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105 APPENDIX C Microsurfacing Example Contract Clauses, Specifications, and Checklists This Appendix contains copies of all the specifications, warranty clauses, etc., that are noted in the body of the report. STATE OF OHIO DEPARTMENT OF TRANSPORTATION SUPPLEMENTAL SPECIFICATION 881 MICRO-SURFACING WITH WARRANTY July 13, 1999 881.01 General 881.02 Warranty Bond 881.03 Materials, Mixture, Equipment, and Quality Control 881.04 Surface Preparation 881.05 Test Strip 881.06 Single Course Construction 881.07 Multiple Course Construction 881.08 Finished Pavement 881.09 Warranty Items and Work 881.10 Appeal Process 881.11 Basis of Payment 881.01 General. This work shall consist of constructing a cold laid polymer modified emulsified asphalt pavement course to fill ruts or provide one or more courses for existing pavements in reasonably close conformity with the lines shown on the plans or established by the Engineer and warrant it for 3 years. 881.02 Warranty Bond. When the successful Bidder provides the Department with the performance and payment bonds specified in 103.05, the successful Bidder shall also furnish a maintenance bond for a 3 year period in an amount equal to 75 percent of the contract amount. The Surety that underwrites the maintenance bond is required to have an A.M. Best rating of "A -" or better. The cost of the maintenance bond shall be included in the pay item for the premium for the contract performance and payment bonds. The effective date of the maintenance bond is the date the Department's Form C-85 is issued for the pavement. The issuance of Form C-85 for the pavement shall occur within 30 days after all of the pavement items, including all pavement markings, are completed and the pavement is open to traffic in its permanent pattern. After Form C-85 is issued, the Department will notify the Surety and will establish all final quantities for the project and the project will be finalized using standard procedures. The maintenance bond expires 3 years after the issuance of Form C-85. The Contractor shall maintain the liability insurance specified in 107.14, insuring against Contractor or Contractor authorized operations negligently performed during the warranty period. This insurance shall be in effect throughout the warranty period. A copy of the Certificate of Insurance shall be sent to the District each year. 881.03 Materials, Mixture, Equipment, and Quality Control. The material shall meet or exceed the requirements of 406.02. The mixture used shall meet or exceed the requirements of 406.03. The equipment used for micro-surfacing shall be self-contained, self-propelled, continuous loading units designed for this purpose. A minimum of two weeks before the start of production, the Contractor shall submit their material quality control plan and final mix design to the District Engineer of Tests and Laboratory. During production, any changes in the mix design shall also be submitted. These submittals are for verification of the above minimum requirements. 881.04 Surface Preparation. Surface preparation shall meet the requirements of 406.08 except as follows: The Contractor is responsible for all surface preparation including cleaning, removal of any paint or plastic markings, tack coat and any other work that may effect the performance of micro-surfacing. This surface preparation shall be included in the bid price of the 881. All visible joints and cracks longer than 2 feet (600 mm) in length shall be sealed in accordance with 825.04. This crack seal shall be included in the bid price for 881. 881.05 Test Strip. The Contractor shall construct a test strip to be evaluated by the Engineer. This test strip shall be 1000 feet (300 meters) long and consist of all of the application courses specified. The test strip shall be constructed at the same time of day or night the full production will be applied and may be constructed in 2 days or nights when multiple course applications are specified. The Engineer will evaluate the completed test strip after 24 hours of traffic to determine if the mix design is acceptable. Full production may begin after the Engineer accepts a test strip. If accepted, the cost of the test strip shall be paid for at the bid price for 881. The test strip requirements will be waived if the following conditions are met: 1. The micro-surfacing will not be applied after September 30 or before May 1; and 2. The Contractor has constructed a test strip in the same construction season that was accepted by the Department and utilized the same materials and mix design.
