Evaluation of the Mechanical Properties and Durability of the Mortar Coating Containing Micro silica and Nano silica

Abstract

Reinforced concrete is vulnerable to corrosion due to chloride attacks. Coating mortars containing pozzolanic materials are available to increase concrete resistance to a corrosive environment. With the utilization of silica in different sizes (micro/nano), more durable concrete can be achieved. The aim of this study is to investigate the mechanical and durability properties of mortars containing micro and nano-silica. In this respect, 0 to 7.5% micro silica and 0 to 5% nano-silica in two different particle sizes were substituted in Portland cement. According to the results, adding micro and nano silica to the concrete mixture enhances the mechanical and durability of the concrete. The optimum mix design consists of 7.5% micro silica with 5% nano-silica of lower fineness. With regard to the nano-silica particle size, lower fineness generally performs better than the higher one due to a greater likelihood of the hydration process developing over time. An increase in shrinkage is the downside of using micro/nano-silica pozzolan. However, no negative influence on concrete durability was observed.