Role of styrene-based shrinkage reducing agent in polyester resin concrete

Studies on the reduction of setting shrinkage of polyester resin concrete with and without the microfiller CaCO₃ by using a styrene/polysterene shrinkage reducing agent are reported. The setting shrinkage of unmodified polyester resin concrete was quite considerable but could be reduced almost to zero by varying the shrinkage reducing agent content. At high shrinkage reducing agent content, expansion of the sample was observed instead of shrinkage. Some differences in the rate of shrinkage in the initial stages of curing were observed, which provides some insight into the role of the two components of the shrinkage reducing agent in the reduction of shrinkage. Reduction of shrinkage was accompanied by a reduction in compressive strength, which suggests the need for a proper compromise between these two properties for developing polyester resin concretes for specific applications.