沥青混合料课件.pptx

《沥青混合料课件.pptx》由会员分享，可在线阅读，更多相关《沥青混合料课件.pptx（29页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、HMA Volumetric TermsBulk specific gravity(BSG)of compacted HMAMaximum specific gravityAir voidsEffective specific gravity of aggregateVoids in mineral aggregate,VMAVoids filled with asphalt,VFA第1页/共29页Effective volume=volume of solid aggregate particle+volume of surface voids not filled with asphalt

2、Absorbed asphaltVol.of water-perm.voids not filled with asphaltSurface VoidsSolid Agg.Particle第2页/共29页Volumetric RelationshipsVmbVsbVbaVbVseVmmVaVMA第3页/共29页BSG of Compacted HMAAC mixed with agg.and compacted into sampleMass agg.and ACVol.agg.,AC,air voidsGmb=第4页/共29页TestingMixing of asphalt and aggr

3、egateCompaction of sampleMass of dry sampleMass under waterMass saturated surface dry(SSD)第5页/共29页TestingObtain mass of dry compacted sample第6页/共29页TestingObtain mass of specimen at SSD第7页/共29页CalculationsGmb =A/(B-C)Where:A=mass of dry sampleB=mass of SSD sampleC=mass of sample under water第8页/共29页M

4、aximum Specific GravitylLoose(uncompacted)mixtureMass agg.and ACVol.agg.and ACGmm=第9页/共29页TestingMixing of asphalt and aggregateMass in airMass under water第10页/共29页TestingLoose Mix at Room Temperature第11页/共29页TestingVacuum PumpResidual ManometerMetal Bowl with LidShaker Table第12页/共29页CalculationsGmm

5、 =A/(A-C)Where:A=mass of dry sampleC=mass of sample under water第13页/共29页Percent Air VoidslCalculated using both specific gravitiesGmbGmmAir voids=(1 -)100 Mass agg+ACVol.agg,AC,Air VoidsMass agg+ACVol.agg,AC=Vol.agg,ACVol.agg,AC,Air Voids第14页/共29页Example CalculationsAir voids:Gmb=2.222Gmm=2.423第15页/

6、共29页Example CalculationsAir voids:Gmb=2.222Gmm=2.423(1-2.222/2.423)100=8.3%第16页/共29页Effective volume=volume of solid aggregate particle+volume of surface voids not filled with asphaltGse =Mass,dryEffective Specific GravityEffective VolumeAbsorbed asphaltVol.of water-perm.voids not filled with asphal

7、tSurface VoidsSolid Agg.Particle第17页/共29页Effective Specific GravityGse is an aggregate propertyGse=100-Pb100 -PbGmm Gb第18页/共29页Example CalculationsMixed with 5%asphalt cementGmm=2.535Gb =1.03第19页/共29页Example CalculationsMixed with 5%asphalt cementGmm=2.535Gb =1.03 100-5100 -52.535 1.03Gse =2.770第20页

8、/共29页Voids in Mineral AggregateVMA is an indication of film thickness on the surface of the aggregateVMA=100-Gmb Ps Gsb 第21页/共29页Example CalculationsGiven that Gmb=2.455,Ps=95%,and Gsb=2.703第22页/共29页Example CalculationsVMA =100 -(2.455)(95)2.703=13.7第23页/共29页Voids Filled with AsphaltVFA is the perce

9、nt of VMA that is filled with asphalt cementVFA=100 xVMA-Va VMA 第24页/共29页Percent Binder AbsorbedPba is the percent of absorbed asphalt by mass of aggregatePba=100(Gse-Gsb Gsb Gse)Gb第25页/共29页Effective volume=volume of solid aggregate particle+volume of surface voids not filled with asphaltGse =Mass,d

10、ryEffective Specific GravityEffective VolumeAbsorbed asphaltVol.of water-perm.voids not filled with asphaltSurface VoidsSolid Agg.Particle第26页/共29页Effective Asphalt ContentThe effective asphalt content is the total asphalt content minus the percent lost to absorption(based on mass of total mix).Pbe=Pb-Pba100Ps第27页/共29页Questions-?第28页/共29页感谢您的观看。第29页/共29页