1、Designation: D7564/D7564M 09 (Reapproved 2015)D7564/D7564M 16Standard 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 revi
2、sion, the year 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. Scope Scope*1.1 This practice covers asphalt-rubber cape seal, which is defined as the application of an asph
3、alt-rubber seal coat placed ontoan existing pavement surface, followed by the application of a conventional Type II or III slurry seal.NOTE 1An asphalt-rubber seal coat is also known as a stress absorbing membrane (SAM) which consists of an asphalt-rubber membrane sealfollowed by the application of
4、precoated aggregate chips.1.2 An asphalt-rubber cape seal is commonly used to extend the service life of low to medium trafficked and moderatelydistressed asphalt-surfaced pavements. The existing pavement condition can be used to determine the application rates for theasphalt-rubber binder and aggre
5、gate as well as the aggregate gradation. Pavements in relatively poor condition will require acoarser aggregate with a higher binder application rate.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exa
6、ct equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof
7、the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations 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 F
8、iner than 75-m (No. 200) Sieve in Mineral Aggregates by WashingC127 Test Method for Relative Density (Specific Gravity) and Absorption of Coarse AggregateC128 Test Method for Relative Density (Specific Gravity) and Absorption of Fine AggregateC131 Test Method for Resistance to Degradation of Small-S
9、ize Coarse Aggregate by Abrasion and Impact in the Los AngelesMachineC136 Test Method for Sieve Analysis of Fine and Coarse AggregatesD946 Specification for Penetration-Graded Asphalt Cement for Use in Pavement ConstructionD1139 Specification for Aggregate for Single or Multiple Bituminous Surface T
10、reatmentsD2196 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational ViscometerD2419 Test Method for Sand Equivalent Value of Soils and Fine AggregateD3381 Specification for Viscosity-Graded Asphalt Cement for Use in Pavement ConstructionD3910 Practices for Design, Testing
11、, and Construction of Slurry SealD4791 Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse AggregateD5360 Practice for Design and Construction of Bituminous Surface TreatmentsD5821 Test Method for Determining the Percentage of Fractured Particles in Coarse
12、AggregateD6114 Specification for Asphalt-Rubber BinderD6373 Specification for Performance Graded Asphalt BinderD6433 Practice for Roads and Parking Lots Pavement Condition Index Surveys1 This practice is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct resp
13、onsibility of Subcommittee D04.24 on AsphaltSurface Treatments.Current edition approved Jan. 1, 2015May 1, 2016. Published February 2015May 2016. Originally approved in 2009. Last previous edition approved in 20092015 asD7564/D7564M 09.D7564/D7564M 09 (2015). DOI: 10.1520/D7564_D7564M-09R15.10.1520/
14、D7564_D7564M-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is
15、intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the c
16、urrent versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Significance and Use3.1 T
17、he procedure described in this practice is used to design and construct an asphalt-rubber cape seal that will provide awearing course when subjected to low to medium traffic volumes and where the pavement distress is due to block-type crackingresulting from pavement aging or reflective cracking only
18、 (not where there are clear indications of fatigue cracking due to repeatedheavy axle loads).NOTE 2Block cracking is defined in Practice D6433. See Appendix X1 for an example of block cracking due to aging.4. Materials4.1 Asphalt-Rubber Seal Coat (or Stress Absorbing MembraneSAM):4.1.1 Asphalt Cemen
19、tThe asphalt cement for the asphalt-rubber seal coat should comply with the requirements ofSpecifications D946, D3381, or D6373. Asphalt cement grade selection is based on considerations of local climatic and trafficconditions. The asphalt-rubber supplier should perform routine Q/C laboratory testin
20、g to ensure compatibility of the selectedasphalt cement with the requirements of Specification D6114.4.1.2 Asphalt-RubberThe asphalt-rubber binder consists of an interacted blend of paving grade asphalt cement, groundrecycled tire rubber, and other additives as needed to conform to the requirements