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106 881.06 Single Course Construction. The Contractor shall apply one course of microsurfacing mixture. The single course shall be completed using Gradation A aggregate applied at a minimum rate of 18 pounds/square yard (9.8 kg/m²) of dry aggregate or Gradation B aggregate applied at a minimum rate of 20 pounds/square yard (11 kg/m²) of dry aggregate. 881.07 Multiple Course Construction. The Contractor shall apply at a minimum, two courses of micro-surfacing mixture, each applied separately. The pavement cross section shall be restored by rut filling and or one or more leveling courses. This cross section correction shall be applied to the driving lanes only, prior to the surface course, which shall be applied to the entire paving pass, which may include the shoulder as directed by the plans. The total combined minimum application rate of 30 pounds/square yard (16.3 kg/m²) of dry aggregate shall be applied. The Department may specify a single course micro-surfacing on the shoulders when directed by the plans. Pavement segments greater than 1000 feet (300 meter) in length, with an average rut depth that exceeds 0.5 inch (12 mm), shall be rut filled. The Contractor shall use a microsurfacing mix with Gradation B aggregate applied with an approved rut box for each designated wheel track. A clean overlap and straight edges shall be required between wheel tracks. Each rutted wheel track shall be over crowned to allow for proper consolidation by traffic. For each 1 inch (25 mm) of applied mix, an additional 0.125 to 0.25 inches (3 to 5 mm) crown is required for traffic consolidation. If the Contractor applies leveling courses to profile the pavement, a micro- surfacing mix with Gradation A or B aggregate shall be used. The final surface course shall be completed using Gradation A aggregate, applied at a minimum application rate of 16 pounds/square yard (9 kg/m²) of dry aggregate or a Gradation B may be used with a minimum application rate of 20 pounds/square yard (11 kg/m²) of dry aggregate. 881.08 Finished Pavement. Traffic shall not be allowed on the mixture until it has cured sufficiently to prevent pickup by vehicle tires. The new surface shall be capable of carrying normal traffic within one hour after application without any damage occurring. Filled ruts shall be able to sustain traffic within 2 hours after placement. The Contractor shall protect the new surface from potential damage at intersections and driveways. Any damage by traffic to the mixture shall be repaired by and at the Contractor's expense. The finished surface should be free from excessive scratch marks, tears, rippling, and other surface irregularities. The surface area shall not contain transverse ripples or longitudinal streaks of 0.2 inch (5 mm) or more in depth, as measured with a 10 foot (3 meter) straight edge. The surface area shall not exhibit tear marks greater than 0.5 inch (13 mm) wide and or 4 inches (100 mm) long, or a tear mark greater than 1 inch (25 mm) wid e and 3 inches (75 mm) long. The longitudinal construction joints and lane edges shall coincide with the proposed painted lane lines. Longitudinal joints shall be constructed with less than a 3 inch (75 mm) overlap on adjacent passes and no more than 0.5 inch (6.5 mm) overlap thickness as measured with a 10 foot (3 meter) straight edge. If applicable, place overlapping passes on the uphill side to prevent any ponding of water. Construct neat and uniform transverse joints with no more than a 0.2 inch (5 mm) difference in elevation across the joint as measured with a 10 foot (3 meter) straight edge. The edge shall be neat and uniform with no more than 2 inches (50 mm) of horizontal variance in any 100 feet (30 meters). The restored cross section of the pavement section between any edge line, lane line or center line as measured using a 10 foot (3 meter) straight edge transversely across the pavement shall not exceed 0.4 inches (10 mm), or 0.2 inches (5 mm) when measured with a 6 foot (1.8 m) straight edge. The preceding shall not apply to any pavement segment that is designed with a quarter crown cross slope or any area of the pavement within 1 foot (300 mm) of the edge line, lane line or center line. These cross section requirements do not apply to single course micro-surfacing. 881.09 Warranty Items and Work. The District Review Team (DRT) will review the pavement before June 1 each year during the warranty period to determine the performance of the micro-surfacing. Any areas of the pavement that do not meet the Threshold Levels specified in Table A, will have to be repaired by the Contractor. The District will notify the Contractor in writing of any required Warranty Work. Meeting the minimum requirements and guidelines of this specification are not to be construed as a warranty, expressed or implied, as to the materials properties and workmanship efforts required to meet the performance criteria specified.
