Study On The Performance Of Semi Flexible Pavement Grouting Material Based On Crack Resistance

Semi flexible pavement material(Semi-flexible pavement,SFP)is a highperformance rutting resistant composite material formed by pouring cement based grouting materials into high connectivity void matrix asphalt mixtures.However,cement based grouting materials have problems such as poor volume stability and weak interfacial bonding ability,resulting in cracks in semi flexible pavements,which hinder their engineering use and promotion.Based on the perspective of crack resistance,this thesis takes cement based grouting materials as the research object,and uses a variety of additives and admixtures to obtain the optimal mix ratio of two high-performance cement based grouting materials,the ordinary type and the ultra early strength type;Using steel slag powder to prepare steel slag based expansion agent to solve the cracking problem of semi flexible pavement,and exploring its crack resistance mechanism from a microscopic perspective;The effects of different types of grouting materials on the road performance of semi flexible pavement materials were studied;Using acoustic emission technology,the cracking mechanism of semi flexible pavement materials injected with different types of grouting materials was studied and analyzed.The conclusions are as follows:1.The expansion effect of steel slag based expansion agent is stable and durable,and its compensating shrinkage performance in the later hydration period is better than that of UEA expansion agent.It can also effectively improve the construction applicability of cement based grouting materials.Steel slag based expansion agent is suitable for semi flexible pavement,with an optimal mixing amount of 15% to 20%.When the fineness of steel slag powder is 0.8%,it is most suitable for making steel slag based expansion agent.Through SEM scanning,it was found that it not only can compensate for shrinkage,but also can improve the interfacial bonding strength between cement-based grouting materials and the parent asphalt mixture,significantly improving the low-temperature crack resistance of semi-flexible pavement,achieving a dual crack resistance effect.2.The road performance of semi flexible pavement materials was studied by injecting different types of grouting materials.It was found that adding steel slag based expansion agent can effectively improve the filling rate of semi flexible pavement materials;Injecting the same type of grouting material,the stiffness of the semi flexible pavement becomes larger and larger as the age increases,and the high-temperature stability performance becomes better and better;Injecting super early strength and steel slag based expansion agent grouting materials can effectively improve the crack resistance of semi flexible pavement,while adding steel slag based expansion agent grouting materials is more conducive to improving its later crack resistance;The water stability of semi flexible pavement materials can be better ensured by adding steel slag based expansion agent type grouting materials.3.Using acoustic emission technology,a small beam bending and splitting test was designed to study the cracking mechanism of semi flexible pavement materials after injecting different grouting materials.The addition of steel slag based expansion agent improves the crack resistance of semi flexible pavement materials.When semi flexible pavement materials are damaged,the proportion of tensile damage is dominant;The mechanical damage process of semi flexible pavement materials is correlated with AE parameters at various stages,and the AE signal characteristics can well reflect the damage process of semi flexible pavement materials.