a minimum of 14 days. 7.6.4. Apply the detectable warning system to the cured concrete slabs according to the manufacturer’s instructions. 7.6.5. Provide a unique marking to the slab for future identification. Note 3: A permanent ink marker has been found suitable for providing markings on the specimens. It is recommended that both the top surface and side of the detectable warning system specimen be marked.

35 T4 - 33 DRAFT 8. APPARATUS 8.1. The apparatus required for each test is described in the referenced methods. 9. CALIBRATION 9.1. Any calibration required for each test is described in the referenced method. 10. PROCEDURE 10.1. P erform non - destructive evaluation on each of the detectable warning system specimen s according to: 10.1.1. Draft T4 - 33, Part 5 Recommended Method of Test for Visual and Microscopic Evaluation of Detectable Warning System s . 10.1.2. Draft T4 - 33, Part 6 Recommended Method of Test for Color Measurement of Detectable Warning System s . 10.1.3. Draft T4 - 33, Par t 7 Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning System s . 10.1.4. Draft T4 - 33, Part 9 Recommended Method of Test for Slip Resistance of Detectable Warning System s. 10.2. Subject two specimens of each type to the exposure regimes . Table 1 . Exposure duration for each exposure category . Exposure Regime Hot Exposure Category Cold Exposure Category Freeze/Thaw (None) 60 cycles High Temperature Thermal Cycling 60 cycles 25 – 93ºC black panel temp . (77 – 200°F) 60 cycles 25 – 77ºC black panel temp . (77 – 170°F) Ultraviolet Light Exposure 1500 hrs 1000 hrs Abrasion Exposure 16 passes 16 passes 10.3. Determine if the samples are to be exposed to the hot exposure category or the cold exposure category. 10.4. For exposures in the hot exposure category: 10.4.1. Subject the specimens to 15 thermal cycles with the maximum temperature defined by a n insulated black panel temperature of 93°C (200°F) according to Draft T4 - 33, Part 2 Recommended Method of Test for High Temperature Thermal Cycling of Detectable Warning 10.4.2. Subject the specimens to four abrasion cycles according to Draft T4-33, Part 4 Recommended Method of Test for Abrasion Exposure of Detectable Warning Systems. Systems.

36 T4-33 DRAFT 10.4.3. Subject the specimens to 375 hours of ultraviolet radiation exposure according to Draft T4-33, Part 3 Recommended Method of Test for Ultraviolet Light Exposure of Detectable Warning Systems. 10.4.4. Repeat the series of exposures, in the same order, three additional times for a total of four cycles. This will provide a total of 60 thermal cycles, 16 abrasion cycles, and 1500 hours of ultraviolet radiation. 10.5. For exposures in the cold exposure category: 10.5.1. Subject the specimens to 15 thermal cycles with the maximum temperature defined by an insulated black panel temperature of 77°C (170°F) according to Draft T4-33, Part 2 Recommended Method of Test for High Temperature Thermal Cycling of Detectable Warning Systems. 10.5.2. Subject the specimens to four abrasion cycles according to Draft T4 - 33, Part 4 Recommended Meth od of Test for Abrasion Exposure of Detectable Warning System s. 10.5.3. Subject the specimens to 15 freeze/thaw cycles according to Draft T4 - 33, Part 1 Recommended Method of Test for Freeze/Thaw Durability of Detectable Warning Systems . 10.5.4. Subject the specimens to 25 0 hours of ultraviolet radiation exposure according to Draft T4 - 33, Part 3 Recommended Method of Test for Ultraviolet Light Exposure of Detectable Warning Systems . 10.5.5. Repeat the series of exposures, in the same order, three additional times for a total of four cycles. This will provide a total of 60 thermal cycles, 16 abrasion cycles, 60 freeze/thaw cycles and 10 00 hours of ultraviolet radiation. 10.6. After completion of the cyclic exposures, perform non - destructive evaluation tests on each specim en according to: 10.6.1. Draft T4 - 33, Part 5 Recommended Method of Test for Visual and Microscopic Evaluation of Detectable Warning System s. 10.6.2. Draft T4 - 33, Part 6 Recommended Method of Test for Color Measurement of Detectable Warning System s. 10.6.3. Draft T4 - 33, Part 7 Re commended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning System s. 10.6.4. Draft T4 - 33, Part 9 Recommended Method of Test for Slip Resistance of Detectable Warning System s. 10.7. After completion of the non - destructive evaluation tests, perform the destructive evaluatio n tests on either of the exposed detectable warning system specimens. If there are discrepancies in the response of the two samples to the exposure, identify those discrepancies when report ing the results of the evaluation tests. The referenced test methods are: 10.7.1. Draft T4 - 33, Part 11 Recommended Method of Test for Resistance to Impact from Falling Tup of Detectable Warning Systems .

37 10.7.2. Draft T4 - 33, Part 12 Recommended Method of Test for Wear Resistance of Detectable Warning Syste ms . 10.7.3. If the s pecimens were tested according to the cold exposure category, test for snowplow resistance according to: Draft T4 - 33, Part 10 Recommended Method of Test for Resistance to Impact from Simulated Snowplow Blade of Detectable Warning Systems . 10.7.4. If the system is coated or contains surface - applied single domes, perform testing according to Draft T4 - 33, Part 8 Recommended Method of Test for Coating and Single Dome Bond in Detectable Warning Systems . Note 4 : There may be insufficient sample on one s pecimen to complete all of the destructive tests, and portions of both specimens may be consumed by the destructive testing. 11. REPORT 11.1. The report shall include the following: 11.1.1. Type, manufacturer, and , if known, lot number of the detectable warning system(s) tested. 11.1.2. T he exposure category (hot or cold ) . 11.1.3. T he results from each exposure and evaluation test according to the referenced method. 11.1.4. A ny deviations from this method. 12. PRECISION 12.1. Data not available at t his time. T4-33 DRAFT

38 T4-33 DRAFT Recommended Method of Test for Freeze/Thaw Durability of Detectable Warning Systems Designation: Draft T4-33, Part 1 1. SCOPE 1.1. This method covers the exposure of detectable warning/concrete systems to repeated cycles of freezing and thawing in the laboratory. 1.2. This exposure is intended to be conducted as part of the test protocol outlined in Draft T4-33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 3. SUMMARY OF TEST METHOD 3.1. This method exposes detectable warning systems that have been cast into or applied to concrete to repetitive cycles of freezing and thawing temperatures. Freezing and thawing is carried out with the samples fully submerged in a sodium chloride solution. 4. SIGNIFICANCE AND USE 4.1. This test method is intended to aid in the evaluation of freeze/thaw durability of detectable warning systems that are cast into concrete. 4.2. This method is intended to be used as part of the Draft T4-33 to evaluate the durability of detectable warning systems. An evaluation test is not included in this method. 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 6. TEST SPECIMENS 6.1. Test specimens prepared in accordance with Draft T4-33 are required. 7. APPARATUS 7.1. A chamber that is capable of maintaining sufficiently low temperatures to freeze the deicer salt solution.

39 T4-33 DRAFT 7.1.1. If a constant-temperature freezer is used, the specimens can be removed and allowed to thaw at room temperature. 7.1.2. A thermal cycling chamber capable of both freezing and thawing the sodium chloride solution may also be used. 7.2. Containers, fabricated out of a corrosion-resistant material, such as plastic or stainless steel, and strong enough to support the specimens submerged in sodium chloride solution. The containers may also be made out of wood with a watertight liner made of rubber or other material. 7.2.1. The containers should be sized to fit the length and width of the specimens with little additional room to reduce the amount of solution that must occupy that space. The depth of the container should be at least 2 cm (0.75 in.) higher than the tops of the domes to accommodate the solution on top of the specimen. Note 1: For 86 cm by 86 cm by 10 cm (34 in. by 34 in. by 4 in.) specimens, containers with interior dimensions of 90 cm by 90 cm by no less than 12 cm (35.4 in. by 35.4 in. by 4.75 in.) are suitable. 7.2.2. The containers should be fitted with lids of a corrosion-resistant material. 7.3. Thermocouples and a thermocouple logger, if desired, to monitor the temperature of the solution and the samples. While useful for tracking test performance, the use of thermocouples is optional. Note that if used, thermocouples will generally need to be installed in the concrete samples when originally fabricated. 8. REAGENTS 8.1. Deicer salt solution (3% sodium chloride solution) 8.1.1. Reagent water 8.1.2. Sodium chloride, 99% or higher purity Note 2: If desired, an alternate deicer solution, which will cause scaling on susceptible concrete may be substituted for the 3% sodium chloride solution. 9. PROCEDURE 9.1. The specimens should be placed in the containers with the detectable warning system side up. 9.1.1. If a watertight liner is used, make sure the liner is in place and damage-free prior to inserting the specimen. 9.2. Fill the specimen containers with solution until the level of the liquid is above the tops of the domes. Additional solution may be added, but will increase the freezing and thawing time of the specimens. Note 3: Check the specimen containers for leaks while adding solution. If leaks are apparent, repair as appropriate.