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107 The Contractor shall supply all material and labor to perform the Warranty Work at no additional cost to the Department. All Warranty Work shall be performed with material meeting the requirements of 881.03. The Contractor shall certify the component materials and designed mix meet or exceed the requirements of 881.03. All Warranty Work shall be performed by August 31 of the same year as the review. If an appeal process uses the arbitration method, the District may revise the date for the completion of the Remedial Action for the appealed item. Any 1000 foot (300 meter) lane segment that has repairs or defects greater than 5 percent of the area shall be completely resurfaced with a full lane width of micro-surfacing meeting the requirements of 881.06 or 881.07. Only micro-surfacing shall be used for permanent repair and resurfacing areas. If the Department determines that immediate repairs are necessary, due to a potential hazard to the traveling public, the Department will notify the Contractor and establish a date that all repairs have to be finished. Temporary repairs may be performed using material approved by the Engineer. All temporary repairs shall be replaced with a permanent repair as soon as weather allows. The Contractor's construction traffic control for performing any work required or allowed by this specification during the warranty period shall be in accordance with current Department policy, the Ohio Manual of Uniform Traffic Control Devices for Streets and Highways, and subject to Department approval of the time the work will be performed. Any major change in Department construction traffic control policy will be considered a changed condition. 881.10 Appeal Process. The Contractor may appeal a finding of the DRT. Any appeal shall be submitted to the DCE, in writing, within 15 days after the written results of the DRT are given to the Contractor. The DCE will evaluate the Contractor's appeal. This evaluation will include reviewing the disputed area in the field and consulting with the Construction Section of the Office of Highway Management. The evaluation may also include reviewing test data, obtaining samples, or interviewing Department (District or Central Office) or Contractor employees. The DCE's determination will be issued in writing to the Contractor within 45 days after the DCE receives the appeal. If the Contractor disagrees with the DCE's determination, the Contractor may appeal the determination using an arbitration method acceptable to the Department. The Department will agree, in all cases, to arbitration in the manner in which those methods are practiced by the Department. If the Contractor selects arbitration, written notice of this approach must be made to the DCE within 15 days of receipt of the DCE's deter mination. After written notice has been provided, the parties shall agree in writing to the Arbitrator and agree to share equally the fees of the Arbitrator. After the Arbitrator is given notice to proceed, the Arbitrator shall conduct an investigation and issue a determination within 45 days. The Arbitrator's determination will be limited to determining whether or not the pavement distress is or is not the fault of the Contractor. 881.11 Basis of Payment. The method of measurement shall be on an area basis [square yard (square meter)] in accordance with 406.12. The accepted quantities of microsurfacing will be paid for at the contract price for: Item Unit Description 881 Square yard (square meter) Micro-surfacing with warranty, single course 881 Square yard (square meter) Micro-surfacing with warranty, multiple course
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108 Missouri DOT Method Specification SECTION 413.10 MICRO-SURFACING 413.10.1 Description. This work shall consist of producing and placing a mixture of cationic polymer-modified asphalt emulsions, mineral aggregate, mineral filler, water, and other additives as needed at locations shown on the plans or as directed by the engineer. 413.10.2 Material. All material shall be in accordance with Division 1000, Material Details, and specifically as follows: Item Section Emulsified Asphalt 1015 Aggregate 1002 4126.96.36.199 Aggregate. 4188.8.131.52.1 The mineral aggregate shall be flint chat from the Joplin area, an approved crushed porphyry or an approved crushed steel slag. Blast furnace slag may be used from sources with a documented history of satisfactory use and that have been previously approved by MoDOT for use in micro-surfacing. For non-traffic areas such as shoulders, the mineral aggregate may be crushed limestone or crushed gravel in accordance with Sec 1002.1. The aggregate shall be free of cemented or conglomerated material and shall not have any coating or detrimental material. 