Study On Setting And Hardening Mechanism And Microstructure Of Cement Emulsified Asphalt Concrete

Acted as a new pavement material, cement emulsified asphalt concrete has advantages ofboth cement concrete and asphalt concrete as well as wide application prospects when usingcement and emulsified asphalt as cementing material. In this paper, we carry out a lot ofresearch and tests involved in composition, structure and setting and hardening mechanism ofcement emulsified asphalt concrete based on the domestic and overseas research production.And the contact between performances and micro structure of cement emulsified asphaltslurry were measured by SEM, XRD, IR, MIP and micro hardness tester.The setting and hardening process of cement emulsified asphalt slurry is proceeds fromthe demulsification mechanism, and the hydration process is described by the resistivity test.We established ideal structure model of cement emulsified asphalt concrete, presented adesign idea based on asphalt membrane thickness according to space structure model ofcement emulsified asphalt slurry, and ensured the rigid-flexible performance of cementemulsified asphalt concrete.According to interface structure, composition and performance, there are some importantdifferences between cement concrete, asphalt concrete and cement emulsified asphalt concrete.The micro hardness of slurry is insensitive to the pitch amount under micro hardness test; andit also tells that the micro hardness values changed along with different parts of the sample:the micro hardness of aggregate＞the micro hardness of matrix＞the micro hardness ofinterface. It reflects that the micro hardness reduces at first and increases in the final, and themost weakness part belongs to the interface.XRD result shows that the major ingredients of slurry are C-S-H gel, AFt, AFm, CH andsmall amount of cement particles that did not fully hydrated. The asphalt residues, aggregates,unhydrated cement particles and hydration products could form a space network structurethrough chemistry reaction, and high water cement ratio and high amount of emulsifiedasphalt would have unfavorable influences on pore structure of cement emulsified asphaltslurry. The relationship between mechanical property, durability and microstructure is set upby analyzing the characteristics of hydration product and structure features of inner pores.