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APPENDIX C DIAMETRAL TEST PROCEDURE FOR RESILIENT MODULUS OF ASPHALT CONCRETE C - 1

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APPENDIX C PROPOSED PROTOCOL 1. SCOPE I.1 General This proposed protocol describes procedures for the determination of the resilient modulus of hot mix asphalt concrete (HMA), using repeated load indirect tensile test techniques. The procedure involves resilient modulus testing over a range of temperatures and loads. I.2 Testing Prerequisites Resilient modulus testing shall be conducted after system response has been verified by testing synthetic specimens, as outlined in section 8. ~ ofthis protocol. I.3 Sample Size Resilient modulus testing shall be conducted on 4 inch diameter specimens that are 1.5 inches to 4 inches in thickness; for medium (or fine) gradation mixes. For base courses or large-stone surface mixes a 6 inch diameter specimen with thickness between 3 and 4.5 inch is recommended. Desired thickness for a 4 inch diameter specimen is 2.5 inches and for a 6 inch diameter specimen desired thickness is 3.75 inches. I.4 Pretest Tensile Strength Prior to performing the resilient modulus test the indirect tensile strength shall be determined for one test specimen taken from the same layer and as close as possible to the location of the core specimenfs) to be tested for resilient modulus. For lab specimens, a sample having the same mix properties will be selected for indirect tensile strength testing. The indirect tensile strength test is performed as a basis for selecting the loading levels for the resilient modulus testing. Test shall be performed in accordance with attachment A of the SHRP P07 protocol (November I, 19921. I.S Definitions The following definitions are used throughout this protocol: Layer - that part of the pavement produced with similar material and placed with similar equipment and techniques. The layer thickness can be equal to or less than the core thickness or length. (b) Core - an intact cylindrical specimen of pavement materials which is removed from the pavement by drilling and sampling at the designated C-2

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core location. A core may consist of, or include, one, two or more different layers. (d) Test Specimen - that part of the layer which is used for, or in, the specified test. The thickness of the test specimen can be equal to or less than the layer thickness. Haversine Shaped Load Form - the required load pulse form the resilient modulus test. The load pulse is in the form (] - cos O)/2 and the cyclic load is varied from the contact load (Pcon~ac~) to the maximum load (Pma,`~' as shown in Figure C- ~ (from SHRP P07 protocol). (e) Maximum Applied Load (PmaX) - the maximum total load applied to the sample, including the contact and cyclic (resilient) loads. Pmax = Pcontact + Pcyclic (g) (h) Contact Load (PContact) - the vertical load placed on specimen to maintain a positive contact between the loading strip and the specimen. At 41F At 77F, PContact = 0.05 PmaX PContact = 0.04 PmaX At 104F, PContact = 0.04 Pma,,, not less than 5 Ibs, but not more than 20 Ibs. Cyclic Load (Resilient Vertical Load, PCyclic) - load applied to a specimen, respectively, which is directly used to calculate resilient modulus. Pcyclic = Pmax ~ Pcontact Instantaneous Resilient Modulus - determined from the deformation-time plots (both horizontal and vertical) as described herein. To determine the instantaneous deformation values, it is recommended to perform regression in three portions of the deformation curve: I. Linear regression in the straight portion of the unloading path 2. Regression in the curved portion that connects the unloading path and the recovery portion to yield the following hyperbolic equation: Y=a+b/X C-3

