冻融循环后轻骨料混凝土双轴拉(劈拉)压强度试验和破坏准则研究

EXPERIMENTS AND FAILURE CRITERION OF LIGHTWEIGHT AGGREGATE CONCRETE AFTER FREEZE-THAW CYCLING UNDER BIAXIAL STRESS OF SPLITTING TENSION AND COMPRESSION

进行海水中不同冻融循环次数后轻骨料混凝土双轴拉(劈拉)压状态下的强度试验,考察试件的破坏形态和表面裂缝的走向特征。根据试验结果分析双轴拉压状态下的极限抗压、劈拉强度随冻融循环次数和应力比的变化规律。并在此基础上,建立不同冻融循环次数后主应力空间的破坏准则和考虑冻融循环影响的八面体应力空间的统一破坏准则,为寒冷海洋环境条件下轻骨料混凝土结构在经受拉压组合荷载作用时的强度分析提供试验和理论依据。

The strength experiments of lightweight aggregate(LWA) concrete after freeze-thaw cycling in seawater under biaxial splitting tension and compression stress are preformed.The failure characteristics of specimens and the direction of superficial cracking are researched.Based on the test resultst,he ultimate compressive and splitting tensile strengths varying with freeze-thaw cycles and stress ratio are analyzed.The failure criterion expressed in terms of principal stress after different freeze-thaw cycles and the unified failure criterion in octahedronal stress space considering of freeze-thaw cycling influence are proposedr,espectively,which can provide the experimental and theory foundations for strength analysis of LWA concrete structures subject to tension and compression load in cold marine environment.