Mechanical properties and dynamic constitutive relation of lightweight shale ceramsite concrete

To study the strength increasing rule of LWSCC in the process of freezing construction, some specimens were placed in cryogenic boxes at different subzero temperatures for curing, and the others were used as a control group for standard curing. After standard curing for 28 days, the specimens were placed in cryogenic boxes at different subzero temperatures for 1 day, and then the specimens were subjected to quasi-static loading and split Hopkinson pressure bar (SHPB) dynamic impact tests. Results showed that LWSCC had a stronger anti-freezing ability than the ordinary concrete and the strength growth was sensitive to the curing temperature. As the curing temperature decreased, the increasing rates of the compressive and tensile strengths became slow. The quasi-static and dynamic mechanical experiments showed that the strength of LWSCC was substantially enhanced when subjected to cryogenic temperatures after standard curing. Cryogenic LWSCC exhibited an obvious strain rate effect and impact resistance. A two-factor incremental model of the dynamic stress intensity factors and the dynamic constitutive equation of LWSCC in cryogenic temperatures were constructed. The conclusions obtained in the study provide a theoretical basis for the design of impact-resistant structures in cold areas.