40 T4-33 DRAFT 9.2.1. Place lids on the containers to reduce evaporation of the solution once the solution is at the appropriate level. Note 4: Solution may be added prior to placing the specimens in the freezing chamber, or after the specimens are in the chamber. If adding solution after placing the specimens in the freezing chamber, check for leaks first to avoid having to remove specimens if leaks become apparent upon filling the containers with solution. 9.3. Place the specimens in the freezing chamber, ensuring that enough room is left above the specimen to view and access the solution in order to confirm that freezing and thawing is taking place. Adjust the temperature and duration of the freezing cycle to produce complete freezing of the solution in all specimens. Do not cool the air temperature in the chamber below -23ºC (-10°F). 9.3.1. Ensure the test solution is completely frozen for at least 30 minutes during each freezing cycle. Confirm freezing of solution on all specimens by visually and tactilely monitoring the solution or by remote monitoring of thermocouples placed in the solution. 9.4. Adjust the temperature and duration of the thawing cycle to confirm complete thawing of the solution in all specimens. Do not heat the air temperature in the chamber above 29ºC (85°F). 9.4.1. Ensure the test solution is completely thawed for a minimum of 30 minutes. Confirm thawing of solution on all specimens by visually and tactilely monitoring the solution or by remote monitoring of thermocouples placed in the solution. 9.5. Periodically monitor the solution level and ensure that the tops of the domes remain submerged in 3% sodium chloride solution. Note 5: If the solution level has decreased, ascertain if the level has dropped because of evaporation or a leak. If the cause of liquid level drop is a leak, fill the specimen containers with 3% sodium chloride solution to cover the tops of the domes. If the cause of the liquid level drop is evaporation, fill the specimen containers with reagent water to cover the tops of the domes. 9.6. The length of a complete freeze-thaw cycle shall be no less than 6 hours. 9.7. Cycle the specimens for the desired number of cycles according to the Draft T4-33. 10. REPORT 10.1. The report shall include the following: 10.1.1. The sample identification assigned according to the Draft T4-33. 10.1.2. Type, manufacturer, and, if known, lot number of the detectable warning system(s) tested. 10.1.3. Air temperatures achieved in the freezing and/or thawing chambers. 10.1.4. The duration of complete freeze and thaw and the method by which freezing and thawing was confirmed. 10.1.5. The number of cycles.

41 T4-33 DRAFT 10.1.6. Any deviation from the procedures outlined in this method, such as if an alternative salt was used to produce the solution. 11. PRECISION 11.1. Data not available at this time.

42 T4-33 DRAFT Recommended Method of Test for High Temperature Thermal Cycling of Detectable Warning Systems Designation: Draft T4-33, Part 2 1. SCOPE 1.1. This method covers the exposure of detectable warning systems to alternating heating and cooling cycles in the laboratory. Thermal excursions have the potential to induce stresses between the detectable warning system and the substrate, which may have different coefficients of thermal expansion. This thermal cycling may be rapid, such as due to sudden rainfalls, or more gradual due to daily variations in ambient temperature. 1.2. This exposure is intended to be conducted as part of the test protocol outlined in Draft T4-33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM G 151-06, Standard Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources. 3. SUMMARY OF TEST METHOD 3.1. This method exposes detectable warning systems to cyclic ramped heating and sudden cooling to simulate daily thermal variations and rapid cooling events. 4. SIGNIFICANCE AND USE 4.1. This exposure method is intended to produce repetitive elevated temperature excursions followed by rapid water cooling to produce accelerated weathering of detectable warning systems. 4.2. This method is intended to be used as part of the Draft T4-33 to evaluate the durability of detectable warning systems. An evaluation test is not included in this method. 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

43 T4-33 DRAFT 6. TEST SPECIMENS 6.1. Test specimens prepared in accordance with Draft T4-33 are required with the modification described below. 6.2. Thermocouples shall be embedded at the following locations in the specimen: 6.2.1. Near surface (Thermocouples A, B in Figure 1) 6.2.1.1. For detectable warning systems with a minimum thickness less than 6 mm (¼ in.), embed thermocouples at the middle and corner of the specimen at the interface between the concrete and the detectable warning system. These thermocouples should be installed at the time of system installation or concrete casting. 6.2.1.2. For all other detectable warning systems, install thermocouples at 6 mm (¼ in.) below the field of the detectable warning sample. To install, drill a hole for the thermocouple and adhere it to the specimen with thermally conductive epoxy. 6.2.2. Interior middle (Thermocouple C in Figure 1): Install thermocouple 51 mm (2 in.) from the top surface of the concrete in the middle of the specimen, when viewed in plan. For most specimens, this will be in the mid-height of the concrete slab. 7. APPARATUS 7.1. An infrared electric heater shall be used to heat the detectable warning system with a control system capable of performing “ramp” (temperature increase over time) and “soak” (constant temperature over time) steps. Note 1: 3.2 kW (11,000 Btu/hr) electric infrared heaters with quartz tubes have been used successfully to provide the required amount of heat to the sample surface. 7.2. An enclosure capable of surrounding one detectable warning system test specimen shall be used to control the environment around the test specimen. The enclosure is open on the bottom but enclosed on all other sides. The specimen shall be inclined at a 1:10 slope to allow for water to flow off the surface. The sides of the enclosure shall be constructed with 25 mm (1 in.) thick rigid insulation with foil backing. The insulation shall be oriented with the reflective foil backing toward the interior. Note 2: An enclosure that is 1.2 m by 1.2 m by 1.2 m (48 in. by 48 in. by 48 in.) has been used successfully to house the detectable warning system, heating, and water distribution/cooling apparatus. 7.3. The specimen shall be cooled by water, applied from one edge in a steady stream at a flow rate of 10 to 20 L/min (3 to 6 gal/min). The water shall uniformly cover the surface and drain off the edge of the specimen without pooling. The temperature of the cooling water shall be 10–20°C (50–68°F). Note 3: A 19 mm (¾ in.) diameter pipe with 6 mm (¼ in.) diameter holes, spaced at 75 mm (3 in.) on center has been used successfully to provide a uniform application of water.

44 T4 - 33 DRAFT 7.4. Temperature measurements on the surface of the specimen shall be made at two locations using insulated black panel thermometers, constructed according to the requirements in ASTM G 151 - 06, Annex A2. N ote 4: Measured black panel temperature s are generally expected to be greater than the specimen surface temperature. Note 5: Photographs of a system consistent with these requirements are given in the appendix of this method. 8. CALIBRATION 8.1. Record the water t emperature at the beginning of each set of test cycles and adjust as necessary to meet the requirements of Section 9.2 . 4 . 8.2. Adjust the water pressure so that the water lands on one edge of the specimen and flows across the entire surface . The discharge rate should meet the requirements of Section 7.3 and be such that significant splashing does not occur. 8.3. The uniformity of the infrared radiation on the surface of the specim en shall be measured as follows: 8.3.1. Heat the specimen until the temperature measured by the center black panel thermometer is the maximum cycle temperature and stable temperature s are achieved. 8.3.2. Assure that the steady state reading for the second black panel thermometer on any part of the detectable warning system i s no more than 2 0 ° C ( 36 ° F ) less than the center black panel thermometer reading. 8.4. The heat flux at the surface shall be capable of raising the black panel thermometer from ambient temperature to the maximum cycle temperature in less than 15 minutes. 8.5. Ad just the distance from heat source , spacing of heating elements , or number of heating elements in the enclosure to meet the requirements in Section 8.4 . 9. PROCEDURE 9.1. Monitoring 9.1.1. Place two insulated black panel thermometers on the specimen at the following locations: 1. At the geometric center of the detectable warning system 2. At the corner of the detectable warning surface, such that the edges of the thermometer are 25 mm (1 in.) from either edge of the detectable warning 9.1.2. Record the maximum and minimum t emperature measured by the center and corner black panel thermometers each cycle. 9.1.3. Record the maximum and minimum temperature of all thermocouples each cycle. 9.2. Thermal Cycle 9.2.1. Initialization : Apply water to the specimen for 15 minutes prior to the first cycle.

45 T4-33 DRAFT 9.2.2. Ramp: Discontinue water flow and apply heat to increase the temperature of the center black panel thermometer to the maximum temperature specified in Draft T4-33 in less than 15 minutes. 9.2.3. Soak: Maintain the temperature of the center black panel thermometer at the specified temperature ±2°C (± 4°F) for 2 hours. 9.2.4. Cool: Apply water to the specimen until the temperature of the “interior middle” thermocouple (Thermocouple C) reaches 25°C (77°F). 9.2.5. One cycle is defined as a completion of the ramp, soak, and cool steps described above. Repeat as required in the Draft T4-33. Note 6: A schematic of a thermal cycle consistent with these requirements is given in the appendix of this method. Note 7: As an alternative to controlling the duration of cooling based on continuous monitoring of the temperature at the “interior middle” thermocouple (Thermocouple C), the required duration for the cooling step may be established during the first few cycles at the beginning of testing for a specific detectable warning system and then this duration must be repeated consistently. 10. REPORT 10.1. The report shall include the following: 10.1.1. The sample identification assigned according to the Draft T4-33. 10.1.2. Type, manufacturer, and, if known, lot number of the detectable warning system(s) tested. 10.1.3. The number of cycles performed. 10.1.4. The temperature of the water used for cooling. 10.1.5. The recorded minimum and maximum thermocouple readings for each cycle. 10.1.6. The recorded minimum and maximum black panel thermometer readings for each cycle. 10.1.7. Any deviations from the test procedure outlined herein. 11. PRECISION 11.1. Data not available at this time.

46 T4 - 33 DRAFT Figure 1. Thermocouple Layout

47 T4-33 DRAFT APPENDIX (Non-mandatory Information) Figure 2. Enclosure and sample under heating (ramp) portion of test cycle. Figure 3. Enclosure and sample under cooling portion of test cycle. Note the sheet of water draining to the left on the sample surface.

