硫酸和硫酸钠混合溶液对砂浆的腐蚀作用

Corrosion of Mortars in Sulfuric Acid and Sodium Sulfate Solution

摘要:

用普通硅酸盐水泥和硫铝酸盐水泥的混合水泥以及磨细高炉矿渣和聚合物乳液配制了4种水泥砂浆,研究了这些水泥砂浆试样在1%(质量分数,下同)硫酸加10%硫酸钠的混合溶液中浸泡不同时间后的质量变化和强度变化.结果发现,混合溶液对4种水泥砂浆都具有强烈的腐蚀作用.磨细高炉矿渣能显著提高砂浆的耐腐蚀性能;进一步添加聚合物乳液(聚胶比为10%),则砂浆的抗表面剥落性能有很大改善,其中尤以苯丙乳液与丁苯乳液的混合乳液改性砂浆效果更好,但添加聚合物乳液会导致砂浆的抗压强度大大降低.此外,水泥砂浆试样在混合溶液及清水中浸泡后,它们的抗压强度比值要比它们的抗折强度比值对硫酸/硫酸钠腐蚀介质更为敏感.

Abstract:

In this paper,four different cement mortar specimens were prepared with mixed cement of Portland cement and calcium sulfoaluminate cement.They are all modified with ground granulated blast furnace slag(GGBFS) and latex.The change of weight and strength of the specimens that are immersed in solution of 1% sulfuric acid plus 10% sodium sulfate were measured.The results show that the acidic sulfate solution has strong corrosive effect on all 4 mortars.GGBFS can significantly improve the resistance of cement mortar.Adding polymer with the polymer-binder ratio of 10% to the mortar with GGBFS,the scale off of the specimens exposed to the mixed solution were much improved,among which the latex blend of styrene/acrylate copolymer and butadiene/styrene copolymer modified mortar exhibit the best effect.However,the compre-(ssive) strength of the mortars with latex is much lower than that without latex.Furthermore,the compressive strength ratio of the specimens immersed in the mixed solution and water is more sensitive than the flexural strength ratio.