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where X = Y = deformation value, time, and a, b = regression constants. Regression in the recovery portion between 40% and 90% (recommended range) of rest period to yield a hyperbolic equation. A tangent should be drawn to this hyperbola at the point corresponding to 55% (recommended point) of the rest period. Two linear equations, one from the unloading path and the other from the tangent of the hyperbola in the recovery period, shall be solved to determine the intersection. Then the point on the hyperbolic curve .. . .. .. ~ . ~ . . .. , ~ . (i, corresponding to the time coordinate ot the intersection tior convenience, say point A) is selected to determine the instantaneous deformation by subtracting the deformation at the point A from the peak deformation. Total Resilient Modulus - determined from the deformation-time plots (both horizontal and vertical) by subtracting deformation obtained at the end of one load-unload rest period cycle, as determined by taking the average of deformation values obtained for the time period between 85% completion to 95% completion of the rest period from the peak deformation values. This value includes both the instantaneous recoverable deformation and the time-dependent continuing recoverable deformation during the rest-period portion of one cycle. 2. APPLICABLE DOCUMENTS SHRP protocol P07 3. SUMMARY OF METHOD Resilient Modulus for Asphalt Concrete 3.! The repeated-Ioad indirect tension resilient modulus test of asphalt concrete is conducted through repetitive applications of compressive loads in a haversine waveform. The compressive load is applied along a diametrical plane of a cylindrical Asphalt Concrete specimen. The resulting horizontal and vertical deformations are measured. Values of resilient Poisson's ratio shall be calculated using recoverable vertical and horizontal deformations. The resilient modulus values are subsequently calculated using the calculated Poisson's ratio. 3.2 Two separate resilient modulus values are obtained. One, termed instantaneous resilient modulus, is calculated using the recoverable horizontal deformation that occurs during the unloading portion of one load-unIoad cycle. The other, termed total resilient modulus, is calculated using the total recoverable deformation which C-4

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includes both the instantaneous recoverable and the time-dependent continuing recoverable deformation during the unload or rest-period portion of one cycle. 3.3 For each resilient modulus test, the following general procedures must be followed: (a) ~ ne tensile strength Is determined on a test specimen at 77 ~ 2F using the procedure described in attachment A to SHRP P07 protocol. The value of tensile strength obtained from this procedure is used to determine the indirect tensile stress and corresponding compressive load to be respectively applied to the test specimens during the resilient modulus determinations. (b) The test specimenfs) are to be tested along one diametral axis at one rest period (i.e., 0.9 seconds) and at testing temperatures of 4 l, 77 and 1 04F plus or minus two degrees F (5, 25, and 40C plus or minus one degree C). For each test temperature, repetitive haversine load pulses of 0.! second duration followed by a rest period of 0.9 seconds between load pulses are applied to the individual test specimens. The magnitude of the load pulse will be selected to produce a predefined indirect tensile stress on the specimen based on a percentage of the indirect tensile strength (see section 3.3(a) above). The temperature testing sequence includes initial testing at 4 ~ OF followed by testing at 77F, and final testing at 1 04F. After completion of resilient modulus testing at 104F, the test specimen shall be returned to 77F and an indirect tensile strength shall be performed in accordance with attachment A of the SHRP P07 protocol. This test is performed to determine the tensile strength of the specific specimen actually used in resilient modulus testing. For these specimens the loading axis shall be 90 to the axis used for modulus determinations. SIGNIFICANCE AND USE Resilient modulus can be used in evaluations of materials quality and as input for pavement design, evaluation and analysis. With this method, the effects of temperature and load on resilient modulus can also be investigated. s. SPINS 5.1 Testing Machine The testing machine shall be a top loading, closed loop, electrohydraulic testing machine with a function generator which is capable of applying a haversine shaped load pulse over a range of load durations, load levels, and rest periods. C-S

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5.2 Loading Device The loading device should be capable of testing 4 inch and 6 inch diameter specimens with thickness up to 4.5 inches. The device should be compact enough to be used within the environmental chamber. It should have a fixed bottom loading plate and a moving upper loading plate. The movement of the upper plate should be guided by two columns, one on each side of the specimen and equidistant from the loading axis and the loading strips, to ensure it has minimal translational or rotational motion during loading of the specimen. The guide columns shall have a frictioniess bearing surface that shall be kept well lubricated. The surfaces of the guide columns shall be frequently inspected for any grooves caused due to friction. Alignment of the device, within the loading system, shall be achieved so that such friction is limited to the minimum possible extent. The upper plate shall be rigid enough to prevent any deflections during loading. If heavyweight plates are used to achieve rigidity, the testing system should be able to counteract all the weight, such that no more than 2 Ibs. of load is transferred to the specimen when load is not being applied. It is recommended that high strength material be used to achieve rigidity and keep the weight small. The loading strips shall preferably be perpendicular to the line connecting the two guide columns, so that visual alignment of the sample in the device is easier. 5.3 Temperature Control Systems The temperature-control system should be capable of maintaining temperature control within 2F (~.~C), at settings ranging from 41F (5C) to 104F (40C). The system shall include a temperature-controlled cabinet large enough to house the loading device, and a cabinet adequate to pre-condition at least three test specimens at a time prior to testing. 5.4 Measurement and Recording System The measuring and recording system shall include sensors for measuring and simultaneously recording horizontal and vertical deformations and loads. The system shall be capable of recording horizontal and vertical deformations in the range of 0.00001 inch (0.00025 mm) of deformation. Load cells shall be accurately calibrated, with a resolution of 2 Ibs. or better. 5.4.! Data Acquisition - The measuring or recording devices must provide real time deformation and load information and should be capable of monitoring readings on tests conducted to ~ Hz. Computer monitoring systems are recommended. The data acquisition system shall be capable of collecting at least 200 scans per second (a scan includes all deformation and load values at a given point of time). Capability to have real-time plots (simultaneous to the data collection by the computer monitoring system) shall also be provided to check the progress of the test. If strip chart recorders are used without computer monitoring systems, the plotting scale shall be adjusted such that there is a balance between the C-6