48 T4 - 33 DRAFT Figure 4 . Insulated black panel thermometer used for surface temperature evaluation. Figure 5. Schematic of Thermal Cycles. Interior is temperature measured by “interior middle” thermocouple. Te m pe ra tu re Time Black Panel (center) Black Panel (corner) Near surface (center) Near surface (corner) Interior Initialization Ramp Soak Cool

49 T4-33 DRAFT Recommended Method of Test for Ultraviolet Light Exposure of Detectable Warning Systems Designation: Draft T4-33, Part 3 1. SCOPE 1.1. This method covers the exposure of detectable warning systems to ultraviolet light. This exposure has the potential to fade pigments and/or deteriorate the material substrate. Fading or change in color or contrast over time may reduce the Americans with Disabilities Act Accessibility Guidelines–required visual contrast between the system and surrounding concrete. 1.2. This exposure is intended to be conducted as part of the test protocol outlined in Draft T4-33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM G 151-06, Standard Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources 2.2.2. ASTM G 154-06, Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test 3. TERMINOLOGY 3.1. Irradiance: a measure of power flux. For this method, irradiance is measured over a narrow bandwidth of the peak wavelength for the ultraviolet lights used. 4. SUMMARY OF TEST METHOD 4.1. The ultraviolet (UV) weathering test is a modification of ASTM G 151-06 and ASTM G 154-06. As modified, this test uses a set of ultraviolet lights, analogous to those described in ASTM G 154-06, designed to produce radiation primarily in the UVA part of the solar spectrum. 5. SIGNIFICANCE AND USE 5.1. This exposure method is intended to produce accelerated weathering of detectable warning systems cast into concrete. 5.2. This method is intended to be used as part of the Draft T4-33 to evaluate the durability of detectable warning systems. An evaluation test is not included in this method.

50 T4-33 DRAFT 6. SAFETY HAZARDS 6.1. The ultraviolet lights used in this exposure produce wavelengths at intensities that are capable of damaging eye and skin tissue. Adequate protection should be used when lamps are in operation. 6.2. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4-33 are required. 8. APPARATUS 8.1. Radiometer 8.2. Peak irradiance—The radiometer used shall be capable of measuring electromagnetic radiation at a peak wavelength of 340 nm. 8.2.1. Maximum bandwidth—The maximum allowable bandwidth of the detector shall be 10 nm, centered about the peak irradiance. 8.2.2. Range and precision—The detector shall be capable of measuring flux in a range from 0 to 2 W/m2/nm with a precision of 0.01 W/m2/nm. 8.3. UV Tent 8.3.1. Description—The UV tent is an enclosure that is capable of holding multiple fluorescent ultraviolet light fixtures in a plane at a fixed distance from and parallel to the surface of the detectable warning system. The tent may be constructed such that multiple samples are placed under one enclosure. The enclosure is required to protect personnel from exposure to the ultraviolet radiation. 8.3.2. Irradiance requirements—By adjusting the distance of the sample surface from the lights, the number of fluorescent lights, or the voltage, the peak irradiance at any point on the surface of the detectable warning system shall be 0.6 W/m2/nm ± 0.02 W/m2/nm. The minimum irradiance at any point on the detectable warning system shall be no less than 70% of the peak irradiance. If the radiance is between 70% and 90% at any point on the specimen surface, specimens shall be rotated four times per exposure cycle. If the irradiance at all points on the specimen is greater than 90% of the peak irradiance, periodic repositioning is recommended but not required. 8.3.3. Materials—The tent may be made of any material but should have an interior surface that reflects at least 50% of radiation at the peak wavelength. 8.3.4. Temperature—The air temperature at the surface of the specimens shall be measured. Maintain temperatures in the chamber at 30 ± 3ºC (86 ± 5ºF). 8.4. Ultraviolet Light Source

51 T4-33 DRAFT 8.4.1. The ultraviolet source used shall be UVA-340 lamps, as described in ASTM G 154-06. 9. CALIBRATION 9.1. Instrumentation 9.1.1. The radiometer used for measurement shall be calibrated and traceable to national standards. 9.1.2. The temperature gauge used for measurement shall be calibrated and traceable to national standards. 9.2. Irradiation 9.2.1. Before each testing cycle, calibrate the irradiance at the level of the testing surface. 9.2.2. Find the peak irradiance and the minimum irradiance in the same area that the detectable warning system will be placed. 9.2.3. Adjust the distance from lights, spacing of lights, or number of lights in the enclosure so that the maximum and minimum irradiance meet the requirements in Section 8.3.2. 10. PROCEDURE 10.1. Monitoring 10.1.1. Place a temperature gauge and radiometer at the same level as the detectable warning system. Do not block any surface of the detectable warning system with the instruments. 10.1.2. During the interval of the exposure, record at least one irradiance and temperature measurement daily. Measurements shall be taken at the same location for comparison purposes. Be sure to record daily temperature and irradiance before the enclosure is opened for any reason. 10.2. Exposure 10.2.1. Place the detectable warning/concrete system sample or samples to be tested underneath the enclosure tent. 10.2.2. Irradiate the specimen continuously for the number of hours specified in Draft T4-33. 11. REPORT 11.1. Report the sample identification assigned according to the Draft T4-33. 11.2. Report type, manufacturer, and, if known, lot number of the detectable warning system(s) tested 11.3. Report the duration of exposure in hours. Do not include time when the UV lamps were off for maintenance or observations. 11.4. Report the daily radiometer and temperature readings for the duration of the exposure.

52 T4-33 DRAFT 12. PRECISION 12.1. Data not available at this time.

53 T4-33 DRAFT Recommended Method of Test for Abrasion Exposure of Detectable Warning Systems Designation: Draft T4-33, Part 4 1. SCOPE 1.1. This method covers the exposure of detectable warning/concrete systems to repeated cycles of abrasion in the laboratory. Abrasion is expected to occur primarily as a result of pedestrian traffic over the walking surface. Dirt, debris, and sand used to provide traction in an icy environment is anticipated to accelerate the abrasion. Note that this abrasion exposure is distinguished from the procedure outlined in Draft T4-33, Part 12 Recommended Method of Test for Wear Resistance of Detectable Warning Systems in that the severity of the abrasion action is reduced and applied to the full surface of the detectable warning system. 1.2. This exposure is intended to be conducted as part of the test protocol outlined in Draft T4-33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM D 1056 Standard Specification for Flexible Cellular Materials—Sponge or Expanded Rubber 3. SUMMARY OF TEST METHOD 3.1. This method describes an exposure regime where the surface of a detectable warning system that has been cast into or applied to concrete is abraded by an abrasive pad mounted on a sled of known weight and resilience. This sled is translated across the surface of the sample multiple times as part of each exposure cycle. 4. SIGNIFICANCE AND USE 4.1. The sled and abrasive have been defined to simulate the wear that may be expected from pedestrian traffic. 4.2. This method is intended to be used as part of the Draft T4-33 to evaluate the durability of detectable warning systems. An evaluation test is not included in this method.

54 T4 - 33 DRAFT 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 6. TEST SPECIMENS 6.1. Two t es t specimens prepared in accordance with Draft T4 - 33 are required. 7. APPARATUS 7.1. Abrasive Sled — The abrasive action will be applied to the surface of the detectable warning system by a sled (Figure 1) . This sled shall consist of abrasive paper mounted to the bot tom of a plate assembly made up of a top plate of rigid material and a securely attached layer of compressible rubber foam. The area of the foam to which the paper will be attached shall be 15.2 x 30.5 ± 0.25 cm [6 x 12 ± 0.1 in.]. The rigid p late shall be 20.3 ± 0.25 cm [8 ± 0.1 in.] in width. The paper shall be wrapped to the top of the rigid plate creating an angle of slope 3/8:1. The total weight of the sled will be 6 ± 0.05 kg [13.2 ± 0.1 lbs.] Figure 1. Abrasive Sled Note 1 : Photographs of a system consistent with the requirements of this method are given in the a ppendix to this method. 7.1.1. The 0.95 cm (3/8 in.) thick, compressible rubber foam layer shall conform with the following specifications: The material shall be c losed - cell f oam r ubber with a durometer of 40 ± 10 OO Shore and d ensity of 0.064 – 0.128 g/cm 3 [ 4 – 8 lbs./cu. ft .] and shall comply with ASTM D 1056 Grade 2A . Firmness expressed by compression - deflection test of 25% deflection shall be 13.8 –

55 T4-33 DRAFT 34.5 kPa [2–5 psi]. (Blended Neoprene/EPDM/SBR foam has been found to meet these requirements.) 7.1.2. The abrasive paper shall be 120-grit, C weight abrasive paper with a non-loading agent. The paper shall conform with the following specifications: The paper backing shall be abrasive grade and weigh 120 ± 5 g/m2. The adhesive shall be urea-formaldehyde resin. The total adhesive coat weight (combined make and size coat) shall be 118 ± 5 g/m2. The abrasive shall be 120-grit FEPA graded coated abrasive grade, low titania, heat treated aluminum oxide. The abrasive coat weight shall be 120 ± 5 g/m2. A zinc stearate non-loading agent shall be applied at density not to exceed 20 g/m2. Note 2: 120-grit Gold Non-Loading C weight abrasive paper available from Johnson Abrasives, Inc., 49 Fitzgerald Drive, Jaffrey, NH 03452, conforms with these requirements. 7.2. A translation mechanism capable of repeatedly moving the sled across the detectable warning system surface shall be used. This system shall apply a force parallel to the detectable warning system surface in such a manner that the movement is continuous and without chatter. The full width of the abrasive surface shall extend past the last row of domes. Note 3: A test translation mechanism conforming with the requirements of this method is pictured in the appendix. It consists of a frame supporting a hand-activated pulley system that translates the abrasive sled across the sample surface. 8. PROCEDURE 8.1. The full area of the detectable warning surface will be exposed to the abrasion process. One half of the surface will be abraded at a time. Designate the sides as “A” and “B” or similar. Record which side is abraded first during each cycle, and alternate which side is abraded first at the start of the next run. 8.2. Inspect the apparatus for signs of wear or damage. If wear or deformation in the compressible foam is observed, install new foam. Install fresh abrasive paper at the start of each test. 8.3. Measure the height of the domes at four previously selected areas according to the method outlined in Draft T4-33, Part 7 Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning Systems. Two of the four measurements should be on each side of the test surface. 8.4. Place the translation mechanism over the detectable warning sample taking care that the sled will cover one half of the tested surface. 8.5. Cycle the specimens for the desired number of cycles according to the Draft T4-33. A single complete cycle will be defined as the distance covered when the sled moves from and back to its starting position. 8.6. Reposition the translation mechanism and repeat the cycling on the second half of the tested surface. 8.7. Repeat the measurement of the height of the selected domes according to the method outlined in Draft T4-33, Part 7 Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning Systems.

