1、Designation: D6948/D6948M 03 (Reapproved 2017)Standard Practice forApplication of Refined Coal Tar (Ready to Use, CommercialGrade)1This standard is issued under the fixed designation D6948/D6948M; the number immediately following the designation indicates theyear of original adoption or, in the case
2、 of revision, 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. Scope1.1 This practice covers the application of emulsified re-fined coal tar slurry meeting the requ
3、irements of SpecificationD6945/D6945M Types I and II, by mechanized equipment as aweather protection and petroleum (aliphatic) solvent resistantsealer for use on bituminous concrete pavements. In order toclarify the differences between Types I and II, see 3.3 forstandard definition of terms.1.2 The
4、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, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the stan
5、dard.1.3 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 This i
6、nternational standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TB
7、T) Committee.2. Referenced Documents2.1 ASTM Standards:2D490 Specification for Road TarD5727/D5727M Specification for Emulsified Refined CoalTar (Mineral Colloid Type)D6945/D6945M Specification for Emulsified Refined Coal-Tar (Ready to Use, Commercial Grade)3. Terminology3.1 Two types of mixtures ar
8、e defined in SpecificationD6945/D6945M. The ingredients for both types of mixturesare normally combined at the contractors yard or at the jobsite. Refined coal tar emulsion meeting Specification D5727/D5727M is concentrated when shipped from the manufacturerto the applicator.3.1.1 Specification D694
9、5/D6945M Type I materialisSpecification D5727/D5727M material diluted with watertypically by the applicator after which aggregate is added.3.1.2 Specification D6945/D6945M Type II materialisSpecification D5727/D5727M material diluted with watertypically by the applicator after which additive and agg
10、regateis added.3.2 The mixtures described in 3.1.1 and 3.1.2 can besubmitted to a laboratory approved by the owner for testing oftheir conformance to Specification D6945/D6945M TypeIorType II prior to their actual use on the job.3.3 Definitions:3.3.1 additiveone or more ingredients that can be added
11、 toa specific refined coal tar emulsion, water, or sand (or combi-nation thereof) mixture to improve the coatings durability, fuelresistance, drying time, color uniformity, or length of timerequired before opening the surface to traffic, or combinationthereof. This material can also be used to modif
12、y the wetmixtures viscosity to improve aggregate suspension. Becausethere is such a wide variance of additives on the market, theaforementioned results may not take place. If an additive isused, it is recommended that it be supplied by the samemanufacturer as the refined coal tar emulsion.3.3.2 appl
13、ication ratethe volume of mixed materials ap-plied per area of pavement surface, usually expressed in litersper square meter (L/m2) gallons per square yard (gal/yd2).3.3.3 applied mixturethe combination of all ingredientsmixed together and ready for application to the pavement. Alsoreferred to as se
14、al coat or sealer.3.3.4 bituminous concrete pavements, newpavements thathave been placed less than 90 days.1This practice is under the jurisdiction ofASTM Committee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.09 on Bitumi-nous Emulsions.Current edition approv
15、ed May 1, 2017. Published May 2017. Originallyapproved in 2003. Last previous edition approved in 2011 as D6948/D6948M 03(2011)1. DOI: 10.1520/D6948_D6948M-03R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
16、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 StatesThis international standard was developed in accordance with internationally recognize
17、d principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.3.5 bituminous concrete pavements, agedpavementsthat weathered ove
18、r at least one summer season and haveshown signs of one or more of the following: cracking,raveling, aggregate polishing or graying due to oxidation, orcombination thereof.3.3.6 brush applicatora hand type or mechanized brushused to apply pavement sealer.3.3.7 crack fillera material that is placed i
19、n a pavementcrack or joint to fill but not necessarily seal the void created bythe crack or joint.3.3.8 crack sealanta material that has adhesive and cohe-sive properties to seal cracks, joints or other narrow openings(less than 38.5 mm 1-12 in. wide) in pavements against theentrance or passage of w
