纳米SiO2和高炉矿渣粉对OPC-CSA复合修补砂浆耐盐渍土侵蚀性能的影响

Effects of Nano-SiO2 and Granulated Blast Furnace Slag Powder on Corrosion Resistance of OPC-CSA Composite Repair Mortar to Saline Soil

采用复合盐-干湿循环和半浸泡相结合的方法模拟盐渍土侵蚀环境,以试件表观损伤、质量变化、相对动弹性模量、抗压耐蚀系数以及氯离子含量为评价指标,研究了纳米SiO2和粒化高炉矿渣粉对普通硅酸盐水泥-硫铝酸盐水泥(OPC-CSA)复合修补砂浆耐盐渍土侵蚀性能的影响,并结合X射线衍射仪(XRD)分析了试样浸泡部分和干燥部分的物相组成。结果表明:掺入1%纳米SiO2和10%矿渣粉(质量分数)的试件经干湿循环150次后未出现明显损伤,纳米SiO2和适量矿渣粉可以提高砂浆密实度,增强OPC-CSA复合修补砂浆的耐盐渍土侵蚀性能;试件浸泡部分以化学侵蚀为主,侵蚀产物为钙矾石和Friedel′s盐,干燥部分以物理腐蚀为主,结晶物质为硫酸钠。

The corrosion environment of saline soil was simulated by the method of composite salt dry-wet cycle and semi immersion.The effects of nano-silica and granulated blast furnace slag powder on the corrosion resistance of ordinary Portland cement-sulphoaluminate cement(OPC-CSA)composite repair mortar were studied.The appearance damage,mass change,relative dynamic elastic modulus,compressive corrosion resistance coefficient and chloride ion content were taken as the evaluation indexes.And the phase composition of the immersed portion and the drying portion of the samples was analyzed by XRD.The results show that there are no obvious damages on the specimens mixed with 1%nano-SiO 2 and 10%slag powder(mass fraction)after 150 cycles.It indicates that nano-SiO 2 and appropriate amount of slag powder improve the compactness of mortar,and then enhance the corrosion resistance of OPC-CSA composite repair mortar to saline soil.The immersed portion of specimen is mainly subject to chemical erosion,and the erosion products are ettringite and Friedel′s salt.The drying portion is mainly subject to physical corrosion,and the crystalline substance is sodium sulfate.