56 T4-33 DRAFT 9. REPORT 9.1. Report the sample identification assigned according to the Draft T4-33. 9.2. Report type, manufacturer, and, if known, lot number of the detectable warning system(s) tested. 9.3. Report the number of cycles. 9.4. Report the change in height of each of the selected domes. 9.5. Report any deviation from the procedures outlined in this method. 10. PRECISION 10.1. Data not available at this time.

57 T4-33 DRAFT APPENDIX (Non-mandatory Information) Figure 1-- A frame supporting a hand-activated wire and pulley system that translates the abrasive sled across the sample surface (top) and close-up of side of abrasive sled showing rigid top plate, compressible foam and abrasive paper (bottom).

58 T4 - 33 DRAFT Recommended Method of Test for Visual and Microscopic Evaluation of Detectable Warning Systems Designation: Draft T4 - 33, Part 5 1. SCOPE 1.1. This test method covers visual and microscopic evaluation of detectable warning systems. Visual and microscopic evaluation provide a method to determine the effects of exposure on detectable warning system specimens that are not readily measured with other standard tests. 1.2. This e valuation test is inte nded to be conducted as part of the test protocol outlined in Draft T4 - 33 , which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4 - 33 Recommended Method of Test for Durability of Detectable Warning Systems 3. TERMINOLOGY 3.1. Dome: The truncated dome on the detectable warning system . 3.2. Field: The space between the domes on the detectable warning system . The field is level with the surrounding concrete. 4. SUMMAR Y OF TEST METHOD 4.1. This test method describes how to conduct a visual and microscopic evaluation of detectable warning systems in conjunction with exposures described in Draft T4 - 33 . 5. SIGNIFICANCE AND USE 5.1. Visual and microscopic evaluation provide s a means to evaluate any degradation of a detectable warning system as a result of laboratory exposures. Visual and microscopic evaluation is intended to be carried out prior to exposure testing and upon completion of the exposure testing, prior to any fur ther evaluation. 5.2. This test method is in tended to be used as part of Draft T4 - 33 to evaluate the durability of detectable warning systems. 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

59 T4 - 33 DRAFT 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4 - 33 are required. 8. APPARATUS 8.1. A hand lens or portable microscope, capable of magnifications of 10 X to 30 X . 9. PROCEDURE 9.1. Visually examine each specimen for any defects or unusual features, which may include cracks, dents, divots, discolorations, or other features. Also examine the specimens for irregularities in the attachment of the specimen to the concrete, such as debonding or displacement of the detectable warning system . Some features may not be apparent on an unexposed specimen, but may become apparent as a result of the test exposures. 9.1.1. Examine the overall specimen from a sufficient distance to observe the entire specimen at once. 9.1.2. Examine the specimen from a distance of 15 to 45 cm (6 to 1 8 in.) from several angles to ensure that all features are obse rved. 9.2. Identify observed features with a contrasting marker and document the locations for future reference. 9.3. Photograph the sample. Take one overall photograph of the sample and the concrete. Additional close - up photographs of any particular features that are observed are recommended . 9.4. Select two areas, approximately 2.5 cm by 2.5 cm (1 in. by 1 in.) in area, for microscopic examination. Examine these areas with a hand lens or microscope, with magnifications 10X to 30X . 9.4.1. If possible , record a micrograph of each area for future reference. 9.4.2. Document the areas examined in the project notes and record any observations. Note 1: For some materials systems, applying dye or ink to the areas examined, then rapidly removing excess from the surface , is a good way to hig hlight microcracks and other surface features. Note 2: If multiple people will be carrying out the visual and microscopic examinations, it is helpful if all observers conduct examinations together on at least one sample and compare their observations to ensure that similar results are produced. 10. REPORT 10.1. Report the following: 10.1.1. Exposure level, if any, prior to the visual and microscopic examination. 10.1.2. Description of features observed visually and location on the specimen.

60 T4 - 33 DRAFT 10.1.3. Description of features observed microsc opically and location on the specimen. 10.1.4. Any changes from prior evaluations of the same specimen, if applicable. 11. PRECISION 11.1. Data not available at this time.

61 T4 - 33 DRAFT APPENDIX (Non - mandatory Information) Several types of degradation have been observed visually and microscopically as a result of exposure testing of detectable warning systems. The particular type of degradation depends on several factors, including the de tectable warning system material , the mechanism of attachment to the concrete, and the geometry of the system. It is anticipated that detectable warning system products may exhibit a variety of or no degradation types and that the type of degradation will depend on the exposure. The following types of degradation have been observed. This list is intended as an aid to the researcher, and is not comprehensive or representative of any particular detectable warning system. • Macrocracking (detected visually), often near the edges of specimens or near the domes. • Microcracking (detected microscopically), on both the domes and the field. These cracks are too short to be detected visually. • Debonding of the detectable warning syst em from the concrete. • Displacement of the detectable warning system relative to the concrete. • Fracturing or breaking of domes. • Decrease in dome height (also measured according to Draft T4 - 33, Part 7 Recommended Method of Test for Dome Shape and Geometry Me asurement of Detectable Warning Systems ). • Change in surface texture of the field or domes. • Change in color (also measured according to Draft T4 - 33, Part 6 Recommended Method of Test for Color Measurement of Detectable Warning Systems ). Photographs of some types of degradation are provided in Figures 1 through 7.

62 T4 - 33 DRAFT Figure 1 - Macrocracks around the perimeter of a detectable warning system. Figure 2 - Macrocracks around the edges of domes on a detectable warning system.

63 T4 - 33 DRAFT Figure 3 - Loss of d ome height of a detectable warning system. Figure 4 - Loss of dome height of a detectable warning system.

64 T4 - 33 DRAFT Figure 5 - Relative displacement of a detectable warning system, caused by freeze jacking. Figure 6 - Micrograph of surface features of a detectable warning system.

65 T4 - 33 DRAFT Figure 7 - Micrograph of surface features of a detectable warning system, with microcracking.

66 T4-33 DRAFT Recommended Method of Test for Color Measurement of Detectable Warning Systems Designation: Draft T4-33, Part 6 1. SCOPE 1.1. This test method covers the measurement of color and color change of detectable warning systems. Exposure to environmental conditions, such as ultraviolet light and abrasion, may fade the color of the detectable warning system. 1.2. The Americans with Disabilities Act Accessibility Guidelines discuss the need for color contrast between the detectable warning system and the surrounding pavement. Certain materials may experience color fading or color change upon exposure to the environment. Measurement of color and evaluation of color change is used as a tool to evaluate potential changes in color contrast of the detectable warning system and surrounding pavement. 1.3. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 3. TERMINOLOGY 3.1. Dome: The truncated dome on the detectable warning system. 3.2. Field: The space between the domes on the detectable warning system. The field is level with the surrounding concrete. 4. SUMMARY OF TEST METHOD 4.1. This method describes the measurement of color of detectable warning systems and the calculation of color difference after exposure. 5. SIGNIFICANCE AND USE 5.1. This test method is intended to evaluate color and color change of detectable warning systems that are cast into concrete. 5.2. This method is intended to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems.

67 T4-33 DRAFT 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4-33 are required. 8. APPARATUS 8.1. An apparatus with a standard illuminant suitable for measuring color in the CIELAB system. 9. CALIBRATION 9.1. Calibrate the instrument according to the manufacturer’s instructions prior to making color measurements. The instrument should be suitable for measuring the color of the field, and the measuring head should be sized accordingly. 10. PROCEDURE 10.1. If measuring color for the first time on a particular specimen, select ten dome locations and ten field locations for color measurement. The locations should be selected to be representative of the typical condition of the specimen; no locations with unusual markings (ink markings, scuff marks, or excess concrete on the surface) should be selected. The locations should be selected randomly and be well distributed over the surface of the specimen. Note the locations for future comparative measurement. Note 1: An instrument with a small measuring head that can fit between the domes has been found to produce more repeatable measurements on the field. If the instrument cannot make good contact with the surface being measured, ambient lighting conditions have a significant effect on the values obtained. 10.2. If measuring color on a specimen previously measured, measure the color on the same ten domes and ten field locations. Use the same instrument as used previously. Measure the color as outlined in Draft T4-33. 10.3. Select a standard illuminant, observer, and aperture. If this is not the original measurement on the specimen, use the same instrumental conditions as before. Note 2: A D65 standard illuminant and a 2-degree standard observer have been found to be suitable, although other illuminants and observers may be suitable. An 8 mm (0.31 in.) aperture has been found to be suitable. Other apertures, no larger than the top diameter of the dome, may also be suitable. 10.4. Measure the color using the instrument, and record the data. Note 3: Because the surface roughness of many detectable warning systems is high, variations in the color measured in the ten locations is expected. For this reason, an average is calculated and used in the calculation of color difference.

68 T4 - 33 DRAFT 11. CALCULATION OF RESULTS 11.1. C alculate the average L*, a*, and b* value s of the domes and field separately by averaging the ten measurements. This is the average color reading for the specimen. Domes and field are calculated and reported separately. 11.2. Calculate color difference between current reading and previous reading using the following equations. Always use the average of the ten measurements as the reading. Color difference is calculated based on the difference between the average s of one set of ten readings and another set previously measured on the same specimen, rather than as the difference between one set of readings and a standard . 11.2.1. reading. 11.2.2. previous reading . 11.2.3. previous reading. 11.2.4. Total color difference: ΔE = (ΔL*)2 + (Δa*)2 + (Δb*)2 Note 4 : Total color difference, ΔE, is generally considered suitable for measuring color difference, although other color difference values, ΔL*, Δa*, or Δb*, may be useful for determining color fade of detectable warning systems and compliance with applicable reg ulations. 12. REPORT 12.1. The report shall include the following: 12.1.1. The sample identification assigned according to the Draft T4 - 33 . 12.1.2. Type, manufacturer, and , if known , lot number of the detectable warning system(s) tested. 12.1.3. Measured L*, a*, and b* values . 12.1.4. Averaged L*, a*, and b* values . 12.1.5. Calculated color difference between current value and levels at previous exposures. 12.1.6. List of previous exposure regimes and test durations to which the sample has been exposed. 12.1.7. Make and model of instrument used. 12.1.8. Illuminant , observer and aperture used. 13. PRECISION 13.1. Data not available at this time. Change in lightness: ΔL* = L*2 − L*1, where L*2 is the current reading, and L*1 is the previous Change in redness/greenness: Δa* = a*2 − a*1, where a*2 is the current reading, and a*1 is the Change in yellowness/blueness: Δb* = b*2 − b*1, where b*2 is the current reading, and b*1 is the

69 T4-33 DRAFT 14. REFERENCES 14.1. A useful discussion of the CIELAB color space and color difference calculations is provided in ASTM D 2244 Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.

