沥青抽提试验和马歇尔稳定性试验.doc

Determining Bitumen ContentPosted in Civil Engineering Tests |  Email This Post |BITUMEN CONTENTThis test is done to determine the bitumen content as per ASTM 2172. The apparatus needed to determine bitumen content are -i) Centrifuge extractorii) Miscellaneous bowl, filter paper, balance and commercial benzene.A sample of 500g is taken.Procedure to determine bitumen contenti) If the mixture is not soft enough to separate with a trowel,place 1000g of it in a large pan and warm upto 100oC to separate the particles of the mixture uniformly.ii) Place the sample (Weight A) in the centrifuge extractor. Cover the sample with benzene, put the filter paper on it with the cover plate tightly fitted on the bowl.iii) Start the centrifuge extractor, revolving slowly and gradually increase the speed until the solvent ceases to flow from the outlet.iv) Allow the centrifuge extractor to stop. Add 200ml benzene and repeat the procedure.v) Repeat the procedure at least thrice, so that the extract is clear and not darker than the light straw colour and record the volume of total extract in the graduated vessel.vi) Remove the filter paper from the bowl and dry in the oven at 110 + 5oC. After 24hours, take the weight of the extracted sample (Weight B).REPORTING OF RESULTSBitumen content = (A-B)/B×100 %Repeat the test thrice and average the results.Determining The Marshall Stability of Bituminous MixturePosted in Civil Engineering Tests |  Email This Post |This test is done to determine the Marshall stability of bituminous mixture as per ASTM D 1559. The principle of this test is that Marshall stability is the resistance to plastic flow of cylindrical specimens of a bituminous mixture loaded on the lateral surface. It is the load carrying capacity of the mix at 60oC and is measured in kg. The apparatus needed to determine Marshall stability of bituminous mixture isi) Marshall stability apparatusii) Balance and water bathThe sample needed isFrom Marshall stability graph, select proportions of coarse aggregates, fine aggregates and filler in such a way, so as to fulfill the required specification. The total weight of the mix should be 1200g.Procedure to determine Marshall stability of bituminous mixture i) Heat the weighed aggregates and the bitumen separately upto 170oC and 163oC respectively.ii) Mix them thoroughly, transfer the mixed material to the compaction mould arranged on the compaction pedestal.iii) Give 75 blows on the top side of the specimen mix with a standard hammer (45cm, 4.86kg). Reverse the specimen and give 75 blows again. Take the mould with the specimen and cool it for a few minutes.iv) Remove the specimen from the mould by gentle pushing. Mark the specimen and cure it at room temperature, overnight.v) A series of specimens are prepared by a similar method with varying quantities of bitumen content, with an increment of 0.5% (3 specimens) or 1 bitumen content.vi) Before testing of the mould, keep the mould in the water bath having a temperature of 60oC for half an hour.vii) Check the stability of the mould on the Marshall stability apparatus.REPORTING OF RESULTSPlot % of bitumen content on the X-axis and stability in kg on the Y-axis to get maximum Marshall stability of the bitumen mix. A sample plot is given