摘  要：分析了纳米CaCO₃掺入量、盐碱浓度等因素对混凝土在盐碱-干湿循环后的强度及耐久性的影响，通过150次的干湿循环，研究了混凝土抗压强度耐蚀系数、质量损失率、相对动弹性模量等耐久性指标随干湿循环的变化规律。试验结果表明，掺入1%的纳米CaCO₃可以使28 d混凝土试件获得较高的抗压强度，盐碱-干湿循环条件下2%掺量的纳米CaCO₃混凝土试件强度下降最低。纳米CaCO₃对混凝土干湿循环中后期的耐久性有明显的提高作用，其最佳掺量为2%，掺量超过2%后则会造成耐久性指标的下降。盐碱浓度对纳米混凝土耐久性的影响随干湿循环次数的增加而增大，且相对动弹模量较质量损失率指标更易受盐碱浓度的影响。
Abstract: The strength and durability of concrete after saline-alkali-dry-wet cycle were analyzed around the factors such as nano-CaCO₃ content and saline-alkali concentration. Through the maximum 150 cycles of dry-wet cycle, the changing rules of durability indexes such as compressive strength, corrosion resistance coefficient, mass loss rate and relative dynamic elastic modulus of concrete with dry-wet cycle were studied. The experimental results show that 1% nano-CaCO₃can increase the compressive strength of 28 d concrete specimens, and 2% nano-CaCO₃ can reduce the strength decrease of concrete specimens at the lowest level under saline-alkali-dry-wet cycling conditions. The durability of concrete could be improved by nano-CaCO₃ in the middle and late stage of dry-wet cycle, and the optimum content of nano-CaCO₃ is 2%. As the content of nano-CaCO₃ exceeds 2%, the durability index will decrease. The influence of saline-alkali concentration on the durability of nano-concrete increases with the growth of wet-dry cycles and the relative dynamic modulus of elasticity is more sensitive to the influence of saline-alkali concentration than the mass loss rate index.