【摘要】 研究了含裂缝硬化水泥净浆、砂浆和混凝土试件中的渗透溶蚀过程及其对水泥基材料细观结构的影响。结果表明:在裂缝宽度和水力梯度相近情况下,硬化水泥净浆裂缝试件渗透性最高,而混凝土裂缝试件渗透性最低;在渗透的初始阶段,水泥基材料存在裂缝自愈过程,其中砂浆裂缝试件的自愈作用最大,而硬化水泥净浆裂缝试件的自愈作用最小;水泥基材料的渗透过程会导致硬化水泥浆体中Ca2+的溶出,破坏水泥石细观结构;当渗透速率较小,水泥基材料裂缝表面粗糙容易附着CaCO3晶体时,硬化水泥浆体中溶出的Ca2+可能与溶于水中的CO32–结合形成CaCO3结晶而成为混凝土裂缝自愈的原因之一。更多还原

【Abstract】 The water permeating and leaching processes of cracked cement paste, mortar and concrete specimens were investigated, and the effects of these processes on the microstructure were studied. The results show that under a given hydraulic gradient,the permeability order from big to small in specimens with the same crack widths is cement paste, mortar, concrete. The cracks in the cementitious materials autogenously heal during the permeating and leaching processes, and the healing extents for the specimens are in the order of mortar, concrete, cement paste. The permeating process results in the leaching out of Ca2+ ions from the hardened ce- ment paste, which leads to the damage of the structure of the hardened cement paste. When the permeation is slow and the crack walls of the specimens are rough, which is favorable for CaCO3 crystallization, the Ca2+ ions dissolved from the hardened cement paste may combine with the CO32– ions in the water, and crystalline CaCO3 forms, which is one of the causes of the autogenous healing of the cracks in the cementitious materials.更多还原