渗透结晶反应对水泥基材料孔隙率的影响

Effect of capillary crystalline reaction on repair of voids and cracks in cement-based materials

为减少已存在于水泥基材料中孔隙,从而降低其渗透性和改善材料的耐久性,本研究采用浸泡法研究硅酸乙酯、无机铵盐、硅酸盐等对孔隙堵塞修复作用,以吸水率、力学强度和孔隙率等为考察指标,并结合微观分析与理论研究。结果表明:硅酸乙酯和磷酸氢二铵降低了吸水率约2倍;弱碱性硅溶胶浸泡后抗折抗压强度分别提高了24.19%和17.68%,硅酸乙酯抗折抗压强度提高了14.57%和2.69%;涂刷活性物质后显著地降低10-100 nm的过渡孔和100-1000 nm的毛细孔。机理分析表明:活性物质与氢氧化钙发生反应生成不溶性物质堵塞了孔隙,SEM表征也得到了证实。上述结果表明渗透结晶反应能够有效降低水泥基材料孔隙率。

To block or reduce porosity existed in cement base material, thus reducing its permeability and improving the durability of materials, the paper studied the effect of ethyl silicate, inorganic ammonium salt and silicate on pore jams repairing function by soaking method, and used the water absorption, mechanical strength and porosity as examining index. In addition, the paper also combined with microscopic analysis and theoretical research. The results showed that TEOS and diammonium phosphate reduced the water absorption rate by about 2 times. The compressive strength of weakly alkaline silica was increased by 24.19% and 17.68%, respectively and the compressive strength of ethyl silicate increased by 14.57% and2.69%, respectively. After coating the active material, the transition hole of 10-100 nm and the capillary of 100-1000 nm were significantly reduced. The mechanism analysis showed that the active substance reacting with the calcium hydroxide generated insoluble material and the pore volume was blocked. The SEM characterization was also confirmed the above mentioned analysis. The effect of capillary crystalline reaction can effectively reduce the porosity of cement based materials.