4184.108.40.206.2 Blends of approved aggregate may be supplied provided: (a) The individual aggregates are reasonably uniform in gradation and other qualities. (b) The aggregates are uniformly blended with designated proportions into a separate stockpile prior to use. Aggregate may be blended directly into the supply truck provided the blending device has been calibrated, gate settings are unchanged, and belt samples indicate material gradation compliance. (c) The proportion is not changed from the job mix formula during the course of placement. 4220.127.116.11.3 The final aggregate, or blend of aggregates, shall be in accordance with one of the following gradations. In addition, the aggregate shall be ± 5 percent of the designated job mix gradation for all plus No. 200 (75 µm) material and within ± 2 percent for the minus No. 200 (75 µm) material. 418.104.22.168.4 The final aggregate mixture shall have no oversize material when deposited at the stockpile site. If the stockpile area contains any particles exceeding the specified maximum sieve, all aggregate shall be screened again as the aggregate is loaded into the final placement machine. 422.214.171.124 Mineral Filler. Mineral filler shall be Type 1 Portland cement or hydrated lime, and shall be free of lumps or any other deleterious material. 4126.96.36.199 Water. Water shall be potable and free of harmful soluble salts. 4188.8.131.52 Additives. Any other material added to the mixture or to any of the component materials to provide the required properties shall be supplied by the emulsion manufacturer. 4184.108.40.206. Material Acceptance. All aggregate shall be sampled, tested and approved by the engineer prior to use. Portland cement and hydrated lime may be accepted for use based on visual examination. 413.10.3 Job Mix Formula. The manufacturer of the emulsion shall develop the job mix formula and shall present certified test results for the engineer's approval. The job mix formula shall be designed in accordance with the International Slurry Surfacing Association (ISSA) recommended standards by an ISSA recognized laboratory. Mix acceptance will be subject to satisfactory field performance. The job mix formula, all material, the methods and the proportions shall be submitted for approval prior to use. Proportions to be used shall be within the limits provided in the table below. If more than one aggregate is used, the aggregates shall be blended in designated proportions as indicated in the job mix formula, and those proportions shall be maintained throughout the placement process. If aggregate proportions are changed, a new job mix formula shall be submitted for approval.
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109 4220.127.116.11 All Types. The minimum dry mass per unit area will be based on a bulk specific gravity (BSG) of 2.65. In the event that crushed steel slag aggregate is used as a part of the blended aggregate or as the entire aggregate, the BSG of the final aggregate blend shall be determined and shown as part of the job mix formula criteria. If the BSG is different from 2.65 by more than 0.05, the above minimum masses shall be adjusted by dividing the specified unit mass by 2.65 and multiplying by the new BSG. (For example, for a new BSG = 3.15, the new minimum would be 3.15(10.8/2.65) = 23.8 lbs./sy (12.8 kg/m2)). These adjusted values shall be designated on the job mix formula and will apply in the field. 418.104.22.168.1 Type II. For Type II, if a specified thickness will be required, the amount of mineral aggregate per square yard (m2) shall be increased as necessary to obtain the thickness. 422.214.171.124.2 Type III. When specified, Type III shall be applied in two passes of approximately equal quantities, the first of which shall be to fill depressions and level the surface for the final pass. 4126.96.36.199.3 Type IIIR. For Type IIIR mixes, there will be no minimum or maximum unit quantities. The contractor shall make the determination as to the amount necessary, except all depressed areas shall be filled level as specified. Type IIIR may be applied in more than one pass at the contractor's expense. Type IIIR shall not be added to Type II or Type III applications in the field, but shall be a separate application. 413.10.4 Equipment. 4188.8.131.52 Mixing Equipment. The micro-surfacing mixture shall be mixed and laid by a self-propelled mixing machine. The mixing machine shall be able to accurately deliver and proportion the aggregate, mineral filler, water, additive and emulsion to a revolving multiblade dual mixer and to discharge the thoroughly mixed product. The machine shall have sufficient storage capacity for all components to maintain an adequate supply to the proportioning controls. 4184.108.40.206.1 Individual volume or weight (mass) controls for proportioning each item to be added to the mix shall be provided. Each material control device shall be calibrated and properly marked. The calibration shall be approved by the engineer prior to proportion. Each device shall be accessible for ready calibration and placed such that the engineer may determine the amount of each material used at the time. 4220.127.116.11.2 The mixing machine shall be equipped with a water pressure system and nozzletype spray bar to provide a water spray to dampen the surface when required immediately ahead of and outside the spreader box as required. No free flowing water shall be present. 