Construction High-performance Cement Asphalt Mortar And Concrete By Using Trial Mixing And Variance Analysis Method

Cement asphalt mortar and concrete,which is a new environmental protection pavement materials,have a good application prospect.At present,the surfactant alone can improve the compatibility of cement emulsified asphalt to a certain extent.Therefore,cement emulsified asphalt can be mixed directly and evenly with a small amount of external water.However,the cement asphalt mortar has some problems,such as: setting time is too long,poor volume stability,premature demulsification of emulsified asphalt,etc.At the same time,the cement asphalt concrete is made of these mortars also has problems of indirect tensile strength dynamic stability,low Marshall stability and low volume stability,etc.In view of the above problems,this study selects a variety of different surfactants,accelerating agents and retarders and asphalt base materials to prepare different cement asphalt mortar,and identifies its physical-mechanical characteristics and engineering application prospects.Specifically: naphthalene-based superplasticizer(NSP),lignin sulfonate(LS)and other two surfactants,gypsum(CSH),calcium chloride(CC),calcium formate(CF)and other three quick-setting agents,Polyacrylamide(PAM),sea vegetable powder(SP),sodium gluconate(SG)and other three organic retarders,and cationic emulsified asphalt(CAE),modified emulsified asphalt(MAE).Nine kinds of freshly mixed cement asphalt mortars are prepared through the above materials,and the best performance cement asphalt mortars are mixed with dense graded aggregates to make three types of cement asphalt concrete.The related test indexes show that the newly mixed cement asphalt mortar and cement emulsified asphalt concrete overcome the above problems and have better performance.The main research work includes:1.Through viscosity,setting time,volume change,compressive strength,tensile strength and other indicators,the performance of the newly mixed cement paste was analyzed.The effect of each reagent on the hydration reaction of cement was preliminarily investigated,and the action mechanism of accelerating agent and retarding agent on the hydration reaction of cement was put forward.The results showed that increasing the concentration of calcium ions can accelerate the hydration reaction of cement,but sodium gluconate can consume a large amount of calcium ions,which had a strong retarder effect on the newly mixed cement slurry and reduces the volume stability and mechanical properties of the slurry.2.According to the selected surfactant properties,cement asphalt mortar(CA mortar)trial mix was carried out to determine the mixing range of accelerating and retarder.Then the properties of cement asphalt mortar were analyzed by viscosity,slump flow rate,setting time,volume change,compressive strength,tensile strength.Finally,it is successful that the effects of surfactants,accelerators and retarders on the promotion of cement emulsified asphalt mortar were revealed.3.After the CA mortar with the best working performance was determined,it was mixed with appropriate dense gradation aggregate to make cement asphalt concrete(CAC)and mixed for trial.Then the performance of CAC was compared and studied through Marshall stability test,indirect tension test,Fort Kenta fly test,wheel rutting test and volume stability test.The research results showed that the minimum rutting deformation of CAC within 15 h is within 3.5mm,the Marshall stability of 7d is 28～50k N,and that of 28 d can reach 70 k N.According to the relevant tests of fresh cement paste,CA mortar and CAC,the main conclusions are as follows:1.gypsum,calcium chloride,polyacrylamide and seaweed powder can well solve the compatibility problems of cement emulsified asphalt and the problems of long setting time.2.The new CA mortar forming method and CAC mixing ratio reduce the consumption of emulsified asphalt,which is more conducive to the formation of overlapping space structure between cement and emulsified asphalt.3.Within a relatively short age,the mechanical properties,durability and volume stability of the three kinds of newly mixed CAC are relatively good,which is conducive to shortening the construction period of CAC in the project and saving the construction cost.