1、Designation: D7564/D7564M 09 (Reapproved 2015)Standard Practice forConstruction of Asphalt-Rubber Cape Seal1This standard is issued under the fixed designation D7564/D7564M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers asphalt-rubber cape seal, which isdefined as the application of an asphalt-rubber seal coat pl
3、acedonto an existing pavement surface, followed by the applicationof a conventional Type II or III slurry seal.NOTE 1An asphalt-rubber seal coat is also known as a stressabsorbing membrane (SAM) which consists of an asphalt-rubber mem-brane seal followed by the application of precoated aggregate chi
4、ps.1.2 An asphalt-rubber cape seal is commonly used to extendthe service life of low to medium trafficked and moderatelydistressed asphalt-surfaced pavements. The existing pavementcondition can be used to determine the application rates for theasphalt-rubber binder and aggregate as well as the aggre
5、gategradation. Pavements in relatively poor condition will requirea coarser aggregate with a higher binder application rate.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore,
6、eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to e
7、stablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC117 Test Method for Materials Finer than 75-m (No. 200)Siev
8、e in Mineral Aggregates by WashingC127 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Coarse AggregateC128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC131 Test Method for Resistance to Degradation of Small-Size Coarse
9、Aggregate by Abrasion and Impact in the LosAngeles MachineC136 Test Method for Sieve Analysis of Fine and CoarseAggregatesD946 Specification for Penetration-Graded Asphalt Cementfor Use in Pavement ConstructionD1139 Specification for Aggregate for Single or MultipleBituminous Surface TreatmentsD2196
10、 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational (Brookfield type)ViscometerD2419 Test Method for Sand Equivalent Value of Soils andFine AggregateD3381 Specification for Viscosity-Graded Asphalt Cementfor Use in Pavement ConstructionD3910 Practices for Design, Testin
11、g, and Construction ofSlurry SealD4791 Test Method for Flat Particles, Elongated Particles,or Flat and Elongated Particles in Coarse AggregateD5360 Practice for Design and Construction of BituminousSurface TreatmentsD5821 Test Method for Determining the Percentage ofFractured Particles in Coarse Agg
12、regateD6114 Specification for Asphalt-Rubber BinderD6373 Specification for Performance Graded AsphaltBinderD6433 Practice for Roads and Parking Lots Pavement Con-dition Index Surveys3. Significance and Use3.1 The procedure described in this practice is used todesign and construct an asphalt-rubber c
13、ape seal that willprovide a wearing course when subjected to low to mediumtraffic volumes and where the pavement distress is due toblock-type cracking resulting from pavement aging or reflec-tive cracking only (not where there are clear indications offatigue cracking due to repeated heavy axle loads
14、).NOTE 2Block cracking is defined in Practice D6433. See AppendixX1 for an example of block cracking due to aging.1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.24 onAsphalt Surface Treatments.Current ed
15、ition approved Jan. 1, 2015. Published February 2015. Originallyapproved in 2009. Last previous edition approved in 2009 as D7564/D7564M 09.DOI: 10.1520/D7564_D7564M-09R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
16、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Materials4.1 Asphalt-Rubber Seal Coat (or Stress AbsorbingMembraneSAM):4
17、.1.1 Asphalt CementThe asphalt cement for the asphalt-rubber seal coat should comply with the requirements ofSpecifications D946, D3381,orD6373. Asphalt cement gradeselection is based on considerations of local climatic and trafficconditions. The asphalt-rubber supplier should perform routineQ/C lab
18、oratory testing to ensure compatibility of the selectedasphalt cement with the requirements of Specification D6114.4.1.2 Asphalt-RubberThe asphalt-rubber binder consistsof an interacted blend of paving grade asphalt cement, groundrecycled tire rubber, and other additives as needed to conformto the r
19、equirements of Specification D6114.4.1.3 AggregateAggregate consists of crushed materialsconforming to the physical requirements of SpecificationD1139 for degradation, soundness, and deleterious substancesand, if the 4.75 mm No. 4 materials exceed 2 % of the totalweight of aggregate, a minimum sand
