Abstract

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.

摘要

为研究LWSCC在冷冻施工过程中的强度增加规律，将部分试件置于不同零下温度的低温箱中养护，其余试件作为对照组进行标准养护。标准养护28天后，将试件置于不同零下温度的低温箱中1天，然后对试件进行准静态加载和分裂霍普金森压力棒（SHPB）动态冲击试验。结果表明，LWSCC比普通混凝土具有更强的抗冻能力，强度增长对养护温度敏感。随着固化温度的降低，抗压强度和抗拉强度的增加速度变慢。准静态和动态力学实验表明，在标准固化后经受低温时，LWSCC 的强度显着增强。低温LWSCC表现出明显的应变率效应和抗冲击性。建立了动态​​应力强度因子的二因子增量模型和LWSCC在低温下的动态本构方程。研究得出的结论为寒冷地区抗冲击结构的设计提供了理论依据。建立了动态​​应力强度因子的二因子增量模型和LWSCC在低温下的动态本构方程。研究得出的结论为寒冷地区抗冲击结构的设计提供了理论依据。建立了动态​​应力强度因子的二因子增量模型和LWSCC在低温下的动态本构方程。研究得出的结论为寒冷地区抗冲击结构的设计提供了理论依据。