1、Designation: D6948/D6948M 03 (Reapproved 2011)1Standard 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 cas
2、e 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.1NOTEUnits information was editorially revised in June 2011.1. Scope1.1 This practice covers the applic
3、ation of emulsified re-fined coal tar slurry meeting the requirements of SpecificationD6945 Types I and II, by mechanized equipment as a weatherprotection and petroleum (aliphatic) solvent resistant sealer foruse on bituminous concrete pavements. In order to clarify thedifferences between Types I an
4、d II, see 3.3 for standarddefinition of terms.1.2 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, eachsystem shall be used independently of the other. Combiningvalues from the
5、two systems may result in non-conformancewith the standard.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-bi
6、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D490 Specification for Road TarD5727 Specification for Emulsified Refined Coal Tar (Min-eral Colloid Type)D6945 Specification for Emulsified Refined Coal-Tar(Ready to Use, Commercial Grade)3. Terminology3.1 Two ty
7、pes of mixtures are defined in SpecificationD6945. The ingredients for both types of mixtures are normallycombined at the contractors yard or at the job site. Refinedcoal tar emulsion meeting Specification D5727 is concentratedwhen shipped from the manufacturer to the applicator.3.1.1 Specification
8、D6945 Type I materialis SpecificationD5727 material diluted with water typically by the applicatorafter which aggregate is added.3.1.2 Specification D6945 Type II materialis Specifica-tion D5727 material diluted with water typically by theapplicator after which additive and aggregate is added.3.2 Th
9、e 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 Type I or Type IIprior to their actual use on the job.3.3 Definitions:3.3.1 additiveone or more ingredients that can be addedto a specific refined coal
10、 tar emulsion, water, or sand (orcombination thereof) mixture to improve the coatings dura-bility, fuel resistance, drying time, color uniformity, or lengthof time required before opening the surface to traffic, orcombination thereof. This material can also be used to modifythe wet mixtures viscosit
11、y to improve aggregate suspension.Because there is such a wide variance of additives on themarket, the aforementioned results may not take place. If anadditive is used, it is recommended that it be supplied by thesame manufacturer as the refined coal tar emulsion.3.3.2 application ratethe volume of
12、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 seal coat or sealer.3.3.4 bi
13、tuminous 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 approved May 1, 2011. Published
14、June 2011. Originallyapproved in 2003. Last previous edition approved in 2003 as D2948 03. DOI:10.1520/D6948_D6948M-03R11E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.3.5 bituminous concrete pavements, agedpavementsthat weathered over at least one summer season and haveshown signs of o
16、ne 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 in a pavementcrack or joint to fill but not necessaril
17、y 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 water or other debris.3.3.9 crude coal tarcondensed ma
18、terial 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 coating mixtureover the period of days resulting in the coa
19、ting 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 to the seal coat.3.3.12 drying (of the seal coat)the
20、 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 eitherwith a spray or squeegee unit.3.3.14 primingapplicati
21、on 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 distilled coal tarmeeting the requirements of Specification
22、 D490, grade RT-12.3.3.16 refined coal tar emulsiona stable and homoge-neous dispersion of refined coal tar, clay, mineral fillers, andspecialty chemicals in water.3.3.17 seal coatingprocess of applying a protective coat-ing to a bituminous concrete pavement.3.3.18 spray unita piece of equipment equ
23、ipped 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 witha mixing tank and squeegeeing mechanism that can homoge
24、-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 sealcoat, except for wear from traffic.3.3.21 uniform c
25、oated 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, property owners or their representatives, or combi-
26、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 coal tar emulsion water andsand, with or without an addi
27、tive, as specified in SpecificationD6945.5.2 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 coal taremulsion manufacturer.6. Equipment6.1 Use applicatio
28、n 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-type application device. To ensure this,equip all spray uni
29、ts 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 tanks shall be capable of mixing orcirculating, or both, the
30、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 or brush application will berestricted to places not access
31、ible 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 Pavement Surfaces (see3.3.5).7.1.1 PatchingPatch all bitumino
32、us 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 existing pavement. If asolvent containing cold-applied material is
33、 used, completepatching a minimum of 90 days prior to the planned applicationof the sealer to permit solvent escape before sealing.7.1.2 Crack SealingRemove all vegetation and debrisfrom cracks to a minimum depth of 13.0 mm 12 in. Ifextensive vegetation exists, treat the specific area with aconcentr
34、ated solution of a water based herbicide approved bythe manufacturer. Fill all cracks ignoring hairline cracks (3D6948/D6948M 03 (2011)12mm 18 in. wide) with a crack sealant. Wider cracks (over 38mm 1-12 in. wide, along with soft or sunken spots mayindicate that the pavement or the pavement base req
35、uiresextensive 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. The cleaningactivity must leave the surface free of dust, dirt
36、, 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 potablewater. After cleaning treat these areas with an oil spot pri
37、mer.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 tar emulsion manufacturer, after all loose aggregate isremov
38、ed.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 orgreater shall elapse between the placement of a bituminousconcr
39、ete 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 wet the surface uniformly without crawling or showing oilring
40、s.) 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 of Seal Coating Mixture8.1 Mixing:8.1.1 Preparation of Mixture
41、Blend the seal coating mix-ture in the equipment described in 6.2 using the ingredientsdescribed in the composition table of Specification D6945Type I or Type II prior to application. The mixing shall producea smooth homogeneous mixture of uniform consistency. (Con-sult the refined coal tar emulsion
42、 manufacturer for theirrecommended order of addition of the ingredients.) During theentire mixing and application process, no breaking, segregat-ing, or hardening of the emulsion, nor balling or lumping of thesand will be permitted. Continue to agitate the seal coatingmixture in the mixing tank at a
43、ll times prior to and duringapplication so that a consistent mix is applied.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.8.2 Application of Seal Coating Mixture:8.2.1 Application RateApply
44、the mixture at rates speci-fied in Table 1. Application rates depend on surface character-istics and application method (spray or squeegee). Rates arenot to exceed the values given in Table 1 and at no time willtotal coats exceed 2.7 L/m20.60 gal/yd2.8.2.2 Application Rate Guide:8.2.2.1 For pavement
45、s 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 Precautions:8.2.3.1 Sealer should not be applied unless pavement tem-pe
46、rature 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 anticipated within 8 h afterapplication is completed.8.2.3.3 Sealer should
47、 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
48、 the temperature dropsbelow 4C 40F.8.2.4 Water FogTo provide maximum adhesion, themanufacturer may require a water fog spray (dampening).8.2.5 Prime CoatWhen needed see 7.1.5.8.2.6 First CoatApply the mixture uniformly to obtainthe rates specified in Table 1.8.2.7 Dry and Initial Cure Between CoatsA
49、llow each coatto dry and initially cure before applying all subsequent coats.8.2.8 Second CoatApply the second coat as outlined forthe first coat above.8.2.9 Additional CoatsAdditional coats may be appliedover the entire surface or in heavy traffic areas such as drivelanes.8.2.10 Final LookThe finished surface shall present auniform coated surface.9. Drying and Initial Cure9.1 Allow the final coat to dry a minimum of 8 h under gooddaylight drying conditions before opening to traffic and ini-tia
