Experimental Study On Mix Ratio Parameters Optimizatiaon Of Roller Compacted Asphalt Concrete Based On Surface Theory

With the scale of infrastructure construction expanding in China,hydraulic asphalt concrete seepage control technology has been rapidly developed.Roller compacted asphalt concrete core dan is widely used in the world today.In practical engineering applications,the design and selection of m ix ratio is one of the key issues for research.At present,the commonly method used in the mix ratio design of hydraulic asphalt concrete in China is to select the maximum aggregate size,gradation index,filler dosage and asphalt-aggregate ratio parameters on the basis of the asphalt concrete mortar theory and the engineering experience,with the use of the orthogonal method to preliminarily simulate the array mix ratio.The workload of design by this method is too big since it requires mix ratio design test under different construction factors with no unifi ed regularity.Therefore,the research in this paper mainly studies the internal law of the mix ratio of hydraulic asphalt concrete under different temperature conditions by taking the surface theory of asphalt concrete as basis.Based on the theory of maximum compactness curve,this paper firstly studies the influence of the maximum aggregate size of 19 mm,gradation index and filler dosage on the compactness of hydraulic asphalt concrete aggregate by indoor full-graded aggregate packirng density test,coarse aggregate packing density test and coarse aggregate watering packing density test.The gradation design of alkaline limestone aggregate gradation for hydraulic asphalt concrete is achieved based on the test of coarse aggregate with water accumulation density.The test results are accurate with minute errors.Dmax=19 mm,r=0.40,F=12%are recommended for the densest aggregate gradation parameters,and the densest aggregate gradation is not affected by construction factors.Secondly,as per the densest aggregate gradation,the indoor splitting tests were carried out based on five temperatures(T=5??10??15??20??25?),five oil-stone ratios(B=6.0%,6.3%,6.6%,6.9%,7.2%).The results were analyzed by single factor analysis and entropy method.The single factor analysis method was applied to analyze the porosity,indirect tensile strength and indirect tensile strain under different temperature and oil-stone ratio.The optimum oil-stone ratio was 6.6%-6.9%.The calculation model of Entropy Method is based on objectively giving three index weights and calculating the optimum oil-stone ratio under different temperature conditions.The calculation results are consistent with the range of the optimum oil-stone ratio obtained by single factor analysis method.Then the optimum oil-stone ratio curve B=0.O0001333T3-0.00543T2+0.03952T+6.84 based on different temperature conditions is regressed by linear regression equation.In addition,by the study of transverse displacement and Poisson's ratio,it is found that transverse displacement and Poisson's ratio are more sensitive to temperature conditions than oil-stone ratio,and positively correlated with temperature.Finally,according to the research results and a pumped storage power station project in Qiongzhong,Hainan(annual average temperature 22.5?),with the performance tests including the trabecular bending,tension,compression,water stability and permeability carried out to verify whether the test results of the performance indicators meet the requirements of the engineering design indicators.The above conclusions provide a reference basis for the design of hydraulic asphalt concrete mix ratio in actual projects.