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scale reduction required as a result of the pen reaction time and the scale amplification needed for purposes of accurate measurement of values from a plot. Actual load values, and not the intended load values, shall be used for calculation purposes and so the data acquisition system shall also be capable of monitoring the load values continuously cluring testing. S.4.2 Deformation Measurement - The vertical deformation shall be measured on the surface of the specimen by mounting a LVDT between gage points along the vertical diameter. The gage length shall be three quarters the diameter of the specimen. if possible, two EVD[s, one each on the front and back faces of the specimen, should be used and the deformation averaged. Extensometers (or a comparable mountable device) should be used for the measurement of the horizontal deformation. The EVDrs shall be frequently calibrated, preferably each day before testing. Extensometers, if used, should also be calibrated from time to time. The surfaces on which the knife edges of the extensometer assembly rests should be kept smooth and free of grooves. 5.4.3 Load Measurement- The repetitive loads shall be measured with an electronic load cell with a capacity adequate for the maximum required loading, and a sensitivity of 0.5% of the intended peak load. At higher temperatures, this limit can be relaxed to a sensitivity of ~ ~ Ibs. During periods of resilient modulus testing, the load cell shall be monitored and checked once a month with a calibrated proving ring to assure that the load cell is operating properly. Additionally, the load cell shall be checked at any time that the QA/QC testing with in-house synthetic specimens (section 8.1 ) indicates a change in the system response or when there is a suspicion of a load cell problem. 5.5 Loading Strips Steel loading strips, with concave sample contact surfaces, machined to the radius of curvature of a 4.000 ~ 0.004 inch diameter specimen or a 6.000 ~ 0.006 inch diameter specimen, are required to apply load to the test specimens. The contact area of the loading strip shall be 1/2 inches wide and 3/4 inches wide for 4 inch and 6 inch diameter specimens respectively. The outer edges of the curved surface shall be filed lightly to remove sharp edges that might cut the specimen during testing. Thin lines should be drawn along the length of the strip at its center, to help in alignment. Also, appropriate markings should be made so as to center the specimens within the length of the strips. This could be either done by matching the center of specimen with a mark at the center of the strip or by positioning the specimen between two marks at the ends of the specimen thickness, or both. 5.6 Marking and Alignment Devices C-7

