Comparison of nano-silica-modified manufactured-sand concrete under steam curing and standard curing

Abstract

<p>There are obvious differences in mechanical properties and durability between steam-cured concrete and standard-cured concrete. In this paper, the different properties of nano-silica (NS) modified manufactured sand concrete (NSMC) under standard curing and steam curing were compared. The results showed that the effect of NS on concrete is similar under the two curing methods. The addition of NS can mitigate the loss of later strength and impermeability caused by steam curing. In addition, NS has a synergistic effect with steam curing, and steam-cured concrete with NS shows higher early strength and higher corrosion resistance coefficient. The above phenomena were explained by XRD, SEM, and MIP. The results show that NS under steam curing can further promote the consumption of calcium hydroxide, tricalcium silicate, and dicalcium silicate, as well as the generation of more hydration products to repair the micro-defects caused by steam curing.</p>