Tensile strength of concrete exposed to sulfate attack.

Abstract The resistance of concrete to sulfate attack is often analyzed using laboratory test methods on mortar samples and expansion measurements. In rare cases the loss of strength is measured by bending or tensile strength tests. To reduce the effort of sample preparation for tensile strength testing, briquet specimens according to ASTM C307 were used in this research work. Sodium sulfate solutions at sulfate concentration levels of 3.000 and 6.000 mg SO 4 2−/l were utilized at a temperature of 5 °C to achieve a realistic, yet slightly accelerated attack. The impact of the sulfate solution is studied by measuring the tensile strength and characterizing the ingress of sulfates by XRD and carbon/sulfur analysis. Significant tensile strength loss due to sulfate attack could be observed in the course of time, especially for Portland cement with a high C 3 A content. The results show a promising new approach to test the sulfate resistance of concrete. [ABSTRACT FROM AUTHOR]