70 T4-33 DRAFT APPENDIX (Non-mandatory Information) Figure 1-- Measuring the color of the field with a colorimeter with a measuring head of appropriate size to fit between the domes.

71 T4-33 DRAFT Figure 2-- Measuring the color of a dome.

72 T4-33 DRAFT Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning Systems Designation: Draft T4-33, Part 7 1. SCOPE 1.1. This test method covers the measurement of dome shape and geometry of detectable warning systems. The Americans with Disabilities Act Accessibility Guidelines (ADAAG) provides geometric recommendations for the domes and dome spacing of detectable warning systems. This evaluation is intended to provide a basis for quantifying potential changes in dome shape and geometry as the result of laboratory exposure tests. 1.2. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 3. TERMINOLOGY 3.1. Dome: The truncated dome on the detectable warning system. 3.2. Field: The space between the domes on the detectable warning system. The field is level with the surrounding concrete. 4. SUMMARY OF TEST METHOD 4.1. This method is used to measure the geometry of the domes on a detectable warning system, and to compare the measured values to a specification or to another sample. 5. SIGNIFICANCE AND USE 5.1. This method is intended to be used as part of Draft T4-33, to evaluate the durability of detectable warning systems. 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

73 T4-33 DRAFT 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4-33, are required. 8. APPARATUS 8.1. Calipers, either dial or digital, 250 mm (6 in.) span. 8.2. Depth Gauge. The depth gauge consists of a gauge plate and a dial gauge. The gauge plate shall be a flat square plate, measuring a minimum of 75 mm by 75 mm (3 in. by 3 in.), with a hole in the center for a dial gauge. The dial gauge shall have a minimum travel of 12 mm (0.5 in.), measure to a precision of 0.25 mm (0.01 in.), and have a tapered measuring point that does not penetrate the detectable warning system surface. 9. CALIBRATION 9.1. Zero calipers in a closed position. 9.2. Zero the displacement gauge against a flat surface. 10. PROCEDURE 10.1. Use the calipers to measure the dome bottom diameter, dome top diameter, and the base-to-base spacing of nearest domes. Figure 1 provides a schematic of the measurements to be made, and the current ADAAG recommendation. Measure these values on four different domes. Mark the domes measured on a data sheet. Note 1: For the purposes of this evaluation test, the diameter of the top and bottom of some domes is not clearly delineated from the sides. In these cases, the measurement should be taken from the location that most closely appears to be the point of greatest change in the curvature of the dome. 10.2. The displacement gauge is used to measure dome heights. Place the gauge plate over four domes and measure the distance between the gauge plate and the main surface of the field (see note 2). Measure the depth of four different areas. Mark the locations measured on a data sheet. Note 2: For the purposes of this evaluation test, the measured height of the dome includes any texture or any features that may provide slip-resistance on the top surface of the dome. For specimens with features on the field, such as discrete conical features regularly arranged on the field, the tapered measuring point of the dial gauge will measure the flat area of the field. Therefore, the measurement may include surface features on the dome tops, but not on the field.

74 T4-33 DRAFT Figure 1—ADAAG dome dimensions, from Figure 705.1, Americans with Disabilities Act and Architectural Barriers Act Accessibility Guidelines, July 23, 2004, United States Access Board. 11. CALCULATION OF RESULTS 11.1. Calculate the center-to-center spacing by adding one dome base diameter to the base-to-base spacing of nearest domes. 12. REPORT 12.1. The report shall include the following: 12.1.1. The dome bottom diameter, dome top diameter, base-to-base spacing, calculated center-to-center spacing and dome height for each location measured. 12.1.2. For exposed specimens, calculate the change in dimensions from those obtained on the unexposed specimen. 13. PRECISION 13.1. Data not available at this time. 14. REFERENCES 14.1. Americans with Disabilities Act and Architectural Barriers Act Accessibility Guidelines, July 23, 2004, United States Access Board.

75 T4-33 DRAFT Recommended Method of Test for Coating and Single Dome Bond in Detectable Warning Systems Designation: Draft T4-33, Part 8 1. SCOPE 1.1. This test method covers testing of the bond of coatings on detectable warning systems and the bond of single surface-applied domes to the concrete substrate. Bond of the coating to the field and to the dome is tested. Some detectable warning systems are coated to provide slip resistance or color contrast with the surrounding sidewalk. If the coating becomes debonded from the substrate, the detectable warning system may no longer be slip resistant and the system may not meet color contrast requirements for the system. Other detectable warning systems consist of an array of surface-applied single truncated domes adhesively bonded to the concrete substrate. If the domes become debonded, functionality of the detectable warning system could be reduced. The coating bond and adhesive strength of surface-applied domes will be measured according to ASTM D 4541 Standard Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers. 1.2. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM D 4541 Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers 3. TERMINOLOGY 3.1. Dome: The truncated dome on the detectable warning system. 3.2. Field: The space between the domes on the detectable warning system. The field is level with the surrounding concrete. 3.3. Surface-applied single dome: A single truncated dome that is adhered to a concrete substrate as part of an array of separately applied domes composing a detectable warning system. 4. SUMMARY OF TEST METHOD 4.1. This method tests the adhesion of coatings and single surface-applied domes to detectable warning systems. Three adhesion tests will be conducted for each tested condition. Coating bond tests will be conducted at room temperature and elevated temperature (60°C).

76 T4-33 DRAFT 5. SIGNIFICANCE AND USE 5.1. Coating adhesion can be an indicator of coating durability. Coating performance may be important to maintaining color contrast of detectable warning systems, if the substrate is of a different color, and to maintaining slip resistance of detectable warning systems, if the coating is textured to provide slip resistance. Coating may become degraded through exposure. Ultraviolet exposure can degrade polymeric coatings, leading to fading, cracking, and chipping. Abrasion from foot traffic or vehicular traffic (including hand carts) can wear away the coating. Cracking of the substrate from freezing and thawing can lead to debonding of the coating at the crack location. For these reasons, it is important to evaluate the bond of the coating to the substrate. 5.2. Dome adhesion is necessary to maintain the integrity of single surface-applied dome-based detectable warning systems. Dome adhesion is adhesive dependent and may be affected by exposures producing stress-generating thermal gradients and adhesive degradation. For these reasons, it is important to evaluate the adhesion of the domes to the substrate. 5.3. This method is intended to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems. 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4-33 are required. Only specimens with coatings or with single surface-applied domes are required for this test. 8. APPARATUS 8.1. An adhesion tester, consistent with Type V described in ASTM D 4541-02. The diameter of the dolly should be no greater than the top dome diameter. Note 1: A 20 mm diameter dolly has been found to be suitable for the test, although a smaller dolly may be considered. 9. CALIBRATION 9.1. Calibrate the equipment according to the manufacturer’s recommendations. 10. PROCEDURE 10.1. Follow the procedures outlined in Section 7 of ASTM D 4541-02, with the additional requirements outlined as follows: 10.2. For coated samples: 10.2.1. Test the adhesion of the coating over three domes and three areas of field at 21–27°C (70–80°F).

77 T4-33 DRAFT 10.2.2. Test the adhesion of the coating over three domes and three areas of field at a surface temperature of 60 ± 3°C (140 ± 5°F). Note 2: The sample may be heated by placing it in an oven, by using heat lamps to heat the surface, by using a heating blanket to heat the surface, or other methods. The adhesion should be tested promptly after removal of the heat source so that the surface remains within the temperature range described in Section 10.2.2. Note 3: The dollies should be adhered to the surface with an adhesive suitable for high temperature testing prior to heating the specimen. Note 4: More than three areas may need to be tested for each temperature condition to ensure that three results indicating cohesive or adhesive failure of the coating, the coating/detectable warning system or the dome/substrate interface (and not failure of the adhesive used to fix the dolly) are obtained. 10.3. For single surface-applied domes: 10.3.1. The test will be performed as a test of adhesion of the single surface-applied domes to the substrate, rather than a test of the coating itself. This test is performed in addition to the tests of the coating described in Section 10.2. 10.3.2. As necessary, remove the coating from the surface of the single surface-applied dome to be tested. This is necessary if initial tests indicate that the coating fails prior to the single surface- applied dome. If the single surface-applied dome fails before the coating, coating removal is not necessary. Coating can be removed by abrading with abrasive paper or suitable solvent. The means of coating removal should not affect the bond of the single surface-applied dome to the substrate. 10.3.3. Test the adhesion of three single surface-applied domes at room temperature. 10.3.4. Test the adhesion of three single surface-applied domes at a surface temperature of 60 ± 3°C (140 ± 5°F). Note 5: More than three areas may need to be prepared and tested for each temperature condition to ensure that three results indicating cohesive or adhesive failure of the coating, the coating/detectable warning system or the dome/substrate interface are obtained. Note 6: The dollies should be adhered to the surface with an adhesive suitable for high temperature testing prior to heating the specimen. Royal Double Bubble Extra Fast Setting Epoxy has been found to be suitable for the room temperature testing. Loctite 9340 Hysol was identified as suitable for elevated temperature testing, although other products may also be suitable. 11. CALCULATION OF RESULTS 11.1. Calculate the results according to Section 8 of ASTM D 4541-02. 12. REPORT 12.1. Report the results according to Section 9 of ASTM D 4541-02.