20、equivalent value of 50when tested in accordance with Test Method D2419 is re-quired. At least 90 percent by weight of the coarse aggregateshall consist of crushed particles with at least two fracturedfaces as determined by Test Method D5821.4.1.4 Aggregate GradationAggregate size is often repre-sent
21、ed by one of the following gradations and determined inaccordance with Test Methods C136 and C117. Other similargradations may be used, as appropriate.Sieve Size Percent Passing Percent Passing19.5mm34 in. 100 10012.5mm12 in. 95100 951009.50 mm 38 in. 020 70854.75 mm No. 4 05 0152.36 mm No. 8 02 050
22、.075 mm No. 200 01 01NOTE 3The two examples shown in the table above are representativeof typical gradations from current state highway or transportation depart-ments or other user agencies and from industry specifications forasphalt-rubber seal coat. Either gradation may be used for pavements withb
23、lock cracking (see Appendix X1). The first (predominately 12.5 mm 12in.) gradation is recommended for pavements with a high degree of blockcracking. The second (predominately 9.5 mm 38 in.) gradation isrecommended for pavements with a lesser degree of block cracking (seePractice D6433, Figure X1.7 t
24、hrough X1.9).4.1.5 Selection of Coarse AggregateCoarse aggregateshall have abrasion values of less than 30 percent in accordancewith Test Method C131. Crushed gravel (if used) must have atleast 90 percent particles with two faces and 95 percentparticles with one face resulting from crushing in accor
25、dancewith Test Method D5821. The percentage of flat and elongatedparticles should not exceed 10 %, with a ratio of 5:1 inmaximum to minimum dimension, respectively, in accordancewith Test Method D4791.4.1.6 DesignUnless project documents indicate otherwise,the seal coat shall be designed in accordan
26、ce with PracticeD5360 in general, modified for asphalt-rubber applications asdescribed in this practice. The asphalt-rubber binder is spray-applied using an application rate specified in Section 5.1.2,followed by the application of aggregate chips using anapplication rate specified in 5.3.4.NOTE 4Fo
27、r more detailed asphalt-rubber seal coat design guidelinessee the Caltrans Maintenance Technical Advisory Guideline (MTAG).3Also shown in Appendix X2 is a suggested FHWA asphalt-rubber surfacetreatment design procedure.4.2 Emulsified Asphalt Slurry SealThe design and con-struction of the slurry seal
28、 shall conform to Practice D3910.5. Construction of Asphalt-Rubber Cape Seal5.1 Application of Asphalt-Rubber Binder:5.1.1 The following construction recommendations are rep-resentative of the state-of-the-art practice and are not aspecification.5.1.2 It is recommended that the asphalt-rubber binder
29、 forthe asphalt rubber seal coat be applied at a rate of 2.03.0L/m20.500.75 gallons/yd2. For pavement classified in faircondition with a Pavement Condition Index (PCI) rating of 35to 55 in accordance with Practice D6433, a lower applicationrate (generally with a finer aggregate gradation) is recom-m
30、ended and should generally range from 2.02.5L/m30.500.65 gallons/yd2. For pavement classified in poorcondition with a PCI rating of 25 to 35 in accordance withPractice D6433, a higher application rate (generally with acoarser aggregate gradation) is recommended, generally in therange of 2.53.0 L/m30
31、.650.75 gallons/yd2.5.1.3 It is recommended that the Asphalt-rubber binder beplaced upon a clean, dry pavement surface. The pavementsurface temperature is generally limited to a minimum of 13C55F and rising when the asphalt rubber binder is applied.The recommended minimum atmospheric temperature sho
32、uldbe 16C 60F and rising.NOTE 5Placement of asphalt-rubber binder below the minimumtemperatures may cool the material to such a degree that the aggregatemay not embed and stick. This may lead to the premature loss of aggregateand bleeding or flushing of the surface.5.1.4 Distributor bar height, dist
33、ribution speed and shieldingmaterials can be utilized to reduce the effects of wind on thespray distribution. Typically distributor bar height varies be-tween 200 and 350 mm 814 in.NOTE 6When high gusting winds or dusty conditions (or both)prevent or adversely affect binder or aggregate spreading ap
34、plicationoperations, the work should be suspended and rescheduled.5.1.5 All necessary equipment should be in position andready to commence placement operations before starting thework.5.1.6 The asphalt rubber binder is applied to the pavementsurface after mixing and reacting, consistent with the req
