Chemical resistance of nano silica added concrete

Abstract

This study investigated the effects of nano silica on acid and sulphate resistance of concrete. The changes in mass and compressive strength of the concrete specimens for different immersion periods were determined. It was observed that, M 30 grade concrete produced with 0 %, 1 %, 2 %, 3 % nano silica have shown mass loss of 11.24 %, 9.01 %, 5.10 % and 3.59 % respectively at 56 days of immersion in acid solution. M 40 grade concrete produced with 0 %, 1 %, 2 %, 3 % nano silica have shown mass loss of 9.36 %, 8.71 %, 4.98 % and 3.56 % respectively at 56 days of immersion in acid solution. M 30 grade concrete produced with 0 %, 1 %, 2 %, 3 % nano silica have shown mass loss of 2 %, 1.55 %, 1.26 % and 0.91 % respectively at 56 days of immersion in sulphate solution. M 40 grade concrete produced with 0 %, 1 %, 2 %, 3 % nano silica have shown mass loss of 1.63 %, 0.82 %, 0.43 % and 0.29 % respectively at 56 days of immersion in sulphate solution. Similarly, the reduction in compressive strength after immersion in acid and sulphate solution was observed with the addition of nano silica. Among the two chemical environments, sulfuric acid was found to be most dangerous for all concrete mixes. Concrete mixes produced with nano silica showed superior durability.