418.104.22.168 Spreading Equipment. The micro-surfacing mixture shall be spread uniformly by means of a mechanical-type spreader box attached to the mixer. The spreader box shall be equipped with paddles or augers to agitate and spread the material uniformly throughout the box. The paddles or augers shall be designed and operated so all the fresh mix will be agitated to prevent the mixture from setting up in the box, causing side buildup and lumps. 422.214.171.124.1 The spreader box used for surface course construction shall be equipped with flexible seals in contact with the road to prevent loss of mixture from the box. The box shall be equipped with devices to adjust the thickness or grade of the surface and shall have a squeegee strike-off rear plate. 4126.96.36.199.2 A secondary strike-off shall be provided to improve surface texture. The secondary strike-off shall have the same adjustments as the spreader box. 4188.8.131.52.3 The spreader box used for rut-filling shall have two metal strike-offs, angled from each side toward the center at approximately 45 degrees. Interrupted flight augers shall be used ahead of the first strike-off plate to spread the mix and maintain laminar flow. The second strike-off plate shall be adjusted to produce the desired grade and depth. The first strike-off and augers shall be adjustable up and down in order to maintain a fairly uniform flow or roll of material in front of the second strike-off. A rubber squeegee shall be attached to the adjustable metal plate at the rear of the spreader box, behind the second strike-off, to texture the surface. The adjustable metal plate shall have sufficient clearance not to affect the grade established by the second strike-off. 413.10.5 Construction Requirements. 4184.108.40.206 Test Strip. A test strip 500 feet (150 m) long and the width of one lane shall be provided. The test strip will be evaluated for 24 hours after placement and will be subject to approval from the engineer before any further production. If unsatisfactory, the test strip shall be removed and another strip placed for evaluation at the contractor's expense. 4220.127.116.11 Surface Preparation. The surface shall be thoroughly cleaned of all vegetation, loose material, dirt, mud, and other objectionable material and shall be pre-wetted as required immediately prior to application of the micro-surfacing. All pavement marking shall be removed, maintained, and compensated for in accordance to Sec 620. 418.104.22.168 Application. The micro-surfacing mixture shall be spread to fill cracks and minor surface irregularities, and shall leave a uniform surface. No lumping, balling or unmixed aggregate will be permitted. Longitudinal joints shall be
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110 placed on lane lines. Excessive overlap will not be permitted. The finished micro-surfacing shall have a uniform texture free of scratches, tears and other surface irregularities. The contractor shall repair the surface if any of the following conditions exist: (a) More than one surface irregularity that is 1/4 inch (6 mm) or wider and 10 feet (3 m) or longer in any 100-foot (30 m) section of the micro-surfacing. (b) More than three surface irregularities that are 1/2 inch (12 mm) or wider and more than 6 inches (150 mm) long in any 100-foot (30 m) section of the micro-surfacing. (c) Any surface irregularity that is one inch (25 mm) or wider and more than 4 inches (100 mm) long. The finished longitudinal and transverse joints in the micro-surfacing shall be complete and uniform. 422.214.171.124.1 The contractor shall repair joints if any of these conditions exist: (a) Build-up of micro-surfacing material at the joints. (b) Uncovered areas at the joints. (c) Longitudinal joints with more than 1/2 inch (12 mm) vertical space between the surface and a 4-foot (1.2 m) straightedge placed perpendicular to the joint. (d) Transverse joints with more than 1/4 inch (6 mm) vertical space between the surface and a 4-foot (1.2 m) straightedge placed perpendicular to the joint. 4126.96.36.199.2 The edges of the micro-surfacing shall follow the centerline, lane lines, shoulder lines and curb lines. The edges shall be repaired if the edges vary more than 3 inches (75 mm) from a 100-foot (30 m) straight line or from a 100- foot (30 m) arc on a curved section. The repaired surface shall be dense with a uniform texture. 4188.8.131.52.3 Any successive passes shall be separated such that each layer placed undergoes approximately 12 hours of traffic for compaction and curing. 