Concrete for long-time service in sulfate environment

Abstract Data on concretes soaked continuously in a 2.1 percent sodium sulfate solution and alternately soaked and dried served for predicting service life. Sixteen out of 19 concretes made with Type V and II cements showed life expectancies of less than 50 years. Concretes containing different pozzolans showed a spectrum of effects ranging from deleterious to highly beneficial. Only 6 out of 33 pozzolan concretes had life expectancies of less than 50 years. Fly ash, pumice, and two calcined products markedly improved sulfate resistance. Seven of 11 concretes having a life expectancy in excess of 100 years, some possibly up to 200 years, contained fly ash. Revision of present day specifications for sulfate resisting concrete is recommended.