海水腐蚀下海砂珊瑚混凝土力学性能变化规律研究

Study on the Change of Mechanical Properties of Sea Sand Coral Concrete under Seawater Corrosion

摘要:

为探究海砂珊瑚混凝土（Sea Sand Coral Concrete，简称SSCC）在海水浸泡下的力学性能变化规律，制备了225个海砂珊瑚混凝土试件，进行了不同浸泡时间下试件的立方体抗压强度、轴压强度、弹性模量试验，并微观分析了其性能变化机理。研究结果表明：腐蚀30d，试件立方体和棱柱体抗压强度有所上升，弹性模量略有下降；腐蚀90d，三者分别下降了19.34%、19.92%和9.48%；腐蚀180d，立方体抗压强度、轴压强度最大降幅分别为24.3%和24.1%，弹性模量降幅为12.1%。SEM分析表明，浸泡前期，SSCC水化产物与Cl^-、SO_4^(2-)反应生成石膏等产物，填充混凝土孔隙，使得强度增加；浸泡中后期，腐蚀产物逐渐堆积引发微裂缝扩展，导致强度下降。腐蚀后SSCC应力应变曲线峰值应力下降，峰值应变增大。基于试验数据，建立了SSCC力学性能时变公式，研究结果可为海洋环境下SSCC的工程应用提供参考。

Abstract:

To investigate the mechanical performance changes of Sea Sand Coral Concrete (SSCC) under seawater immersion, 225 SSCC specimens were prepared, and tests were conducted on the cube compressive strength, axial compressive strength, and elastic modulus of specimens after different immersion periods, along with a microscopic analysis of the mechanisms behind the performance changes. The results show that after 30 days of corrosion, the cube and prismatic compressive strengths of the specimens increased slightly compared to day 0, while the elastic modulus decreased slightly; after 90 days of corrosion, the three values decreased by 19.34%, 19.92%, and 9.48%, respectively; after 180 days of corrosion, the maximum reductions in cube compressive strength and axial compressive strength were 24.3% and 24.1%, and the elastic modulus decreased by 12.1%. SEM analysis indicated that in the early stage of immersion, SSCC hydration products reacted with Cl^- and SO_4^(2-) to form gypsum and other products, filling the concrete pores and increasing strength; in the mid-to-late stages of immersion, corrosion products gradually accumulated, causing microcrack propagation and resulting in strength reduction. After corrosion, the peak stress in the SSCC stress-strain curve decreased, and the peak strain increased. Based on the experimental data, a time-varying formula for SSCC mechanical properties was established. The results provide a reference for the engineering application of SSCC in marine environments.