高渗透压-硫酸盐侵蚀下混凝土时空劣化

为了模拟研究混凝土海水环境下的侵蚀损伤及劣化规律，采用质量分数10% Na₂SO₄溶液对混凝土试样进行不同渗透压和不同时长下的室内侵蚀试验. 结合微米压痕试验、CT扫描试验和电子显微镜扫描试验，对高渗透压-硫酸盐耦合侵蚀作用下混凝土的侵蚀损伤及微观力学性能进行研究. 试验结果显示，渗透压加速了离子迁移，主要起到了促进化学侵蚀作用. 渗透压越大，混凝土化学损伤速率越快，侵蚀深度越深；骨料与砂浆胶结处是易侵蚀、易破坏的薄弱点；混凝土内部孔隙易生成水化产物，高渗透压下容易生成大量短柱状石膏晶体及细密的针状钙矾石晶体.

Spatiotemporal deterioration of concrete under high osmotic pressure and sulfate attack

10% Na₂SO₄ with mass fraction solution was used to carry out indoor corrosion tests under different osmotic pressures and different lengths of concrete samples, in order to simulate the corrosion damage and degradation of concrete under seawater environment. Combined with micro indentation test, CT scanning test and SEM test, the corrosion damage and micromechanical properties of concrete under the action of high osmotic pressure sulfate coupling corrosion were studied. Experimental results show that osmotic pressure accelerates ion migration and mainly promotes chemical erosion. The higher the osmotic pressure, the faster the chemical damage rate of concrete, the deeper the erosion depth; the cementation of aggregate and mortar is the weak point which is easy to be eroded and destroyed; the hydration products are easy to form in the internal pores of concrete, and more short column gypsum crystals and more fine needle ettringite crystals are formed under higher osmotic pressure.