20、ater or other debris.3.3.9 crude coal tarcondensed material taken from thecoking process (high temperature heating of coal under avacuum) and containing all of the volatile constituents.3.3.10 cure, final (of the seal coat)the process of evapo-ration of water and volatiles of the applied seal coatin
21、g mixtureover the period of days resulting in the coating reaching itsultimate strength. The duration of this process is dependentupon ambient conditions.3.3.11 cure, initial (of the seal coat)the condition of anapplied seal coating material that enables it to withstandvehicle traffic without damage
22、 to the seal coat.3.3.12 drying (of the seal coat)the process of evaporationof water of the applied seal coating mixture resulting in thecoating being able to sustain light foot traffic.3.3.13 mechanized application equipmentequipment usedto mix and apply the refined coal tar emulsion mixture either
23、with a spray or squeegee unit.3.3.14 primingapplication of an initial coat of a materialdesigned to assist the adhesion of the additional coats of sealcoating materials. Primers are always used as under coatingsand are not designed to be used by themselves.3.3.15 refined coal tara selectively distil
24、led coal tar meet-ing the requirements of Specification D490, grade RT-12.3.3.16 refined coal tar emulsiona stable and homogeneousdispersion of refined coal tar, clay, mineral fillers, and specialtychemicals in water.3.3.17 seal coatingprocess of applying a protective coat-ing to a bituminous concre
25、te pavement.3.3.18 spray unita piece of equipment equipped with amixing tank and positive displacement pump that can homo-geneously mix and apply protective coatings uniformly overthe entire width of a spray bar or wand type application device.3.3.19 squeegee unita piece of equipment equipped with a
26、mixing tank and squeegeeing mechanism that can homoge-neously mix and apply protective coatings uniformly over theentire width of a rubber squeegee or brush type applicationdevice.3.3.20 traffcabilitythe ability of an applied seal coatingmaterial to withstand vehicle traffic without damage to the se
27、alcoat, except for wear from traffic.3.3.21 uniform coated surfacea surface that has an evendistribution of seal coating material free of pinholes, streaks, orother uneven characteristics, or combination thereof.4. Significance and Use4.1 This practice is designed as a guide for architects,engineers
28、, property owners or their representatives, or combi-nation thereof. Its use helps ensure the satisfactory perfor-mance of the protective coating system when applied overbituminous concrete pavements.5. Materials5.1 Refined Coal Tar Emulsion (Seal Coating) MixtureAmixture of concentrated refined coa
29、l tar emulsion water andsand, with or without an additive, as specified in SpecificationD6945/D6945M.5.2 Crack SealantAs specified by the refined coal taremulsion manufacturer.5.3 Oil Spot PrimerAs specified by the refined coal taremulsion manufacturer.5.4 Pavement PrimerAs specified by the refined
30、coal taremulsion manufacturer.6. Equipment6.1 Use application equipment that is capable of applyingthe required coating rates evenly over the entire width of theapplication mechanism to provide a continuously coated sur-face. For spray units, this can be accomplished with either aspray bar or a wand
31、-type application device. To ensure this,equip all spray units with a pumping distribution system usingpositive displacement pumps. All squeegee/brush units shall beproperly adjusted and in condition for application of seal coatmaterials so that there are no streaks in the coating.6.2 Bulk storage t
32、anks shall be capable of mixing orcirculating, or both, the coat tar emulsion to a uniformconsistency.6.3 The mixing part of the application equipment must betank type with a mechanically powered, full sweep mixercapable of homogeneously mixing the entire contents of thetank.6.4 Use of hand squeegee
33、 or brush application will berestricted to places not accessible to mechanized equipment, orto accommodate neat trim work at curbs and so forth. Materialthat is applied by hand application shall meet the samestandards as that applied by machine.7. Surface Preparation7.1 Preparation of Aged Asphalt P
34、avement Surfaces (see3.3.5).7.1.1 PatchingPatch all bituminous concrete pavementsurfaces which have been softened by petroleum derivates orhave failed due to any other cause. Remove the damagedpavement to the full depth of the damage and replace with newasphalt concrete similar to that of the existi
