基于微结构改造的水泥混凝土材料耐久性试验研究

为增强水泥混凝土材料耐久性,研究基于混凝土材料多孔特点,通过在混凝土拌制过程中掺加纳米硅灰和有机硅乳液的方法,提高混凝土材料的密实度和抗渗性能。通过测试改造前后混凝土的早期抗裂性能、氯离子渗透性能、碳化性能、抗硫酸盐侵蚀性能以及抗冻性能,来评价改造前后混凝土耐久性变化情况,并通过压汞试验绘制孔径分布曲线,从微观孔结构角度解释混凝土宏观耐久性变化的原因。研究结果表明,通过掺加纳米硅灰和有机硅乳液的方法,可以比较全面的改善混凝土材料的宏观耐久性。微观孔结构测试结果表明,由于混凝土的孔径分布曲线得到了优化,经过改造后的混凝土100 nm以下的小孔数量明显增多。研究成果为混凝土材料的应用提供参考。

Micro-structural improvement-based experimental study on durability of cement concrete material

In order to enhance the durability of cement concrete，the enhancements of compactness and impervious performance of the concrete material are studied through the method of mixing nano-silica fume and organic silicone emulsion into the concrete in accordance with the porous characteristics of the concrete material． Through testing the early cracking resistance，chloride permeability，carbonization property，sulfate resistance and frost resistance before and after the improvement，the variation of the concrete durability before and after the improvement is evaluated，while the causation of the macroscopic-variation of the concrete is explained from the aspect of the microscopic structure by drawing pore-size distribution curve through mercury injection experiment． The study result shows that the macroscopic durability of the concrete material can be fully improved through the method of mixing nano-silica fume and organic silicone emulsion into the concrete，for which the microscopic structure testing result indicates that the improvement mainly obtained from the optimization of the pore-size distribution curve of the concrete along with obvious increase of the number of the small sized pores below 100 nm． The study result can provide a reference for the application of the concrete material.