4184.108.40.206.4 Type IIIR applications to raise shoulders or fill ruts shall be applied with the rut spreader box, and the contractor shall place a strip as designated in the contract docu ments to raise an area to match the surroundings. Rutting or traffic-bearing applications, excluding shoulders, shall be crowned 1/8 to 1/4 inch per inch (3 to 7 mm per 25 mm) of depth, to allow for compaction. Shoulder applications shall drain and slope uniformly downward to the shoulder point. A Type II or Type III application may follow as a surface course if specified in the contract documents. 4220.127.116.11.5 Micro-surfacing shall not be placed over steel expansion plates. 418.104.22.168.6 When micro-surfacing is placed on concrete, a tack coat shall be applied first in accordance with Sec 407 and shall be given adequate time to break. 422.214.171.124.7 The micro-surfacing shall permit traffic operations on a 1/2 inch (12 mm) thick surface within one hour after placement at 75°F (25°C) and 50 percent humidity. 4126.96.36.199 Weather Limitations. Micro-surfacing shall not be placed when either the air temperature or the temperature of the surface on which the mixture is to be placed is below 50°F (10°C), when it is raining, or when there is a chance of temperatures below 32° F (0° C) within 24 hours after placement. Temperatures shall be obtained in accordance with MoDOT Test Method TM 20. 4188.8.131.52 Repair of Damaged Areas. Any traffic-damaged, marred areas or deficiencies as defined in Sec 4184.108.40.206 shall be repaired by the contractor at the contractor's expense. 4220.127.116.11 Incidental Construction. Areas that cannot be reached with the mixing machine shall be surfaced using hand squeegees to provide complete and uniform coverage. Utilities shall be protected from coverage by a suitable method. Work at intersections shall be done in stages, or blotter material shall be used to allow crossing or turning movements. Regardless of the method, no marred sections will be permitted. 413.10.6 Method of Measurement. Final measurement of completed Type II and Type III surface will not be made except for authorized changes during construction, or where appreciable errors are found in the contract quantity. Where required, measurement of Type II, Type III and Type IIIR micro-surfacing, complete in place, will be made to the nearest square yard (square meter). Final measurement of Type IIIR surface may be made as necessary to determine the actual areas placed. Field measurement will be based on the estimated width and length dimensions necessary to bring a designated area to a level plane, and not necessarily for the full rutted area. The revision or correction will be computed and added to or deducted from the contract quantity. 413.10.7 Basis of Payment. The accepted quantities of micro-surfacing will be paid for at the contract unit price for each of the pay items included in the contract. No additional payment will be made for removing and replacing test strips.
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111 Checklists: Suggested Field Considerations for Microsurfacing The following is an extract from Chapter 8: Micro-Surfacing of the NHI 2007 Pavement Preservation Treatment Construction Guide. The following tables are guides to the important aspects of performing a micro-surfacing project. The tables list items that should be considered to promote a successful job. Thorough answers to these questions should be determined, as required, before, during, and after construction. The appropriate staff to do this will vary by job type and size. Some topics may need attention from several staff members. The field supervisor should understand its contents. The tables are not intended to be a report but to draw attention to important aspects and components of the micro-surfacing project process. Some information may be product-specific and should be contained in the agency's relevant standard specifications, special standard provisions, or special provisions. Preliminary Responsibilities Is the project a good candidate for micro- Is crack sealing needed? surfacing? How much bleeding or flushing exists? Project Should a micro-surfacing seal be used? Is the pavement raveling? Review What is the depth and extent of any rutting? What is the traffic level? How much and what type of cracking exists? Is the base sound and well drained? Have the project bid/plan quantities been reviewed? Bid specifications. Construction manual. Document Mix design information. Traffic control plan (TCP). Review Special provisions. Material safety data sheet Has a full mix design and compatibility test been Does the aggregate meet all specifications? completed? Is the aggregate clean and free of deleterious materials? Materials Is the binder from an approved source (if Is the aggregate dry? Checks required)? Is the emulsion temperature within application Has the binder been sampled and submitted for temperature specifications? testing? Pre-Seal Inspection Responsibilities Surface Preparation Is the surface clean and dry? Have all pavement distresses been repaired? Has the existing surface been inspected for drainage problems?