78 T4-33 DRAFT 13. PRECISION 13.1. Data relating to the precision of this method relating to detectable warning systems is not available at this time; however, precision and bias information is available in Section 10 of ASTM D 4541-02.

79 T4-33 DRAFT Recommended Method of Test for Slip Resistance of Detectable Warning Systems Designation: Draft T4-33, Part 9 1. SCOPE 1.1. This test method covers the measurement of slip resistance of detectable warning systems. In use, detectable warning systems are placed as outdoor walking surfaces, often on inclined planes. Consequently, the surface must be resistant to slip. This method is applicable for use in evaluating the slip resistance of detectable warning systems as part of a laboratory testing program. 1.2. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.3. ASTM F 609-05, Standard Test Method for Using a Horizontal Pull Slipmeter (HPS) 3. TERMINOLOGY 3.1. Dome: The truncated dome on the detectable warning system. 3.2. Field: The space between the domes on the detectable warning system. The field is level with the surrounding concrete. 4. SUMMARY OF TEST METHOD 4.1. This method evaluates the slip resistance of detectable warning systems that have and have not been exposed to the exposure test methods referenced in Draft T4-33. Slip resistance is determined by the horizontal force required to move the slipmeter from a position of rest on the detectable warning system. 5. SIGNIFICANCE AND USE 5.1. This evaluation method is intended to measure the slip resistance of detectable warning systems that are cast into concrete. 5.2. This test method is to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems.

80 T4 - 33 DRAFT 6. SAFETY HAZARDS 6.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7. TEST SPECIMENS 7.1. Test specimens prepared in accordance with Draft T4 - 33 are required. 8. APPARATUS 8.1. The slipmeter consists of a steel plate , feet , a p ull chain, and a force gauge. 8.1.1. Slipmeter plate : A schematic of the slipmeter plate is shown in Figure 1. The dimensions of the plate are required to keep the center of the mass at the same location for varying dome spacing. The mass of the slip meter is approximately 2.5 kg (5.5 lb) . 8.1.2. Feet : Three feet are used on the slipmeter. Provide a Neolite wearing surface as described in Section 7 of ASTM F 609 - 05. The wearing surface is glued to a metal support that fits in the slots in the slipmeter plate. Slipmet er feet shall be able to be fixed at any point in each slot in the slipmeter plate. 8.1.3. Pull chain : A rigid chain, for example, fabricated of metal links, is used to pull the slipmeter with the force gauge. 8.1.4. Force gauge . A digital or analog force gauge with t he following specification s shall be used to measure the pull force on the slipmeter plate: – Minimum capacity: 50 N (11 lbf) – Precision: 0.1 N (0.02 lbf) – Peak hold function 9. CALIBRATION 9.1. Condition test feet and test specimen for at least 24 hours in atmosphere maintained at 21 ± 6 ° C ( 70 ± 10 °F) . 9.2. Zero the force gauge with the pull chain attached. Calibrate the slipmeter weight by hanging the slipmeter plate and feet vertically from the force gauge. Record this measurement as the s lipmeter weight.

81 T4 - 33 DRAFT 10. PROCEDURE 10.1. One slipmeter measurement is defined as the average of four slipmeter readings, taken at 0, 90, 180, and 270 degree orientations. 10.2. Before each measurement, p repare the feet as directed in Sections 10.1 through Sections 10.4 of ASTM F 609 - 05 . 10.3. Connect the force gauge to the slipmeter base by the pull chain. 10.4. Prepare the slipmeter for taking readings on the domes and on the field according to the procedure given below. Do not use additional force to press the slipmeter on to the s urface. Use only the slipmeter self - weight to hold the slipmeter in place. 10.4.1. To perform one reading on the domes , align the feet in the channels of the slipmeter to center each on the top of a dome. Place the slipmeter on top of the dome surface. 10.4.2. To perfo rm one reading on the field, keep the feet aligned in the same orientation as used for the dome reading. Place the feet of the slipmeter in the spaces between the domes. Leave space between the feet and the domes in the direction of the desired pull direct ion. 10.5. Pull the force gauge horizontally, aligned with the longitudinal axis of the slipmeter base. Increase the pull force gradually until the slipmeter moves. 10.6. Record the maximum pull force reached on the force gauge. 10.7. Repeat steps 10.4 to 10.6 three times for each measurement, rotating the slipmeter 90 degrees each time. 10.8. Take four sets of measurements of the slip r esistance: two locations on the domes and two locations on the field of the specimen . 11. CALCULATION OF RESUL COF = (horizontal pull force)/(slipmeter weight) TS 11.1. Determine the coefficient of friction (COF) for each reading using Equation 1. Equation 1 11.2. Average the four coefficient of friction readings for each set of measurement s . Note 1: The coefficient of friction is typically between 0 and 1, but in some cases may exceed 1.

82 T4 - 33 DRAFT 12. REPORT 12.1. Report each measurement obtained for the domes and the field. 12.2. Report the average of the measurements for the domes and the average of the measurements for the field. 12.3. F or unexposed specimens, compare these numbers to values provided in any governing specification , if values are available in the specification . 12.4. For exposed specimens, compare these numbers to those obtained on the unexposed specimen. 13. PRECISION 13.1. Data not available at this time.

83 T4 - 33 DRAFT Figure 1. Schematic view of slipmeter plate, with required angles and slot dimensions.

84 T4-33 DRAFT Recommended Method of Test for Resistance to Impact from Simulated Snowplow Blade of Detectable Warning Systems Designation: Draft T4-33, Part 10 1. SCOPE 1.1. This test method covers the evaluation of detectable warning/concrete systems at freezing temperatures subjected to impact from a simulated snowplow blade. 1.2. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 2.2. ASTM Standards 2.2.1. ASTM E 18 Standard Test Methods for Rockwell Hardness of Metallic Materials 3. SUMMARY OF TEST METHOD 3.1. This method evaluates the durability of individual domes in detectable warning systems when they are subjected to impact from a simulated snowplow blade. The blade is mounted in a swinging pendulum and strikes a single dome from the side at a controlled energy. 4. SIGNIFICANCE AND USE 4.1. This test method is intended to evaluate performance of detectable warning systems that are cast into concrete when struck by a simulated snowplow blade. This performance is expected to be indicative of performance of detectable warning systems when subjected to snow removal operations. 4.2. This method is intended to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems. 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

85 T4-33 DRAFT 6. TEST SPECIMENS 6.1. A single test specimen consisting of a detectable warning system embedded or fixed to a concrete slab prepared in accordance with Draft T4-33 is required. 7. APPARATUS 7.1. Cold chamber capable of bringing the surface temperature of the detectable warning systems to -4 ± 3°C [24.8 ± 5°F] 7.2. Snowplow Simulation Device—This device is intended to produce an impact on the side of a dome with controlled energy at a controlled height. This device consists of a pendulum system, as pictured in Figure 1. Note 1: Photographs of a system consistent with these requirements are given in the appendix of this method. 7.2.1. Pendulum—The pendulum consists of two connected rigid arms: (1) a rotating arm and (2) a rotating-translating arm. The rotating arm is mounted using a rotary bearing to an axle defining the axis of rotation. The rotating-translating arm is attached to the rotating arm by a connection containing a linear bearing that allows the rotating-translating arm to move along the axis of the pendulum arms. A strike plate holder capable of securely supporting the plate described in Section 7.2.2 is attached to the end of the rotating-translating arm. The portion of the rotating- translating arm extending through the bearing is fitted with a locking collar that serves as a mechanical stop, limiting the extension of the pendulum. The pendulum is defined as follows: 7.2.1.1. The overall length of the pendulum in test configuration is 145 ± 5 cm [57 ± 2 in.]. 7.2.1.2. Total weight of the pendulum (both arms) is 17 ± 0.5 kg [37.4 ± 1.1 lbs.]. Weight of the rotating- translating arm is 13 ± 0.5 kg [28.6 ± 1.1 lbs.] The actual weight of the arms shall be determined to the nearest 0.05 kg [0.1 lbs.]. 7.2.1.3. The distance from the center of mass of the pendulum in the fully extended position to the axis of rotation shall be 70 ± 5 cm [27.6 ± 2 in.]. The actual location of the center of mass shall be determined to the nearest 0.5 cm [0.2 in.]. This location shall be clearly marked on the pendulum. 7.2.1.4. The linear bearing and shaft of the rotating-translating arm shall be designed to produce negligible friction resisting shortening of the pendulum. 7.2.2. Strike Plate 7.2.2.1. Material—The strike plate shall be manufactured from AISI 1065 Steel with a fully pearlitic microstructure and have a hardness of 30–36 HRC, when measured according to ASTM E 18. Note 2: This steel is used in a commercially available snowplow blade. 7.2.2.2. Geometry—The strike plate shall be nominally 5 by 3.8 cm [2.0 by 1.5 in.] and have a thickness of 0.95 ± 0.05 cm [0.375 ± 0.02 in.]. The strike edge shall be machined or ground to produce a 90º angle. Strike plates can be reused provided that the edge is reconditioned between testing.