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A marking device shall be used to mark mutually perpendicular axes on the front and back faces of the specimen through the center. The device shall be capable of marking axes on different sizes (thickness and diameter) of specimens. The axes shall be simultaneously marked on the front and back faces of the specimen to ensure that the axes on the front and back lie in a single plane. An alignment device shall be used to position and place the vertical EVDT along the vertical diameter of the specimen and hold it there, until the glue that holds the EVDT cures. It shall be easily removable, without disturbing the EVDT (once He glue cures), and shall not be destructively mounted on the specimen. The device shall preferably have the capability to mount the EVDT at different gage lengths but mainly at a gage length of three quarters of the diameter of the specimen. The EVDT when positioned shall be parallel to the surface of the specimen and in line with the vertical diameter of the specimen. The EVDT shall be as close to (but not touching) the surface of the specimen so as to minimize the bulging effect. To ensure uniform test results, a height of 0.2 inch is recommended. The axis of EVDT shall not be at a distance greater than 0.25 inch from the surface of the specimen. 6. TEST SPECDIENS 6.1 Core specimens - Cores for test specimen preparation, which may contain one or more testable layers, must have smooth and uniform vertical (curved) surfaces, and must be no less than 3.X5 inch or more than 4.15 inch in diameter. Cores which are obviously deformed or have any visible cracks must be rejected. Irregular top and bottom surfaces shall be trued up as necessary, and individual layer specimens obtained by cutting with a diamond saw using water or air as a coolant. It is recommended that base course or large-stone mixes shall be no less than 5.85 inches or more than 6. ~ 5 inches in diameter. 6.2 The test specimens designated for testing shall not be more than 4 inches in thickness. However, for base course or large-stone mixes the thickness shall not be greater than 4.5 inches. If a core specimen has more than one layer the layers shall be separated at the layer interface by sawing. Layers containing more than one lift of the same material as placed under contract specification, may be tested as a single specimen. Traffic direction shall be marked on each layer after cutting, to maintain the correct orientation. Layers too thin to test (less than I.5 inch for 4 inch diameter specimen or 3 inches for 6 inch diameter specimen), as well as any thin surface treatments, shall be removed and discarded. However, 6 inch diameter specimens with thickness less than 3 inches but greater than I.5 inch, shall be reduced to a 4 inch diameter specimen and tested where possible. A test specimen shall consist of a single pavement material or layer greater than I.5 inches in thickness. The desired thickness for testing is approximately 2.5 inches for a 4 inch diameter specimen and 3.75 inches for a 6 inch diameter specimen. If the thickness of a particular AC layer scheduled for testing is one inch or more greater than the desired testing thickness, then the specimen to be C-8

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used for testing shall be obtained from the middle of the AC layer by sawing the specimen. If the thickness of a core from an AC layer is between I .S and 4 inches for a 4 inch diameter specimen and between 3 and 4.5 inches for a 6 inch diameter specimen, and has relatively smooth front and back faces then no sawing is required and the specimen for this layer may be tested as is. 6.3 6.4 7. PROCEDURE 7.! General Diametral Axis - Marking of the diametral axis to be tested shall be done using a suitable marking device as described in section 5.6. The axis shall be parallel to the traffic direction symbol (arrow) or "T" marked during the field coring operations. This diametral axis location can be rotated slightly, if necessary, to avoid contact of the loading strips with abnormally large aggregate particles or surface voids; or to avoid the mounting of the vertical EVDT over large surface voids. Rotation of test axis is also required if the surfaces to be loaded taper by more than .005 inch from parallel. Finally, the mid-thickness of the specimen shall be marked if necessary, to aid in centering the specimen on the loading strips. The thickness (t) of each test specimen shall be measured to the nearest 0.01 inch (0.25 mm) prior to testing. The thickness shall be determined by averaging four measurements located at ~J4 points around the sample perimeter, and 1/2 to ~ inch in from the specimen edge. The diameter (D) of each test specimen shall be determined prior to testing to the nearest 0.01 inch (0.25 mm) by averaging diametral measurements. Measure the diameter of the specimen at mid-height along (~) the axis parallel to the direction of traffic and (2) the axis perpendicular (90 degrees) to the axis measured in (~) above. The two measurements shall be averaged to determine the diameter of the test specimen. The asphalt cores shall be placed in a controlled temperature cabinet/chamber and brought to the specified test temperature. Unless the core specimen temperature is monitored in some manner and the actual temperature known, the core samples shall remain in the cabinet/chamber for a minimum of 24 hours prior to testing at 41F (5C) and 77F (25C). Specimens shall be held at 104F (40C) for a minimum of three hours, but not exceeding six hours prior to testing. (a) Determine the tensile strength of the test specimens at 77 ~ 2F using the procedure described in Attachment A to SHRP Protocol P07. (b) The test speciments) designated for resilient modulus testing shall be brought to the first test temperature (41 ~ 2F) as specified in section 7.! . C-9

