Deng Dehua

Physical structure of hardened cement asphalt paste for the slab track of high-speed railway

In the present paper, through the calculation based on Powers theories and models and the phase analyses by XRD, SEM and EDAX, the phase composition and microstructure of hardened cement asphalt pastes were studied. The results showed that the phase composition and microstructure of hardened cement asphalt pastes are dependent on both asphalt/cement and water/cement ratios. The two physical models for the microstructure of hardened cement asphalt pastes with different asphalt/cement ratios are proposed. I type structure model is characterized by the asphalt matrix and the disperse phases of cement hydrates. II type structure model is characterized by the matrix of cement hydrates and the disperse asphalt agglomerates. These models will contributed to the researches of the mechanical properties and degradation mechanism of cement asphalt mortars.

Micro-analyze on development of the static mechanical properties of CRTS I type cement emulsified asphalt mortar

The development of static mechanical properties of CRTS II type cement emulsified asphalt (CA) mortar was studied. The specimens were made with the fresh mortar used in Jiangxi section of HU-KUN High Speed railway. The asphalt in mortar was extracted by Trichloroethylene at different age. Then, MIP (Mercury intrusion method) and NMR (Nuclear Magnetic Resonance) were employed to analyze the pore structure of mortar, and the cement hydration was analyzed by means of TGA (Thermogravimetric Analysis). According to the results, at the age of 28 days the compressive strength and elasticity modulus had reached the value offered in standard. The mechanical properties had been increasing with the progress of age due to the cement hydration, causing the pore refinement. However, the increasing rate became quite slow after 42 days. It could found that the film formation of emulsified asphalt was relative quick and reach stable just after 7 days.