86 T4 - 33 DRAFT 7.2.3. Release mechanism — A mechanis m for releasing the pendulum from its initial position in a way that does not produce an initial impulse, retardation or l ateral force acting on the pendulum shall be used. This mechanism shall be capable of holding the pendulum at sufficient height to pro duce the energy specified in Section 8.4 .6 . Note 3 : A stable stand supporting a switched magnet has been found adequate. 7.3. Metal s hims of sufficient thickness and number to create a stack of 1 to 3 mm [ 0.04 to 0.12 in.] , to within 0.25 mm [ 0.01 in. ] . 7.4. Surface t emperature measuring device capable of verifying that the detectable warning surface at the time of testing is within the range - 4 ± 3°C [ 24.8 ± 5°F ] . Note 4 : A non - contact infrared thermometer has been found adequate for this task. 7.5. A scale marked out at distance intervals no greater than 0.25 cm [ 0. 1 in. ] in size and a video camera capable of recording at video at 30 Hz or greater. This is for use in the determination of friction losses. 8. PROCEDURE 8.1. Examination of Apparatus — Conduct the followi ng test of the equipment performance before testing each time that the equipment is set up or if there is reason to believe that equipment performance has changed. 8.1.1. Determination of Friction Losses 8.1.1.1. Set up the grid scale and the video camera on opposite side s of the pendulum so that the distance intervals are clearly visible in the video picture behind the end of the pendulum and strike plate. The camera should be positioned at least 3 m [ 10 ft ] from the pendulum along a line perpendicular to the pendulum swing path and at the same height as the pendulum at the beginning of the swing . The field of view should be as tight as possible while still including the end of the pendulum in its return position after complet ing two cycles when released from the starting position defined as follows . 8.1.1.2. With no specimen present, fix the pendulum in the release mechanism at the height necessary to produce 25 ± 2 J [18.4 ± 1.5 lbs- ft] as specified in Section 8.4.6 . 8.1.1.3. Be sure that the position of the end of the strike plate can be clearly seen in the video and b egin recording video . 8.1.1.4. Release th e pendulum and record at least two compete cycles. Repeat two additional times. 8.1.1.5. From the video, obtain pictures of the end of the pendulum before release and at the peak height achieved at the end of each cycle. Identify a single point on the pendulum, such as the corner of the strike plate, and determine the reduction in height during each cycle to the nearest 0.25 cm [ 0.1 in. ] . 8.1.1.6. Calculate the perc ent reduction in energy through each cycle as the ratio of the reduction in height to the initial height at the start of each cycle.

87 T4-33 DRAFT 8.1.1.7. For the test apparatus to be acceptable, the reduction in energy during the first and second cycle shall be no greater than 3%. Note 5: If more than 3% reduction is measured, the device configuration, such as the bearing system or the shape of the translating arms, must be modified. 8.2. Preparation of Samples 8.2.1. Confirm that sufficient clearance is provided surrounding the detectable warning system so that the strike plate will not impact the concrete before striking the test domes. If sufficient clearance is not provided, remove surrounding concrete by grinding or similar operation, taking care not to damage the detectable warning system. Note 6: Attempting to grind the samples after they have been conditioned at freezing temperatures may locally warm the specimen to temperatures greater than the allowable range and is not recommended. 8.2.2. Condition samples to -7ºC [20ºF] in freezing chamber for at least 8 hours. 8.2.3. Hold the specimen surface temperature within the temperature range of -7ºC to -1ºC [20ºF to 30ºF] during transport of the samples from the conditioning chamber to the test apparatus and until the test is performed. Note 7: The use of insulating blankets and ice packs containing salt solution may be useful to achieve this objective. A sodium chloride solution ice bath with 5-8% sodium chloride has been found suitable. 8.3. Preparation of Apparatus 8.3.1. Perform routine inspection of apparatus at start of each test run (consisting of tests performed on three domes of a single type of detectable warning). 8.3.1.1. Visually inspect the strike plate, pendulum, and bearings for damage and wear. 8.3.1.2. If any sign of wear is noted, install a new strike blade in the test head. The strike plate can be used on multiple samples only if very pliable samples are tested. 8.4. Test Procedure 8.4.1. Choose three domes adjacent to the edge of the detectable warning system for testing. Document the locations of testing. Visually inspect each of the domes for signs of damage. If damage is identified, select a different dome. 8.4.2. Position the test specimen such that when the pendulum is hanging freely, the leading edge of the strike plate is aligned over the near edge (i.e., where the dome meets the field) of the dome. Note 8: It is advisable to align the specimens such that the row of domes to be tested is parallel with the axle supporting the pendulum. In this way, the pendulum can be translated along the axle for successive testing. 8.4.3. Fix the test specimen such that it does not move during testing.

88 T4-33 DRAFT 8.4.4. Adjust the pendulum so that the strike plate is centered on the dome. 8.4.5. Set the collar on the rotating-translating arm of the pendulum such that the height of the strike on the domes is 3.0 ± 0.25 mm [0.12 ± 0.01 in.] above the field of the detectable warning system as follows: 8.4.5.1. Measure the height of the dome by determining the distance between the topmost feature on the dome and the field according to the method outlined in Draft T4-33, Part 7 Recommended Method of Test for Dome Shape and Geometry Measurement of Detectable Warning Systems. Subtract 3.0 mm [0.12 in.] from this value to get the offset distance of the locking collar on the rotating- translating arm. 8.4.5.2. Position the pendulum such that the strike plate is resting on the top of the dome to be tested. Release the locking collar. Select a shim or shim stack of thickness equal to the offset distance with a tolerance of 0.25 mm [0.01 in.]. Slide the shim or shim stack between the locking collar and the bearing surface. Snug the locking collar against the shims and securely tighten the collar. Remove the shim or shim stack. 8.4.6. Adjust the location of the release mechanism so that the center of mass of the pendulum before release is elevated sufficiently to produce 25 ± 2 J [18.4 ± 1.5 lbs-ft] of potential energy. Note 9: In SI units, potential energy (U) is calculated as U = mgh, where m = mass in kg, g = 9.81 m/s2 and h = height above resting position of center of mass in meters. In Imperial units, potential energy (U) is calculated as U = wh, where w = weight in pounds and h = height above resting position of center of mass in feet. Note 10: The distance that the end of the pendulum needs to be lifted can be determined based on similar triangles: hend = lpendulum/lcm × hcm, where hend = height above resting position of end of the pendulum, lpendulum = distance from axis of rotation to end of the pendulum, lcm = distance from axis of rotation to center of mass, and hcm = height above resting position of center of mass. 8.4.7. Measure the surface temperature and proceed only if it is within the range -4 ± 3°C [24.8 ± 5°F]. Use an ice pack or other device to cool the specimen if this range is exceeded. Record the temperature at the start of testing of each dome. 8.4.8. Strike the dome with the pendulum five times, performing each strike as follows: Release the pendulum allowing the blade to strike the dome and carry on past the dome. Catch the pendulum before it swings back against the dome. Lift the rotating-translating arm over the dome and attach to the release mechanism. During these strikes, photograph the dome after one, three and five strikes. 8.4.9. Evaluate the condition of the test dome after five strikes. Assign a damage classification based on which of the descriptions given in Table 1 that the observed damage most closely resembles. Note and photograph any unusual characteristics of the dome response. 8.4.10. Repeat the operations outlined Sections 8.4.2 through 8.4.9 for the two remaining domes selected for testing. 9. REPORT 9.1. Report the sample identification assigned according to the Draft T4-33.

89 T4-33 DRAFT 9.2. Report the exposure history of the samples at the time of testing. 9.3. Report type, manufacturer, and, if known, lot number of the detectable warning system(s) tested. 9.4. For each tested dome, report the assigned damage classification. 9.5. Report any deviation from the procedures outlined in this method. 10. PRECISION 10.1. Data not available at this time.

90 T4-33 DRAFT Figure 1. Schematic of Snowplow Apparatus

91 T4-33 DRAFT ANNEX (Mandatory Information) Table 1. Evaluation Criteria Classification Description Examples A No damage B Damage to surface texture or coating only C Dent or indentation produced in main body of dome D Top of main body of dome partially removed E Top of main body of dome fully removed F Nearly all of dome removed from system

92 T4-33 DRAFT APPENDIX (Non-mandatory Information) Release mechanism Strike plate Rotating- translating arm Strike plate Rotating arm Connection Axle

93 T4-33 DRAFT Recommended Method of Test for Resistance to Impact from Falling Tup of Detectable Warning Systems Designation: Draft T4-33, Part 11 1. SCOPE 1.1. This test method covers the evaluation of impact resistance of detectable warning systems. In use, detectable warning systems are subject to impact from a wide variety of sources. Pedestrians carrying objects may drop them, and if a heavy object lands with a concentrated force on a dome, damage can result. Another potential source of impact damage is from wheeled carts and hand trucks being pushed over the surface of detectable warning system. 1.2. This test involves impacts of pre-determined energies on the domes of detectable warning systems cast into concrete. Impact is provided by a weighted falling tup. 1.3. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 3. SUMMARY OF TEST METHOD 3.1. This test method is designed to test the impact resistance and durability of various detectible warning systems. 4. SIGNIFICANCE AND USE 4.1. This test method is intended to evaluate impact resistance of detectable warning systems that are cast into concrete. 4.2. This test method is intended to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems. 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 6. TEST SPECIMENS 6.1. Test specimens prepared in accordance with Draft T4-33 are required.

