Test Study On Mix Ratio Selection And Creep Performance Of Hydraulic Asphalt Concrete

With the enhancement of the national economy,modern water conservancy projects are developing with the aspiration for large scale,high dam,high durability,environmental protection and high economic value.With many advantages such as environmental protection,frost resistance,seepage resistance,good durability and fast construction speed,hydraulic asphalt concrete anti-seepage engineering has become the preferred form of many water conservancy projects.At present,research on hydraulic asphalt concrete is mainly focused on the mechanical properties.However,there are still many deficiencies in the design and selection of mix proportion,deformation performance and influencing factors,the use of additives,and construction quality control.These aspects are of great significance for the development of hydraulic asphalt concrete.Taking hydraulic asphalt concrete as the research object,this paper uses indoor laboratory method to study the optimization method and creep performance of asphalt concrete mixture ratio,and will provide useful information for future related research on and engineering application of hydraulic asphalt concrete.First of all,this paper summarizes the material and structural characteristics of hydraulic asphalt concrete impervious works,and analyzes the existing design methods for hydraulic asphalt concrete mix proportion.On this basis,adopting the orthogonal test scheme and according to the existing experimental research results and engineering experience,this research project designed a total of 9 groups of orthogonal test schemes.For grading index,filler content and bitumen aggregate ratio,3 levels were adopted: gradation index is 0.35,0.38 and 0.41,filler content is 13%,15% and 17%,and ratio of bitumen aggregate is 6.6%,6.9%,7.2%.Secondly,Marshall stability and flow test,uniaxial compression test,thermal stability test,water stability test,tensile test,trabecular bending test,splitting test and density test of 9 groups of hydraulic asphalt concrete were conducted.The experimental results of 9 groups of Marshall stability,flow value and uniaxial compression strength and the other corresponding tests were obtained.The test results of 9 groups of mix ratio asphalt concrete were analyzed by the method of extreme difference analysis.It is found that the effect of the bitumen aggregate ratio on most of the test results is greater than the influence of the filler content and the gradation index.The optimum mix ratio is 0.38 of gradation index,15% of filler and 6.9% for the bitumen aggregate ratio.In the end,this paper introduces the viscoelastic material and analyzes its performance differences under different temperature and load conditions.On this basis,a total of 9 groups of creep tests of three stress levels,i.e.,0.5MPa,0.75 MPa and 1MPa,were conducted under three temperature conditions of hydraulic asphalt concrete at 10℃,20℃ and 30℃.The corresponding creep curves were obtained from the experimental results,and the steady creep rate under different temperatures and stresses was fitted.The creep curve analysis shows that at the same stress level,when the temperature rises,the first stage of the asphalt concrete creep curves has shorter duration but increased strain rate.The strain and the steady creep rate of K have increased during the first phase.Within the same time period,the whole deformation of asphalt concrete increases greatly.At the same temperature,with the increase of load,the deformation rate of asphalt concrete increases,and it will enter the steady creep stage at a large deformation rate.Within the same time period,the asphalt concrete will produce greater deformation.The fitting lines under different temperature and load conditions are obtained from the steady creep rate,and the fitting results have good regularity.