Influence of a novel hydrophobic agent on freeze–thaw resistance and microstructure of concrete

Abstract

An innovative hydrophobic agent named YREC (Yellow River Engineering Consulting) was adopted in this study. The substrate is mica powder, which is treated with silane coupling agent and polydimethylsiloxane. By comparing hydrophobicity of the hydrophobic agent with different dosages of polydimethylsiloxane and temperatures, the optimum processing scheme of hydrophobic agent was provided. A series of hydrophobic concrete with different water to cement ratios and YREC contents were prepared. Freeze-thaw (F-T) resistance and mechanical properties of concrete were investigated. Meanwhile, microstructure was determined by means of water adsorption test and mercury intrusion porosimetry. The results show that the YREC provides hydrophobic functional group and improves pore network to inhibit the invasion of water, which further enhances the F-T resistance and mechanical properties of concrete significantly. The pore size characterizations indicate that the addition of YREC increases the quantity of transition pores while decreases that of macro-pores, and the mechanical properties of concrete are reduced obviously due to the decrease of macro-pores. Compared with adjusting water to cement ratio, YREC is more conducive to refine pore structure of concrete.