提高铁路混凝土在盐类结晶环境下的抗侵蚀能力研究

为提高铁路混凝土在盐类结晶环境下的抗侵蚀能力,以隧道衬砌部位混凝土为研究对象,考察了掺入不同加量的纳米SiO2和引气剂GEM对混凝土质量损失率、相对动弹性模量以及抗压强度耐蚀系数的影响。结果表明：在硫酸盐干湿循环实验条件下,纳米SiO2的加入能够有效降低混凝土试件的质量损失率,并使相对动弹性模量和抗压强度耐蚀系数得到提高,纳米SiO2可以有效提高铁路混凝土的抗硫酸盐侵蚀能力,并且纳米SiO2的加量越大,效果越好。当SiO2的加量20kg/m3时,随着引气剂GEM加量的不断增大,混凝土试件的抗硫酸盐侵蚀能力进一步增强,当引气剂GEM的加量为0.05kg/m3时,混凝土试件在经过180次干湿循环后的质量损失率最小(仅为0.26%),相对动弹性模量(95.9%)和抗压强度耐蚀系数(0.919)最大。纳米SiO2和引气剂GEM的加入能够显著改善铁路混凝土在硫酸盐结晶环境下的抗侵蚀能力。

Study on improving corrosion resistance of railway concrete in salt crystallization environment

In order to improve the corrosion resistance of railway concrete in salt crystallization environment, the effects of different amounts of nano-SiO2 and air entraining agent gem on the mass loss rate, relative dynamic modulus of elasticity, compressive strength and corrosion resistance coefficient of concrete were investigated. The results show that: under the condition of sulfate dry wet cycle experiment, the addition of Nano-SiO2 can effectively reduce the mass loss rate of concrete specimens, and improve the relative dynamic modulus of elasticity and the corrosion resistance coefficient of compressive strength, nano-SiO2 can effectively improve the sulfate corrosion resistance of railway concrete, and the greater the amount of nano-SiO2, the better the effect. When the dosage of SiO2 is 20kg / m3, the sulfate resistance of concrete specimen is further enhanced with the increasing dosage of gem. When the dosage of gem is 0.05kg/m3 the mass loss rate of concrete specimen after 180 dry wet cycles is the smallest (only 0.26%), the relative dynamic modulus of elasticity (95.9%) and the corrosion resistance coefficient of compressive strength (0.919) are the largest. The addition of nano-SiO2 and air entraining agent gem can significantly improve the corrosion resistance of railway concrete in sulfate crystallization environment.