35、uire-ments of Specification D6114. The binder should be applied ata material temperature not less than 195C 385F or morethan 215C 415F.5.1.7 Following the asphalt-rubber binder application, thebinder should be promptly covered with the pre-coated aggre-gate.NOTE 7Experience has shown that if more th
36、an 2 minutes elapsebefore the covering of the asphalt-rubber binder, the cover aggregate maynot properly embed into the binder. This could lead to premature raveling3Caltrans, Maintenance Technical Advisory Guide (MTAG), State of CaliforniaDepartment of Transportation, Office of Pavement Preservatio
37、n, Division ofMaintenance, Sacramento, California, October, 2003.D7564/D7564M 09 (2015)2or unsuitable bleeding or flushing (or both) of the pavement surface.Pre-coated aggregate as described in 5.3.1 is preferred in order to ensurea good bond to the asphalt-rubber binder and avoid aggregate chip los
38、s.5.2 Workmanship, Finish and Appearance:5.2.1 When joining edges against areas with aggregate, thejoints should be swept clean of excess aggregate prior to theadjacent application of asphalt rubber binder. Transverse jointsof this type are constructed by placing roofing paper orequivalent across an
39、d over the end of the previous asphaltrubber seal coat application. Once spraying has progressedbeyond the paper, it should be removed immediately.5.2.2 The longitudinal joint between adjacent applicationsof aggregate should coincide with the line between designatedtraffic lanes. Longitudinal joints
40、 are overlapped for completecoverage.NOTE 8Overlapping of longitudinal joints is recommended to ensurecomplete aggregate coverage. Lack of overlapping may result in exposedasphalt-rubber binder without aggregate, which may cause excessivetracking of the asphalt-rubber binder. Generally, overlapping
41、is between100 mm and 200 mm 48 in.5.2.3 At longitudinal joints with aggregate, the edges shouldbe broomed back and blended to minimize differences inelevation, in order to provide a uniform appearance consistentwith the adjacent sealed surface. Care should be taken tominimize ridges and depressions
42、in order to enhance unifor-mity of appearance.5.2.4 The application of asphalt rubber binder to areas notaccessible with the distributor bar on the distributor truck isgenerally accomplished by using pressurized hand wands or byother appropriate means.5.3 Spreading Pre-coated Aggregate:5.3.1 Followi
43、ng the application of the asphalt rubber binder,the pre-coated aggregate is placed over areas receiving asphaltrubber binder. The aggregate should be pre-coated using0.51.0 % asphalt cement by weight of aggregate, conformingto Specifications D946, D3381,orD6373.5.3.2 Aggregate for the asphalt rubber
44、 seal coat should bepre-coated at the hot plant at a temperature between 135C and165C 275325F and then applied at a temperature not lessthan 105C (225F) after applying the asphalt rubber binder.5.3.3 No vehicle, including construction equipment, shouldbe driven over the asphalt rubber binder prior t
45、o the applicationof the pre-coated aggregate.5.3.4 The precoated aggregate is generally applied at a rateof 10.516.0 kg/m22334 lbs/yd2 depending on the pave-ment condition. For pavement in fair condition with a PCIrating of 40 to 55 in accordance with Practice D6433, the finer9.5 mm 38 in. aggregate
46、 gradation (or a similar gradation) isrecommended, with a spread rate of 10.513.5 kg/m22330lbs yd2. For pavement in poor condition with a PCI rating of25 to 40 in accordance with Practice D6433, the coarser 12.5mm 12 in. aggregate gradation (or a similar gradation) isrecommended with an spread rate
47、of 12.016.0 kg/m22734lbs/yd2.NOTE 9Although an asphalt-rubber cape seal has been used onpavements in poor condition, the designer should consider many factorsbefore such a surface treatment is employed on such a pavement. Inparticular, the poor pavement condition should be related to pavementaging a
48、nd weathering, not traffic loads and fatigue cracking. All underly-ing subgrade or base failures (or both) should be corrected and anydrainage problems should be rectified.5.3.5 The spread rate is generally limited to any valuewithin 610 percent of the selected application rate duringspreading to pr
49、ovide a uniform appearance.NOTE 10The term “uniform appearance” refers to a surface that isgenerally free of gaps, ridges, depressions, or other irregularities causedby the application of the asphalt rubber seal coat.5.4 Finishing of the Asphalt-Rubber Seal Coat:5.4.1 The first pass of the rollers over the new asphalt rubberseal coat consists of a minimum of one complete coverage(covering the entire width of the seal, moving forward), usingthe necessary number of pne