94 T4-33 DRAFT 6.2. Prior to testing the detectable warning panel, the surface should be clean and dry. Three domes per load will be tested at both room temperature and at -4 ± 3°C (24.8 ± 5°F), for a total of three to six domes tested at room temperature and three to six domes tested at 25 ± 5°F. 7. APPARATUS 7.1. A 25.4 mm (1 in.) diameter hemispherical tup made from steel hardened to a minimum hardness of 54 HRC or harder. The tup will be attached to the impactor described below. 7.2. An impactor to which the tup can be attached securely. The impactor must be allowed to vertically impact the tops of the domes with energies of 27 J and, if desired, 54 J (20 and 40 ft- lbs). Photographs of an impactor that has been used in this testing are provided for reference in Figures 1 and 2. Other apparatus suitable to producing an impact of specified energy with the specified tup may also be used. 7.3. For testing in the cold exposure category according to Draft T4-33, a thermal chamber or freezer to bring the surface temperature of the panels to -4 ± 3°C (24.8 ± 5°F), and a means to verify surface temperature, such as surface thermocouple or surface thermometer. Note 2: As necessary, the sample can be removed from the cold chamber and testing can be conducted in a laboratory environment. If this option is pursued, a means to keep the surface within the desired temperature is required. A sodium chloride solution ice bath with 5–8% sodium chloride has been found suitable. 8. CALIBRATION 8.1. Calibrate the scale of the impact tester to ensure that the impactor is dropped from the desired height. The point at which the impactor touches the top of a dome of the sample is defined as height = 0 cm (0 in.). Note 3: Because of height variations from sample to sample, the zero measurement should be verified for each new panel that will be tested. 9. PROCEDURE 9.1. Place the panel on a flat, rigid surface, such as a concrete floor, that will not absorb the energy of impact. 9.2. Choose three domes per impact energy. Note 4: Experience has indicated that the degree of consolidation of concrete under the detectable warning system panels is affected by installation and varies from specimen to specimen and within a single specimen. The uniformity of consolidation should be checked by sounding the panel prior to testing. Well or poorly consolidated areas can be selected for testing, or, if both types of areas are present on a specimen, both conditions can be tested. Differences in impact resistance may be apparent. Note 1: For example, a 10 kg (22 lb) impactor could be dropped from 27 and 54 cm (11 and 21 in). Different masses could be used from different heights to obtain the same impact energies.

95 T4-33 DRAFT 9.3. Document the locations of the testing. Conduct a visual inspection of each of the domes and note any irregularities in appearance or condition. 9.4. Align the impactor so that the center of the tup will strike the center of the dome. 9.5. Perform impact tests at 27 J and, if desired, 54 J (20 and 40 ft-lbs) at room temperature. Each impact is to be carried out on a separate dome. Three domes are to be impacted per energy. 9.6. If testing for the cold exposure category according to Draft T4-33, perform a second round of impact tests at 27 J and, if desired, 54 J (20 and 40 ft-lbs) at a surface temperature of -4 ± 3°C (24.8 ± 5°F). Each impact is to be carried out on a separate dome not previously impacted. Three domes are to be impacted per energy. 9.7. Evaluate the results according to the criteria provided in Table 1. 10. REPORT 10.1. The report shall include the following: 10.1.1. The sample identification assigned according to the Draft T4-33. 10.1.2. Type, manufacturer, and, if known, lot number of the detectable warning system(s) tested. 10.1.3. Rating for each dome according to the criteria listed in Table 1. 10.1.4. Impact energy for each dome. 10.1.5. Surface temperature. 10.1.6. Any additional comments describing irregularities in the tested domes or system and any deviations from the test procedure outlined herein. 11. PRECISION 11.1. Data not available at this time.

96 T4-33 DRAFT ANNEX (Mandatory Information) Table 1--Evaluation Criteria Classification Description Examples A No Damage B Damage to surface texture or coating only C Damage to less than 25% of the dome D Damage to 25 - 50% of the dome E Damage to 50 - 75% of the dome F Damage to 75 - 100% of the dome

97 T4-33 DRAFT APPENDIX (Non-mandatory Information) Figure 1-- An impact tester used in the performance of these tests. guide tube support

98 T4-33 DRAFT Figure 2--The impact head, showing the weight and hemispherical tup. hemispherical tup weight

99 T4-33 DRAFT Recommended Method of Test for Wear Resistance of Detectable Warning Systems Designation: Draft T4-33, Part 12 1. SCOPE 1.1. This test method covers the evaluation of wear resistance of detectable warning systems. Note that this wear resistance test is distinguished from the procedure outlined in Draft T4-33, Part 4 Recommended Method of Test for Abrasion Exposure of Detectable Warning Systems. That test is intended to evaluate the resistance of the test sample to an intense abrading action, while this test is intended to condition the sample in preparation for other evaluation tests. 1.2. This evaluation test is intended to be conducted as part of the test protocol outlined in Draft T4- 33, which outlines the exposure and evaluation methods for determination of durability of detectable warning systems. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards 2.1.1. Draft T4-33 Recommended Method of Test for Durability of Detectable Warning Systems 3. SUMMARY OF TEST METHOD 3.1. This method evaluates the durability of domes in detectable warning systems when they are subjected to wearing action produced by abrasive paper. For this test, the test sample consists of a representative portion of the detectable warning system removed from the larger test specimen. This sample is held with known force against a translating surface on which abrasive paper has been fixed. 4. SIGNIFICANCE AND USE 4.1. This test method is intended to evaluate the response of detectable warning systems to an abrasive action. This response of the test samples to this action is expected to be indicative of performance of detectable warning systems when subjected to abrasion from foot traffic. 4.2. This method is intended to be used as part of Draft T4-33 to evaluate the durability of detectable warning systems. 5. SAFETY HAZARDS 5.1. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

100 T4-33 DRAFT 6. TEST SPECIMENS 6.1. The test specimens are two 15.2 cm (6 in.) diameter circular representative portions cut from the detectable warning system. 6.1.1. The location of samples should be selected to maximize the included number of domes, while maintaining symmetry. Any partial domes at the edges of the sample should be removed by grinding or other means. A dome shall be considered partial if less than 95% of the area based on the bottom diameter is within the circular portion. 6.1.2. When the sample is to be tested in an unexposed condition, it may be obtained from a representative sample of the detectable warning system that has never been installed in concrete. 6.1.3. When the sample is to be tested in an exposed condition, such as may be done to evaluate the influence of exposure regimes on wear resistance, the specimens are cut or cored from test specimens prepared and exposed in accordance with Draft T4-33. Note 1: If the samples are cored and it is possible to remove the detectable warning system from the backing concrete in the core without damaging the sample, it is advisable to do so. Otherwise, it is advisable to cut the backing concrete such that approximately 1 cm (½ in.) of concrete remains attached to the sample. 6.1.4. The sample must be rigidly supportable in a horizontal plane. Detectable warning systems that are flexible should be fixed to a rigid plate, such as a ¼ in. or thicker steel plate, to assist in achieving this goal. 7. APPARATUS 7.1. Abrader wheel—A 460 mm (18 in.) diameter or greater power-driven abrader wheel, such as a lapping wheel commonly used for preparing the surface of concrete samples, shall be used. Self- adhesive abrasive paper shall be fixed to the wheel. 7.1.1. This wheel shall rotate at 45 ± 1 rpm. 7.1.2. The abrasive disc shall be 60-grit aluminum oxide X-weight abrasive cloth. The disc shall conform with the following specifications: • The backing shall be abrasive grade X-weight cloth. • The abrasive shall be P60 FEPA-graded, coated abrasive grade, low titania, heat treated aluminum oxide. Note 2: Aluminum oxide, resin bond, X weight heavy duty cloth discs with 60 grit adhesive available from Global Abrasive Products, 62 Mill Street, Lockport, New York 14094 conforms with these requirements. 7.2. Sample frame—The two test samples will be supported in a mechanism consisting of the sample frame and sample assembly. This mechanism shall maintain the surface of the detectable warning in a horizontal orientation (parallel to the plane of the abrader wheel) and allow fixing the rotation of the assembly relative to the frame at four 90º intervals, while allowing the sample assembly to

101 T4-33 DRAFT freely translate vertically . The sample frame is fixed over the abrader wheel so that the samples are positioned 11.4 ± 0.25 cm ( 4.5 ± 0.1 in.) from the center of rotation of the wheel. 7.3. Sample assembly — The sample (or the sample fixed to a rigid plate) shall be supported within the sa mple frame o n a sample assembly. This assembly shall be rigid and weigh 4.5 ± 0. 1 kg ( 10 ± 0.2 lbs) . Since the weight of the sample itself may vary, a means for adjusting the weight of the combined sample assembly using steel plates of various thickness es or similar is needed. The assembly shall provide a means for fixing the rotation of the assembly relative to the frame at four 90º intervals. Note 3 : A p hotograph and sketch of a system consistent with these requirements is given in the a ppendix of this me thod. Note 4 : The alignment of the assembly and frame is important to produce an even wearing action on each of the domes in the sample. No chattering should occur. 7.4. Balance for weighing sample assembly shall have capacity greater than 4.5 kg (1 0 lbs) and resolution of 0.01 kg (0.02 lbs). 8. PROCEDURE 8.1. Install a new sheet of abrasive paper on the abrader wheel. 8.2. Install the sample in the assembly. 8.3. Measure the height of two domes on each of the two test sample s by determining the distance between the topmost feature on the dome and the field according to the method outlined in Draft T4-33, Part 7 Recommended Method of Test for Dome Shape and Geometry Measurement of De- tectable Warning Systems. Note the location of the measured domes. 8.4. Install the assembly in the frame . A djust the orientation of the sample relative to fixed rotation intervals in the frame mechanism so that, at the start of the test , the overlap in paths formed in the abrasive paper by each dome is minimized. In other words, the number of independent paths produce d through the abrasive paper by the domes should be maximized . 8.5. Fix the test specimen such that it does not rotate . 8.6. Start the rotation of the sample wheel and abrade the samples for 60 seconds. Rotate the specimen 90º cloc kwise . 8.7. R epeat the previous step three times for a total of 4 minutes of abrasion . 8.8. Repeat the me asure ment of the height of each dome tested in Section 8 .3 . 9. REPORT 9.1. Report the sample identification assigned according to the Draft T4 - 33. 9.2. Report the exposure history of the samples at the time of testing. 9.3. Report type, manufacturer, and , if known, lot number of the detectable warning system(s) tested.

102 T4-33 DRAFT 9.4. For each tested dome, report the initial and final dome height and the change in height. 9.5. Report any deviation from the procedures outlined in this method. 10. PRECISION 10.1. Data not available at this time.

103 T4-33 DRAFT APPENDIX (Non-mandatory Information) Figure 1 - Photo of wear resistance sample frame assembly.

104 T4-33 DRAFT Figure 2 - Schematic of cross section of sample assembly used to hold test specimen vertically in sample frame. The size and number weights were adjusted to produce the specified assembly weight.