粉煤灰与矿渣、硅灰复掺混凝土干湿循环下抗硫酸盐侵蚀性能研究

Study on Sulfate Erosion Resistance of Concrete Mixed with Fly Ash,Slag and Silica Ash under Dry-wet Cycle

为探索粉煤灰与矿渣、硅灰复掺混凝土干湿循环作用下的抗硫酸盐侵蚀性能,在室内开展了三组掺合料混凝土在3种不同浓度硫酸根溶液侵蚀以及4种硫酸盐溶液侵蚀下的干湿循环和抗压试验。结果表明:掺合料种类对混凝土抗硫酸盐侵蚀能力的影响较大,掺入硅灰能明显提升混凝土抗硫酸盐侵蚀能力,复掺15%粉煤灰+30%矿渣+5%硅灰试验组的抗硫酸盐侵蚀能力最强;硫酸根离子浓度越高,生成的钙矾石和石膏量越多,混凝土的抗侵蚀能力越弱;MgSO_4对混凝土的侵蚀能力强于Na_2SO_4,掺入NaCl能减弱硫酸盐的侵蚀能力,混凝土对四种硫酸盐的抗侵蚀能力大小依次为:5% Na_2SO_4+3.5%NaCl>5% Na_2SO_4>5%MgSO_4+3.5%NaCl>5%MgSO_4。

In order to study the sulfate resistance of concrete mixed with fly ash,slag and silica fume under dry-wet cycling,three groups of concrete with admixtures were tested in laboratory under three different concentrations of sulfate solution and four kinds of sulfate solution.The results showed that the types of admixtures were right.The sulphate resistance of concrete was greatly influenced by silica fume.The sulphate resistance of concrete could be improved obviously by adding silica fume.The sulphate resistance of the test group with 15%fly ash+30%slag+5%silica fume was the strongest.The higher the concentration of sulphate ion,the more ettringite and gypsum produced,the weaker the corrosion resistance of concrete.The corrosion resistance of MgSO4 to concrete was stronger than that of Na2SO4,and adding NaCl could weaken the corrosion resistance of sulfate.The corrosion resistance of concrete to four sulfates was 5%Na2SO4+3.5%NaCl 5%Na2SO45%MgSO4+3.5%NaCl 5%MgSO45%MgSO4+3.5%NaCl 5%MgSO4.