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The procedure described in section 7.1 shall be completed to bring the test specimens to the remaining desired test temperatures (77 +2F, 104 2F). 7.2 Alignment anti Specimen Seating At each temperature, position the test specimen so that the mid-th~ckness mark on the test specimen is located in the line of action of the actuator shaft or alternately, ascertain that the specimen is centered exactly between end markings on loading strips. The diametral markings are then used to ensure that the specimen is aligned from top to bottom and front to back. The alignment of the front face of the specimen can be checked by ensuring that the diametral marking is centered on the top and bottom loading strips. With the use of a mirror, the back face can be similarly aligned. The electronic measuring system shall be adjusted and gains set as necessary. Prior to testing, zero the extensometers and the surface-mounted EVDT. An initial negative offset might be necessary if high gain is being used andJor there is a possibility of exceeding the range of voltage otherwise. The contact surface between the specimen and each loading strip is critical for proper test results. Any projections or depressions in the specimen to strip contact surface which leave the strip in non-contact condition over a length of more than 0.75 inches after completion of load conditioning stage, shall be reason for rotating the test axis or rejecting the specimen. If no suitable replacement specimen is available, test shall be conducted on the available sample and the situation documented. Preconditioning Preconditioning and testing shall be conducted while the specimen is located in a temperature-controlled cabinet meeting the requirements of section 6.3. 7.3.1 Selection of the applied loads for preconditioning and testing at the three temperatures is based on the indirect tensile strength, determined as specified in Attachment A to the SHRP Protocol P07. Tensile stress levels of 30, 15, and 4 percent of the tensile strength measured at 77F are to be used in conducting the test at temperatures of 41 ~ 2, 77 ~ 2, and 104 2F, respectively. Specimen contact loads specified in section 1.5 (f) shall be maintained during testing. 7.3.2 The sequence of resilient modulus testing shall consist of initial testing at 41F, followed by intermediate testing at 77F and final testing at 104F. The test specimens shall be brought to the specified temperature prior to each test, in accordance to section 7. I. The computer generated waveform shall be as closely matched as possible by adjusting the gains. The number of load applications to be applied depend upon the test temperature and the recommended number are 100, 100, and 50 for 41, 77, and 104F respectively. However, the minimum number of load C-10

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7.4 7.5 applications for a given situation must be such that the resilient modulus deformations are stable (section 7.5.~. When, using more preconditioning cycles, the number of preconditioning cycles shall be recorded and the reason documented. Also, if specimen has to be realigned, or when preconditioning has to be stopped for any other reason, sufficient time should be given to the specimen for relaxation before resuming the test. Both the horizontal and vertical deformations shall be monitored during preconditioning. If total cumulative vertical deformations greater than 0.015 inch for 41F, 0.03 inch for 77F and 104F occur, the applied load shall be reduced to the minimum value possible and still retain adequate deformations for measurement purposes. If use of smaller load levels are not adequate for measurement purposes, discontinue preconditioning end generate 10 load pulses for resilient modulus determination, and so indicate on the test report. Testing At the end of preconditioning at a specific test temperature, the resilient modulus shall be conducted as specified below. 7.5.! Record measured deformation as specified in section 7.6 of this protocol as soon as preconditioning is over (the load pulses are to be applied continuously through preconditioning and data collection for resilient modulus). Four of the last five cycles being utilized for resilient modulus calculations shall be within ~ 5% of the average resilient modulus value. 7.5.2 After the specimenfs) have been tested at a specific test temperature, bring the specimen to the next higher temperature in accordance with section 7. and repeat section 7.3.2 through section 7.5. ~ of this protocol. 7.5.3 After testing is completed at 104F, the specimen shall be brought to a temperature of 77 ~ 2F and an indirect tensile strength test conducted on the test specimen as specified in Attachment A of SHOP P07. Measure and record the recoverable horizontal and vertical deformations over the last 5 loading cycles of the total applied load pulses. One loading cycle consists of one load pulse and a subsequent rest period. The resilient modulus will be calculated and reported for each cycle using the equations in section 9 of this protocol. An average resilient modulus shall be obtained by calculating an average of the resilient modulus values for the last 5 load cycles. If one or more individual modulus value varies from the average by more than 15%, the value with the greatest deviation shall be omitted from the average. If a second individual modulus value varies by more than 15% from the average of the four remaining values than the test shall be rerun. If the variation of individual modulus value is less than ~ 5% from the average than the average of the four remaining values shall be reported. The variation from the average is calculated as follows: % Variation = ((MRi-MRa)/MRa)100 C-11