21、of Specification D6114.4.1.3 AggregateAggregate consists of crushed materials conforming to the physical requirements of Specification D1139 fordegradation, soundness, and deleterious substances and, if the 4.75 mm No. 4 materials exceed 2 % of the total weight ofaggregate, a minimum sand equivalent
22、 value of 50 when tested in accordance with Test Method D2419 is required. At least 90percent by weight of the coarse aggregate shall consist of crushed particles with at least two fractured faces as determined by TestMethod D5821.4.1.4 Aggregate GradationAggregate size is often represented by one o
23、f the following gradations and determined inaccordance with Test Methods C136 and C117. Other similar gradations may be used, as appropriate.Sieve Size Percent Passing Percent Passing19.5 mm 34 in. 100 10012.5 mm 12 in. 95100 951009.50 mm 38 in. 020 70854.75 mm No. 4 05 0152.36 mm No. 8 02 050.075 m
24、m No. 200 01 01NOTE 3The two examples shown in the table above are representative of typical gradations from current state highway or transportation departmentsor other user agencies and from industry specifications for asphalt-rubber seal coat. Either gradation may be used for pavements with block
25、cracking (seeAppendix X1). The first (predominately 12.5 mm 12 in.) gradation is recommended for pavements with a high degree of block cracking. The second(predominately 9.5 mm 38 in.) gradation is recommended for pavements with a lesser degree of block cracking (see Practice D6433, Figure X1.7 thro
26、ughX1.9).4.1.5 Selection of Coarse AggregateCoarse aggregate shall have abrasion values of less than 30 percent% in accordance withTest Method C131. Crushed gravel (if used) must have at least 90 percent particles with two faces and 95 percent particles withone face resulting from crushing in accord
27、ance with Test Method D5821. The percentage of flat and elongated particles should notexceed 10 %, with a ratio of 5:1 in maximum to minimum dimension, respectively, in accordance with Test Method D4791.4.1.6 DesignUnless project documents indicate otherwise, the seal coat shall be designed in accor
28、dance with Practice D5360in general, modified for asphalt-rubber applications as described in this practice. The asphalt-rubber binder is spray-applied usingan application rate specified in Section 5.1.2, followed by the application of aggregate chips using an application rate specified in5.3.4.NOTE
29、 4For more detailed asphalt-rubber seal coat design guidelines see the Caltrans Maintenance Technical Advisory Guideline (MTAG).3 Alsoshown in Appendix X2 is a suggested FHWA asphalt-rubber surface treatment design procedure.4.2 Emulsified Asphalt Slurry SealThe design and construction of the slurry
30、 seal 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 representative of the state-of-the-art practice and are not a specification.5.1.2 It is recommended that the asphalt-rubber b
31、inder for the asphalt rubber seal coat be applied at a rate of 2.03.0 2.0 to 3.0L/m2 0.500.75 0.50 to 0.75 gallons/yd2. For pavement classified in fair condition with a Pavement Condition Index (PCI)rating of 35 to 55 in accordance with Practice D6433, a lower application rate (generally with a fine
32、r aggregate gradation) isrecommended and should generally range from 2.02.5 2.0 to 2.5 L/m3 0.500.65 0.50 to 0.65 gallons/yd2. For pavementclassified in poor condition with a PCI rating of 25 to 35 in accordance with Practice D6433, a higher application rate (generallywith a coarser aggregate gradat
33、ion) is recommended, generally in the range of 2.53.0 2.5 to 3.0 L/m3 0.650.75 0.65 to 0.75gallons/yd2.3 Caltrans, Maintenance TechnicalAdvisory Guide (MTAG), State of California Department of Transportation, Office of Pavement Preservation, Division of Maintenance,Sacramento, California, October, 2
34、003.D7564/D7564M 1625.1.3 It is recommended that the Asphalt-rubber binder be placed upon a clean, dry pavement surface. The pavement surfacetemperature is generally limited to a minimum of 13C 55F and rising when the asphalt rubber binder is applied. Therecommended minimum atmospheric temperature s
35、hould be 16C 60F and rising.NOTE 5Placement of asphalt-rubber binder below the minimum temperatures may cool the material to such a degree that the aggregate may notembed and stick. This may lead to the premature loss of aggregate and bleeding or flushing of the surface.5.1.4 Distributor bar height,