35、ng pavement. If asolvent containing cold-applied material is used, completepatching a minimum of 90 days prior to the planned applicationof the sealer to permit solvent escape before sealing.D6948/D6948M 03 (2017)27.1.2 Crack SealingRemove all vegetation and debrisfrom cracks to a minimum depth of 1
36、3.0 mm 12 in. Ifextensive vegetation exists, treat the specific area with aconcentrated solution of a water based herbicide approved bythe manufacturer. Fill all cracks ignoring hairline cracks (3mm 18 in. wide) with a crack sealant. Wider cracks (over 38mm 1-12 in. wide), along with soft or sunken
37、spots mayindicate that the pavement or the pavement base requiresextensive repairs.7.1.3 Clean Existing SurfaceClean pavement surface im-mediately prior to placing the prime coat or seal coat by airblowing, sweeping, or flushing well with water (leaving nostanding water) or a combination of these. T
38、he cleaningactivity must leave the surface free of dust, dirt, grease,vegetation, oil, or any type of objectionable surface film.7.1.4 Oil Spot PrimingRemove oil or grease that has notpenetrated the asphalt pavement by scraping or by scrubbingwith a detergent, then rinse thoroughly with clean potabl
39、ewater. After cleaning treat these areas with an oil spot primer.7.1.5 Surface PrimingOlder highly oxidized pavementssometimes have trouble allowing pavement sealers to adhere.To ensure adhesion to sound but oxidized pavements, mix andapply a prime coat of a type and at a rate recommended by thecoal
40、 tar emulsion manufacturer, after all loose aggregate isremoved.7.2 Preparation of New Bituminous Concrete PavementSurfaces:7.2.1 Allow new bituminous concrete surfaces to cure sothat there is no accumulation of oils on the surface. A period ofat least 90 days at daytime temperatures of 21C 70F orgr
41、eater shall elapse between the placement of a bituminousconcrete surface course and the application of the seal coat.7.2.2 Perform a water-break-free test to confirm that thesurface oils have degraded and dissipated. (Cast one gallon ofclean water out over the surface. The water should sheet outand
42、wet the surface uniformly without crawling or showing oilrings.) If bituminous surface does not pass this test, additionaltime must be allowed and retesting should be done prior tosealing.7.2.3 CleaningClean as detailed in 7.1.3.7.2.4 Oil Spot PrimingWhen needed see 7.1.4.8. Mixing and Application o
43、f Seal Coating Mixture8.1 Mixing:8.1.1 Preparation of MixtureBlend the seal coating mix-ture in the equipment described in 6.2 using the ingredientsdescribed in the composition table of Specification D6945/D6945M Type I or Type II prior to application. The mixingshall produce a smooth homogeneous mi
44、xture of uniformconsistency. (Consult the refined coal tar emulsion manufac-turer for their recommended order of addition of the ingredi-ents.) During the entire mixing and application process, nobreaking, segregating, or hardening of the emulsion, norballing or lumping of the sand will be permitted
45、. Continue toagitate the seal coating mixture in the mixing tank at all timesprior to and during application so that a consistent mix isapplied.8.1.2 Small additional increments of water may be neededto provide a workable consistency but in no case shall the watercontent exceed the specified amount.
46、8.2 Application of Seal Coating Mixture:8.2.1 Application RateApply the mixture at rates specifiedin Table 1. Application rates depend on surface characteristicsand application method (spray or squeegee). Rates are not toexceed the values given in Table 1 and at no time will totalcoats exceed 2.7 L/
47、m20.60 gal/yd2.8.2.2 Application Rate Guide:8.2.2.1 For pavements with a fine texture, spray applicationsare generally recommended.8.2.2.2 For pavements with a rough texture or old oxidizedpavements one squeegee coat is generally recommended, thenanother squeegee coat or one spray coat.8.2.3 Precaut
48、ions:8.2.3.1 Sealer should not be applied unless pavement tem-perature is at least 10C 50F and the air temperature is 10C50F and rising.8.2.3.2 Sealer should not be applied during rainy or wetweather, during heavy fog, dew, and during hours of operationof sprinkler systems or when rain is anticipate
49、d within 8 h afterapplication is completed.8.2.3.3 Sealer should not be applied to hot surfaces underthe summer sun (over 32C 90F) without first applyingpavement primer or first cooling the surface with clean water.Water should dampen the surface without leaving puddles.8.2.3.4 Since an emulsion may be damaged by freezing, itshould be protected at all times when the temperature dropsbelow 4C 40F.8.2.4 Water FogTo provide maximum adhesion, themanufacturer may require a water fog spray (dampening).8.2.5 Pri
