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To study the dynamic mechanical characteristic of steam cured concrete and self-compacting concrete bonding interface, a split Hopkinson pressure bar (SHPB) test was used to evaluate the dynamic properties of concrete with a bonding interface. The failure pattern and the characteristics of stress-strain curves and a constitutive model of concrete with a bonding interface were discussed. The results show that the impact destructions are associated with two forms of failures, i.e., the interface separation failure and concrete crushed failure. In interface separation failure, the peak stress, dynamic increase factor (DIF), peak strain, and impact toughness of concrete with a bonding interface increase with the increase of strain rate, and the concrete with a bonding interface shows a stronger strain rate sensitivity. In concrete crushed failure, there exist debonding deformation and crush deformation exist simultaneously. With the increase of strain rate, the accumulation and development of crack at the interface could make the interface zone play an energy relieving role in concrete with a bonding interface. The peak stress and the DIF of concrete with a bonding interface remain unchanged, while the peak strain and impact toughness both increase. The calculated data by the established dynamic constitutive model are similar to the experimental results, especially before the ultimate state of strain stress curves.

In this paper, ecological cement-based materials were prepared based on a large amount of EMR to provide a potential scheme for accelerating the digestion of EMR. Firstly, the performance change from low consumption and harmless pretreatment of EMR was discussed. Then the mechanical properties and water resistance of cement mortar pretreated with EMR were studied. Finally, the corresponding economic and environmental effects were analyzed. The results show th.at the particle size of EMR becomes smaller after lime and ball milling, and the phase of (NH4)2SO4 in EMR transforms into gypsum phase. The removal rates of Mn2+ and NH4+--N reached 98.69% and 96.46%, realizing the harmless treatment of EMR. When the content of EMR reaches 70% and the cement-sand ratio is 1:2, the mechanical properties and durability of cement-based materials are good. Compared with M15 mortar prepared with pure cement, EMR-cement mortar can achieve 17.6% economic saving and 36.8% greenhouse gas emission reduction. The research results can provide important technical support for the application of EMR in roadbed reinforcement and road cement stabilization base, and realize the efficient and low-carbon utilization of EMR waste. [ABSTRACT FROM AUTHOR]