Research On Composite Modified Asphalt And Performance Of Kinds Of Large Void Modified Asphalt Mixtures

Large void asphalt pavement having good draingage, reducing water in the street, improving the security, absorbing the sound waves, reducing the traffic noise, is one of the most effective ways to reduce urban road traffic noise. Compared with ordinary asphalt pavement, large porous asphalt pavement has higher requirements on properties of raw materials, high and low temperature performance of asphalt mixture, water stability and mechanical properties of asphalt mixture. Common asphalt has been unable to meet the requirements, preparation of modified asphalt is one of the key factors in whether large porous asphalt pavement widely applied.In this paper, 90asphalt is taken as the original asphalt, SBS, rubber powder, SBS and rubber powder composite as the modifier respectively, research on different shear temperature, shear time and content of the modified asphalt penetration degree, softening point and ductility of rules, determines the appropriate shear temperature, shear time and content. Research on different mixing sequence and content of properties of composite modified asphalt, determines the appropriate content of SBS and rubber powder modified asphalt, sequence of first SBS, then rubber power. Compared with TPS modified asphalt, by the original asphalt, SBS, rubber powder, SBS and rubber powder composite penetration, softening point, low temperature ductility, results show that 5% SBS and 11% rubber power composite modified asphalt close to TPS asphalt., better than other modified asphalt.20% as the initial porosity, determining the rate of 12% through 2.36mm sieve, using the flow test to determine the optimum asphalt content, rending the different modified asphalt aggregate ratio mixture of theoretical maximum specific gravity, bulk volume specific gravity, porosity, connectivity porosity diagram. Comparision of the modified asphalt high temperature performance, water stability, compressive properties and splitting properties, the results show that SBS and rubber power modified asphalt mixture composite is better than SBS, rubber power modified asphalt mixture, close to TPS modified asphalt mixture.Basalt, hard texture, wear well, but the price is high and distribution limited. The price of limestone is low, distribution widely. Research on limestone replacement of basalt as coarse aggregate, measures in basalt and limestone mixture of rutting depth, water stability, marshall stability and flow value, compressive strength and splitting strength. The results show that limestone mixture rutting depth slightly larger than basalt, but the limeatone water stability, marshall stability and flow value, compressive strength and splitting strength is no significant difference compared with the basalt, indicating that good limestone can be used to some extent replace the basalt as coarse aggregate. Study fiber on performance of asphalt mixture, results show that the mixture mixed with fiber water stability, splitting strength are improved, high temperature peroamance, compressive strength are not improved significantly. Basalt fiber cotton mixture is superior to the improvement of basalt chopped fiber and regular basalt fiber, the effect of basalt fiber is worst.