Nitrate corrosion resistance of concrete with nanoparticles under dry–wet cycles

Abstract

Abstract The concrete of harbor wharf is in the environment of multifactor erosion. Under the coupled effects of dry–wet cycles and nitrate erosion, the durability of marine concrete gradually decreases. Therefore, it is an important issue to improve the durability of concrete. The changes of concrete durability are investigated under the coupled effects of dry–wet cycles and nitrate erosion, and the concrete durability are improved by adding nanoparticles. Nano‐concretes are made by adding different amounts of nano‐SiO 2 and nano‐Al 2 O 3 to plain concrete. The relative dynamic elastic modulus of nano‐concretes and the NO 3 − content are measured as indicators to evaluate the durability of nano‐concretes. The microstructure of nano‐concretes is analyzed through scanning electron microsope (SEM) and energy dispersive spectrometer (EDS）. The test results show that relative dynamic elastic modulus of nano‐concretes is increased obviously, and NO 3 − content of nano‐concrete at different depths is lower than that of plain concrete under the same number of dry–wet cycles. NO 3 − content of nano‐concrete is lower than that of plain concrete. Nanoparticles can optimize the pore structure of concrete and generate more C‐S‐H gels. Therefore, concrete durability can be efficiently increased through adding nano‐SiO 2 and nano‐Al 2 O 3 under the coupled effects of dry–wet cycles and nitrate erosion.