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112 Equipment Inspection Considerations Broom Are the bristles the proper length? Rollers Do the roller tire pressures comply with the Can the broom be adjusted vertically to (if used) manufacturer's specification? avoid excess pressure? What type roller will be used on the project (pneumatic-tired roller recommended)? Do the roller tire size, rating, and pressures comply with manufacturer's recommendations? Is the pressure in all tires the same? Do all tires have a smooth surface? Calibration of Has each machine been calibrated with the Stockpile Is the stockpile site well drained and clean? Equipment project's aggregate and emulsion? Does the Contractor have all of the Who carried out calibration and what equipment required at the stockpile site documentation has been provided? (loaders, tankers, and so on)? Micro- Is the machine fully functional? Equipment Is all equipment free of leaks? surfacing Has the machine been calibrated for this for Are Flow boys or other nurse units clean Machine project's aggregate and certified. Is the continuous and functional? spreader rubber clean and not worn? run Are there enough units to allow continuous Is the texture rubber clean and set at the operations running with minimal stops for cleaning right angle? box rubbers? Are all paddles in the pug mill intact? Is the spreader box clean and is it a micro- surfacing type box? Site Considerations Have air and surface temperatures been checked at the coolest location on the project? Do air and surface temperatures meet agency requirements? Weather Are adverse weather conditions expected? (High temperatures, humidity, and wind will affect how Requirements long the emulsion takes to break.) Is application of the micro-surfacing postponed if rain is likely? Are freezing temperatures expected within 24 hours of the completion of any application runs? Do the signs and devices used match the traffic control plan? Does the work zone comply with the agency's requirements? Are flaggers holding the traffic for reasonable periods of time? Traffic Control Are unsafe conditions, if any, promptly reported to a supervisor (contractor or agency)? Does the pilot car lead traffic slowly, 40 kph (24 mph) or less, over fresh micro-surfacing? Are signs removed or covered when they no longer apply?
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113 Application Considerations Have agency guidelines and requirements been followed? Have rut filling and leveling course application rates been calculated or estimated separately? Determining Has a full mix design been done? Application Is more material applied to dried-out and porous surfaces? Rates Is more material applied on roads with low traffic volumes? Is less material applied to smooth, non-porous, and asphalt-rich surfaces? Has moisture content been adjusted when calculating the application rate? Project Inspection Responsibilities Has a satisfactory test strip been done? Have field tests been carried out and are the results within specification? Are enough trucks on hand to provide a steady supply of material for the slurry machine? Does the application start and stop with neat, straight edges? Will an edge box be used? Is a rut box is used for ruts deeper than 12 mm (1/2")? Is a leveling course used with a steel strike-off for ruts less than 12 mm (1/2")? (Two courses are used where rut filling or leveling is employed.) Does the application start and stop on building paper or roofing felt? Micro-surfacing Are drag marks present due to oversize aggregate or dirty rubbers? Application Are rubbers cleaned regularly and at the end of each day? Does the machine follow a straight, even line with minimal passes to cover the pavement? Is the mix even and consistent? Are fines migrating to the surface? Is the application stopped as soon as any problems are detected? Does the application appear uniform? Does the surface have an even and uniform texture? Is the application rate checked based on amounts of aggregate and emulsion used? What is the time between spreading, foot traffic, and opening to vehicular traffic? Does rolling wait until the mat is stable? (Roller is 5-6 tonnes maximum) Rolling Is the entire surface rolled only