表层强化混凝土抗冻耐久性研究

Study on frost resistance durability of surface-strengthened concrete

为研究刷涂强化材料对混凝土抗冻耐久性的影响,选取硅烷和环氧树脂2种强化材料,制备刷涂表层强化材料的混凝土和普通混凝土试件,进行快速冻融循环试验和压汞试验,对冻融循环后混凝土的质量损失、动弹模量衰减、微观结构以及混凝土表层孔隙的变化情况进行分析。研究结果表明:相同冻融循环次数下,表层强化混凝土的动弹模量衰减和质量损失均低于素混凝土,抗冻耐久性显著增强,且硅烷的强化作用强于环氧树脂;硅烷通过表面渗透方式进入混凝土中,在混凝土表面和内部形成致密憎水的网状结构,环氧树脂在试样表面形成了膜状结构层,覆盖孔隙及裂缝。2种强化材料都通过改善混凝土表层孔径分布进而阻碍水分的进入起到提高抗冻耐久性的作用。

In order to study the effects of frost durability of concrete after brushing reinforcing materials,weselected two strengthening materials:silane and epoxy resin,and prepared two kinds of concretes:one of theconcretes brushing surface hardening material,while the other is just ordinary concrete specimen,and then testedtheir freeze-thaw,analyzed the weight loss,dynamic elastic modulus attenuation,variation of concrete pore sizeand the micro structure after conducting freeze-thaw cycles.The test results showed that for the same number offreeze-thaw cycles,the dynamic elastic modulus attenuations and quality loss of the concrete which surface mixedstrengthening materials was lower than that of the plain concrete,while the durability significantly enhanced,andthe strengthening effect of silane is apparent than epoxy resin;when permeating silane into the surface of concrete,the surface and the interior of the concrete formed dense hydrophobic reticular structure;and when permeatingepoxy resin,the surface of sample forms a membrane structure layer,covering the pores and fractures.The two kinds of reinforcement materials both improved the pore size distribution of concrete,so the increase of concretedurability is mainly due to the reduction of water entry.