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where MR; = InJiV;JUa! resilient modulus value, and MRa = Average resilient modulus value. 7.7 Additionally, the cumulative horizontal and vertical deformation shall be determined as per Attachment C of the S`IRP P07 Protocol. 8. QUALITY ASSURANCE/QUALITY CONTROL 8.! Prior to the start of resilient modulus testing each week, the laboratory testing personnel shall perform testing on one or more of in-house QA/QC specimens (L`ucite, Polyethylene and Teflon) specimens to verify the system response for each test temperature to be used during the week. The synthetic specimens shall be tested at a temperature of 77F, at one rest period (0.9 sec.) on one axis and at three load levels. The synthetic specimens for weekly QA/QC have been selected to provide a response similar to the expected asphalt concrete specimen response at a given temperature as follows: - response similar to asphalt concrete testing at 41 F Polyethylene - response similar to asphalt concrete testing at 77F Teflon - response similar to asphalt concrete testing at 104F If AC resilient modulus testing is to be performed at all three temperatures In a given week, then all three samples shall be tested. If testing is to be conducted only at 41F for that week, then the Lucite specimen shall be tested at 77F to verify system response. If testing is to be conducted only at 77F that week, then the Polyethylene specimen shall be tested at 77F to verify system response. And, if testing is to be conducted only at 1 04F that week then the Teflon specimen shall be tested at 77F to verify system response. However, QAJQC testing shall be done whenever alignment of the loading system may have changed. The specimens shall be tested as follows: Sail.! The specimen shall be located in a temperature-controlled cabinet meeting the requirements of section 5.3 and at a temperature of 77F. The applied loads for preconditioning and testing for the synthetic specimens are defined below: S.~.2 The test specimen shall be preconditioned along the proper axis prior to testing by applying a minimum of 30 cycles of the specified haversine- shaped load pulse of 0. ~ second duration with a rest period of 0.9 second. Load level 2 specified for the synthetic specimens in section 8.! .! will be used for preconditioning. The computer generated wave form shall be matched as closely as possible by adjusting gains and preconditioning C-12

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shall continue until the horizontal deformations are stable and appear to be uniform. S.~.3 For each synthetic material, apply a minimum of 30 load pulses (each 0.1 second load pulse has a rest period of 0.9 seconds) and record measured deformations as specified in section 7.6 of this protocol. Perform the QA/QC testing by preconditioning a synthetic specimen at load level 2, and then testing at levels 1, 2, and 3 respectively. To verify the system response the deformation values shall fall within prescribed limits that will be set by testing across various well-equipped laboratories across the country. S.2 The results from the QA/QC testing shall be stored as a permanent record of the system response to obtain the system fingerprint. If all the synthetic specimens have not been tested for each set of 100 resilient modulus tests, QA/QC testing shall be performed on the remaining synthetic specimens in order to verify the system response. 9. CALCULATIONS The following equations are intended for the calculation of either instantaneous or total values depending upon whether instantaneous or total deformation values are used. Consider horizontal deformation as positive and vertical deformation as negative The load value is assumed to be positive. 9.! where, it= ~v= ~. _ Poisson's ratio: Poisson's ratio shall be calculated from the vertical and horizontal deformation values by the use of the following equation: 1.9345-O.2699- ~ =. ah 0.4309+ V ah instantaneous or total Poisson's ratio, the recoverable vertical deformation measured over a gage length equal to three quarters of the diameter of the specimen, inches, and the recoverable horizontal deformation measured over the horizontal diameter ofthe specimen, inches. C-13

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The calculated Poisson's ratio shall be subject to the following ranges: 4 ~ F: 0. ~ -0.3 77F: 0.25-0.45 104F: 0.4-0.5 The upper or lower limits may be used for resilient modulus calculation, depending upon whether the calculated Poisson's was greater than the upper limit or tower than the lower limit, respectively. However, when in doubt about the validity of the calculated Poisson's ratio, the calculated values shall be reported but the following values shad! be assumed for purposes of resilient modulus calculation: 41F: 0.2 77F: 0.35 104F: 0.5 When the calculated Poisson's ratio is outside of the ranges defined above, the calculated values shall be reported and a visual inspection of the specimen should be made to study the deformation in shape and/or presence of cracks due to damage, and so reported. When the resilient modulus test is being done to evaluate the deterioration in condition of the pavement, initial values of calculated Poisson's ratio (at the beginning of pavement life), if available, shall be used for resilient modulus calculations. In case of unavailability, assumed Poisson's ratios as defined above shall be used. However, Poisson's ratio shall also be calculated, and can be compared to give another estimate of the deterioration or damage. 9.2 Resilient modulus: The resilient modulus can then be calculated from the Poisson's ratio, as obtained from section 9.l, and the recoverable horizontal deformation (instantaneous or total) according to the following equation. P MR= (0.2699+~) Act where, MR = instantaneous or total resilient modulus, psi, C-14

