冻融循环后粉煤灰陶粒混凝土定侧压下的强度和变形性能试验研究

STRENGTH AND DEFORMATION PROPERTIES OF LYTAG CONCRETE UNDER LATERAL STRESS AFTER FREEZE-THAW CYCLE

利用混凝土静、动三轴试验系统,完成了粉煤灰陶粒混凝土立方体试件在4组不同冻融循环次数、4种恒定侧压下的双轴压压强度和变形性能试验。考察了不同侧压应力水平下试件的破坏形态和试件表面裂缝分布及走向特征。测量了4种侧压应力水平下的极限抗压强度及两个加载方向的应变值,并根据试验结果系统分析了定侧压下粉煤灰陶粒混凝土双轴压压极限强度和变形性能(包括峰值应变、应力-应变关系曲线、弹性模量)随冻融循环次数和侧压应力水平的变化规律,建立了考虑冻融循环次数和侧压应力水平的主应力空间的双轴压压强度准则,为寒冷海洋环境条件下粉煤灰陶粒混凝土结构在经受双轴压压荷载作用时的强度分析提供试验和理论依据。

The compressive strength and deformation tests for Lytag concrete specimens are carried out under 4 kinds of lateral stress levels and 4 stages of freeze-thaw cycle in a concrete static and dynamic tri-axial test system. The failure modes and superficial cracking characteristics of specimens are reported. The ultimate compressive strength and strain in the two loading directions under 4 different lateral stress levels, 0, 0.25 fc, 0.50 fc, and 0.75 fc after 0, 25, 50, and 75 freeze-thaw cycles are measured. Based on the test data, the biaxial compressive strength and deformation properties of Lytag concrete varying with freeze-thaw cycles and lateral stress levels are systematically studied. Additionally, the biaxial compressive strength criterion for Lytag concrete in principal stress space is developed considering the effects of freeze-thaw cycle and lateral stress, which establishes the experimental and theoretical foundations for strength analysis of Lytag concrete structures subject to biaxial compressive load in cold marine environment.