once? Do the rollers travel slowly, 8-9 kph (5 mph) maximum? Are trucks staggered across the fresh seal coat to avoid driving over the same area? Do trucks travel slowly on the fresh seal? Truck Operation Are stops and turns made gradually? Do truck operators avoid driving over the micro-surfacing? Do truck operators stagger their wheel paths when backing into the paving unit? Is the meet line overlapped a maximum of 75 mm (3 in)? Longitudinal Do the spreader box runners avoid running on the fresh mat? Joints Are the meet lines at the center of the road, center of a lane, or edge of a lane, not in the wheel paths? Do all applications begin and end on building paper? Transverse Is the mixture not too wet at start up? Joints Is the building paper disposed of properly? Does brooming begin after the micro-surfacing can carry traffic? Brooming Does brooming dislodge the micro-surfacing? Is the surface raveling? (Follow-up brooming should be done if raveling is high or if traffic is high.) Opening the Does the traffic travel slowly -- 40 kph (24 mph) or less over the fresh micro-surfacing? Microsurfacing Are reduced speed limit signs used when pilot cars are not used? to Traffic After brooming, have pavement markings been placed before opening to traffic? Has all loose aggregate been removed from the traveled way prior to opening to traffic? Clean Up Have all binder spills been cleaned up?
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114 Troubleshooting This section provides information to assist the maintenance personnel in troubleshooting problems with micro-surfacing, along with "dos and don'ts" that address common problems that may be encountered during the course of a project. The troubleshooting guide presented in Table associates common problems with their potential causes. For example, an unstable emulsion, too little water in the mix, incompatibility between the emulsion and the aggregate, and so on, may cause a slurry surface to delaminate. Trouble Shooting Microsurfacing Job Problems Problem Delayed Opening Breaks in Box Failure to Set Delamination Poor Coating Segregation to Traffic Whitish Flushes Brown Ravels Cause Emulsion · · · Emulsion unstable No No No No No No No Yes Yes Yes · · · · Emulsion too stable No No No No No No Yes Yes Yes Yes · Emulsion too hot No No No No No No No No No Yes · · · Too little emulsion No No No No No No No Yes Yes Yes · Too much emulsion No No No No No No No No No Yes Mix · · · Mix: Too many fines No No No No No No No Yes Yes Yes · · Mix: Too much cement No No No No No No No No Yes Yes · · · · Mix: Too little cement No No No No No No Yes Yes Yes Yes · · · Mix: Too little additive No No No No No No No Yes Yes Yes · · · · Mix: Too much additive No No No No No No Yes Yes Yes Yes · · · · · · Mix: Too much water No No No No Yes Yes Yes Yes Yes Yes · · · · · Mix: Too little water No No No No No Yes Yes Yes Yes Yes · · · · · · Mix: Aggregate/emulsion not compatible No No No No Yes Yes Yes Yes Yes Yes
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115 Conditions · · · · · Condition: Too hot No No No No No Yes Yes Yes Yes Yes · · · · Condition: Too cold No No No No No No Yes Yes Yes Yes · · · · · · · Condition: Rain No No No Yes Yes Yes Yes Yes Yes Yes · · Condition: High humidity No No No No No No No No Yes Yes Surface · · Surface: Fatty No No No No No No No No Yes Yes In addition to the troubleshooting guide, the table below contains some commonly encountered problems and their recommended solutions. Common Problems and Related Solutions Problem Solution Ensure the spreader box is correctly set up. Ensure the viscosity of the mix is not too high. Uneven Surface Wash Make adjustments so that the mix does not break too fast. Boarding Wait until the ambient temperature is lower. Use water sprays on the front of the spreader. Reduce the amount of water at start up. Poor Joints Use water spray if runners of spreader box are running on fresh material. Add cement and reduce additive so that the mix breaks and cures faster. Check aggregate to ensure the clay fines are not too high. Excessive Ravel Control traffic longer and at low speeds. Wait until fully cured before allowing traffic. Wait until mix is properly set before brooming or opening to traffic.