36、 distribution speed and shielding materials can be utilized to reduce the effects of wind on the spraydistribution. Typically distributor bar height varies between 200 and 350 mm 814 8 to 14 in.NOTE 6When high gusting winds or dusty conditions (or both) prevent or adversely affect binder or aggregat
37、e spreading application operations, thework should be suspended and rescheduled.5.1.5 All necessary equipment should be in position and ready to commence placement operations before starting the work.5.1.6 The asphalt rubber binder is applied to the pavement surface after mixing and reacting, consis
38、tent with the requirementsof Specification D6114. The binder should be applied at a material temperature not less than 195C 385F or more than 215C415F.5.1.7 Following the asphalt-rubber binder application, the binder should be promptly covered with the pre-coated aggregate.NOTE 7Experience has shown
39、 that if more than 2 minutes elapse before the covering of the asphalt-rubber binder, the cover aggregate may notproperly embed into the binder. This could lead to premature raveling or unsuitable bleeding or flushing (or both) of the pavement surface. Pre-coatedaggregate as described in 5.3.1 is pr
40、eferred in order to ensure a good bond to the asphalt-rubber binder and avoid aggregate chip loss.5.2 Workmanship, Finish and Appearance:5.2.1 When joining edges against areas with aggregate, the joints should be swept clean of excess aggregate prior to the adjacentapplication of asphalt rubber bind
41、er. Transverse joints of this type are constructed by placing roofing paper or equivalent acrossand over the end of the previous asphalt rubber seal coat application. Once spraying has progressed beyond the paper, it shouldbe removed immediately.5.2.2 The longitudinal joint between adjacent applicat
42、ions of aggregate should coincide with the line between designated trafficlanes. Longitudinal joints are overlapped for complete coverage.NOTE 8Overlapping of longitudinal joints is recommended to ensure complete aggregate coverage. Lack of overlapping may result in exposedasphalt-rubber binder with
43、out aggregate, which may cause excessive tracking of the asphalt-rubber binder. Generally, overlapping is between 100 mmand 200 mm 48 4 to 8 in.5.2.3 At longitudinal joints with aggregate, the edges should be broomed back and blended to minimize differences in elevation,in order to provide a uniform
44、 appearance consistent with the adjacent sealed surface. Care should be taken to minimize ridges anddepressions in order to enhance uniformity of appearance.5.2.4 The application of asphalt rubber binder to areas not accessible with the distributor bar on the distributor truck is generallyaccomplish
45、ed by using pressurized hand wands or by other appropriate means.5.3 Spreading Pre-coated Aggregate:5.3.1 Following the application of the asphalt rubber binder, the pre-coated aggregate is placed over areas receiving asphaltrubber binder. The aggregate should be pre-coated using 0.51.0 % 0.5 to 1.0
46、 % asphalt cement by weight of aggregate,conforming to Specifications D946, D3381, or D6373.5.3.2 Aggregate for the asphalt rubber seal coat should be pre-coated at the hot plant at a temperature between 135C and 165C275325F 275 to 325F and then applied at a temperature not less than 105C (225F) aft
47、er applying the asphalt rubber binder.5.3.3 No vehicle, including construction equipment, should be driven over the asphalt rubber binder prior to the application ofthe pre-coated aggregate.5.3.4 The precoated aggregate is generally applied at a rate of 10.516.0 10.5 to 16.0 kg/m2 2334 23 to 34 lbs/
48、yd2depending on the pavement condition. For pavement in fair condition with a PCI rating of 40 to 55 in accordance with PracticeD6433, the finer 9.5 mm 38 in. aggregate gradation (or a similar gradation) is recommended, with a spread rate of 10.513.5 10.5to 13.5 kg/m2 2330 lbsyd2. For pavement in po
49、or condition with a PCI rating of 25 to 40 in accordance with Practice D6433,the coarser 12.5 mm 12 in. aggregate gradation (or a similar gradation) is recommended with an spread rate of 12.016.0 12.0to 16.0 kg/m2 2734 27 to 34 lbs/yd2 .NOTE 9Although an asphalt-rubber cape seal has been used on pavements in poor condition, the designer should consider many factors before sucha surface treatment is employed on such a pavement. In particular, the poor pav
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