1、Designation: D 6948 03Standard Practice forApplication of Refined Coal Tar (Ready to Use, CommercialGrade)1This standard is issued under the fixed designation D 6948; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 requirements of SpecificationD 69
3、45 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 and II, see 3.3 for standarddefinition of terms.1.2 This standard does not purport to addre
4、ss 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.2. Referenced Documents2.1 ASTM Standards:D 490 Specificat
5、ion for Road Tar2D 5727 Specification for Emulsified Refined Coal Tar (Min-eral Colloid Type)3D 6945 Specification for Emulsified Refined Coal-Tar(Ready to Use, Commercial Grade)33. Terminology3.1 Two types of mixtures are defined in SpecificationD 6945. The ingredients for both types of mixtures ar
6、e nor-mally combined at the contractors yard or at the job site.Refined coal tar emulsion meeting Specification D 5727 isconcentrated when shipped from the manufacturer to theapplicator.3.1.1 Specification D 6945 Type I materialis SpecificationD 5727 material diluted with water typically by the appl
7、icatorafter which aggregate is added.3.1.2 Specification D 6945 Type II materialis Specifica-tion D 5727 material diluted with water typically by theapplicator after which additive and aggregate is added.3.2 The mixtures described in 3.1.1 and 3.1.2 can besubmitted to a laboratory approved by the ow
8、ner for testing oftheir conformance to Specification D 6945 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 tar emulsion, water, or sand (orcombination thereof) mixture to improve the coatings dur
9、a-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 viscosity to improve aggregate suspension.Because there is such a wide variance of additives on t
10、hemarket, 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 mixed materials ap-plied per area of pavement surface, usually expressed in litersper squ
11、are 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 bituminous concrete pavements, newpavements thathave been placed less than 90 days.3.3.5 b
12、ituminous concrete pavements, agedpavementsthat weathered over 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
13、pavement sealer.3.3.7 crack fillera material that is placed in 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
14、-12 in.) wide) in pavements against theentrance or passage of water 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.1This practice is under the jurisdiction of ASTM Co
15、mmittee D08 on Roofing andWaterproofing and is the direct responsibility of Subcommittee D08.09 on Bitumi-nous Emulsions.Current edition approved July 10, 2003. Published August 2003.2Annual Book of ASTM Standards, Vol 04.03.3Annual Book of ASTM Standards, Vol 04.04.1Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 coating reaching itsultimate strength. The duration of
17、 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 process of evaporationof water of the applied seal
18、 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 primingapplication of an initial coat of a materialdesigned to assi
19、st 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 D 490, grade RT-12.3.3.16 refined coal tar emulsio
20、na 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 equipped with amixing tank and positive displacement
21、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-neously mix and apply protective coatings uniform
22、ly 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 coated surfacea surface that has an evendistributio
23、n 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-nation thereof. Its use helps ensure the satisfact
24、ory 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 additive, as specified in SpecificationD 6945.5.2 Crac
25、k 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 application equipment that is capable of applyingthe requir
26、ed 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 units with a pumping distribution system usingpositi
27、ve 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 coat tar emulsion to a uniformconsistency.6.3 The
28、 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 accessible to mechanized equipment, orto accommodate ne
29、at 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 bituminous concrete pavementsurfaces which have been soft
30、ened 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 used, completepatching a minimum of 90 days prio
31、r 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 aconcentrated solution of a water based herbicide appro
32、ved 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 spots mayindicate that the pavement or the pavement base requiresextensive repairs.7.1.3 Clean Existing SurfaceClean pavement
33、 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, grease,vegetation, oil, or any type of objectionable surface f
34、ilm.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 primer.7.1.5 Surface PrimingOlder highly oxidized pavementssometime
35、s have trouble allowing pavement sealers to adhere.To ensure adhesion to sound but oxidized pavements, mix andD6948032apply a prime coat of a type and at a rate recommended by thecoal tar emulsion manufacturer, after all loose aggregate isremoved.7.2 Preparation of New Bituminous Concrete PavementSu
36、rfaces: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 bituminousconcrete surface course and the application of the seal coa
37、t.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 oilrings.) If bituminous surface does not pass this test, add
38、itionaltime 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 MixtureBlend the seal coating mix-ture in the equipment descr
39、ibed in 6.2 using the ingredientsdescribed in the composition table of Specification D 6945Type I or Type II prior to application. The mixing shall producea smooth homogeneous mixture of uniform consistency. (Con-sult the refined coal tar emulsion manufacturer for theirrecommended order of addition
40、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 all times prior to and duringapplication so that a con
41、sistent 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 the mixture at rates speci-fied in Table 1. Applicati
42、on 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/m2(0.60 gal/yd2).8.2.2 Application Rate Guide:8.2.2.1 For pavements with a fine texture, spray applicationsare genera
43、lly 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-perature is at least 10C (50F) and the air temperatur
44、e is 10C(50F) 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 not be applied to hot surfaces underthe summer
45、 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 Wat
46、er 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 CoatsAllow each coatto dry and initially cure befo
47、re 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 su
48、rface.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-tially cure enough to drive over without damage to the sealcoat.9.2 If marginal weather conditions exist during this 8-hdrying time, additional time
49、 will be required. In some cases,this could exceed 24 h. Check the surface after this fortrafficability before opening it to vehicle traffic.10. Striping10.1 If striping is required use a compatible striping paintrecommended by the coal tar emulsion manufacturer.11. Keywords11.1 bituminous concrete pavement sealer; pavement sealer;refined coal tar emulsion; seal coatingTABLE 1 Application Rate ChartApplicationA,B,CFormula Rate of Application Range of Mix,L/m2(gal/yd2)Aggregate GradationCoarse Medium FineFirst and Second Coat,