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ah - recoverable horizontal deformation, inches, thickness of the specimen, inches, Pcyclic = PmaX- Pcontact . cyclic load applied to the specimen, Ibs., Pmax = maximum applied load, Ibs. Pcontac~- contact load, Ibs., and 11 = 10. REPORT instantaneous or total Poisson's ratio. 10.! The following general information shall be recorded: 10.~.! Sample Identification. 10.~.2 Average thickness of the test specimen (t), to the nearest 0.01 inch (as per section 6.4~. 10.13 Average diameter of the test specimen (D), to the nearest 0.01 inch (as per section 6.5~. 10.~.4 Indirect tensile strength (initial), to the nearest psi.; from a comparable test specimen used to select the stress (or load) level for the testing. 10.~.5 Indirect tensile strength (final), to the nearest psi; for the test specimen after the resilient modulus test has been completed. 10.~.6 Comments: The following (and additional, if so required) comments should be recorded, when relevant. (a) (b) (c) If sawing was required for core specimens. If the specimen was skewed (either end of the specimen departed from perpendicularity to the axis by more than 0.5 degrees or I/8 inch in 12 inches), as observed by placing the specimen on a level surface and measuring the departure from perpendicularity. If a "dummy" specimen was used to monitor the temperature. If not, the time specimen was maintained at the test temperature in the environmental chamber. C-15

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(~) If tests could not be completed at all temperatures due to damage/failure of test specimen. (e) If the projections/depressions on the test surface were higher or deeper than 1/16 inch and the specimen was tested as no replacement specimen was available. Record the projections/depressions in such a case. If for core specimens, no traffic direction was marked, or if test was not performed on the marked axis due to some reason. 10.2 The following information shall be recorded at each test temperature: 10.2.! Instantaneous Resilient Modulus: (a) The vertical load levels (Pcyc~ic) (b) The contact load (PContact) used over the last 5 loading cycles for each test temperature. (c) Instantaneous recoverable horizontal and vertical deformations measured over the last five cycles. (~) The calculated instantaneous Poisson's ratio (pi) over the last S loading cycles for each test temperature. (0 The calculated instantaneous resilient modulus (Mu) over the last 5 loading cycles for each test temperature. The average calculated instantaneous Poisson's ratio and instantaneous resilient modulus for the last 5 load cycles and standard deviation calculated at each test temperature. If any one modulus value varies from the average by more than 15%, it shall be omitted from the average calculation. However, all five values shall be reported and those not included in the average should be noted in the general remarks. 10.2.2 TotaIResilient Modulus: (a) The vertical load levels (PCyc~ic). (b) The contact toad (PCon~ac') used over the last 5 loading cycles for each test temperature. (c) Total recoverable horizontal and vertical deformations measured over the last five cycles. C-16

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(d) The calculated total Poisson's ratio (I over the last 5 loading cycles for each test temperature. The calculated total resilient modulus (Ma) over the last 5 loading cycles for each test temperature. The average calculated total Poisson's ratio and total resilient modulus for the last 5 load cycles and standard deviation calculated at each test temperature. If any one modulus value varies from the average by more than 15%, it shall be omitted from the average calculation. However, all five values shall be reported and those not included in the average should be noted in the general remarks. 10.23 Permanent Horizontal and Vertical Deformations: (a) The number of preconditioning cycles used for each test temperature. (b) The cumulative permanent vertical deformation measured, including the preconditioning cumulative deformation and the resilient modulus testing cumulative deformation. (d) (g) (h) The cumulative permanent horizontal deformation measured, including the preconditioning cumulative deformation and the resilient modulus testing cumulative deformation. The total number of load cycles conducted during the test. This includes the number of cycles for preconditioning and those cycles conducted for the determination of resilient modulus. The cumulative vertical deformation measured after preconditioning prior to initiation of resilient modulus testing. The cumulative horizontal deformation measured after preconditioning prior to initiation of resilient modulus testing. The cumulative permanent vertical deformation per load cycle. The cumulative permanent horizontal deformation per load cycle. C-17

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