高温后珊瑚海水海砂混凝土力学性能试验研究∗

Experimental Study on Mechanical Properties of Coral Seawater Sea Sand Concrete after High Temperature

摘要:

为研究高温后珊瑚海水海砂混凝土（CSSC）的力学性能，设计制作了 30 个 CSSC 试件，进行常温与高温后轴心受压和静力受压弹性模量试验。通过试验观察了试件高温后的表观变化和轴心受压破坏形态，获取了轴心受压全过程应力—应变曲线、弹性模量及烧失率等参数，深入高温后 CSSC 微观结构变化机制，得到了受火温度对 CSSC 力学性能的影响规律，揭示了高温作用后 CSSC 的力学性能退化机理。结果表明：随着受火温度的增加， CSSC 力学性能不断劣化。T=200 ℃时 CSSC 轴心抗压强度和弹性模量分别比常温时下降了 26.52 %，6.19 %，混凝土具有较好的力学性能；T=400 ℃时 CSSC 弹性模量下降迅速，弹性模量损失率为 65.48 %，但与 T=200 ℃相比混凝土轴心抗压强度上升了 6.4 %；T=600 ℃时 CSSC 轴心抗压强度下降迅速，强度损失率为 66.74 %；T=800 ℃ 时 CSSC 破坏严重，已无法测得有效的弹性模量。

Abstract:

To study the mechanical properties of Coral Seawater Sea Sand Concrete (CSSC) after exposure to high temperatures, axial compression and static compression elastic modulus tests were conducted on 30 CSSC specimens at room and high temperatures. The axial compression failure patterns and apparent changes of the specimens after exposure to high temperatures were observed, and parameters such as the complete stress-strain behavior under axial compression, elastic modulus, and weight loss rate were obtained. In conjunction with an in-depth analysis of the mechanisms of microstructural changes in CSSC after exposure to high temperatures, the study explored the influence of fire temperature on CSSC's mechanical properties and revealed the degradation mechanism of these properties after high-temperature exposure. The results demonstrated a progressive decline in the mechanical properties of CSSC as the fire temperature increased. At 200 ℃ , compared to specimens at room temperature, the axial compressive strength and elastic modulus of CSSC decreased by 26.52% and 6.19%, respectively, indicating good mechanical properties. At 400 ℃ , the elastic modulus of CSSC decreased rapidly, with a loss of 65.48%, but its axial compressive strength increased by 6.4% compared to specimens at 200 ℃. At 600 ℃, the axial compressive strength of CSSC exhibited a rapid decline, with a strength loss rate of 66.74%. The CSSC was severely damaged at 800 ℃ , making it impossible to measure its effective elastic modulus.