New approach to test the sulphate resistance of concrete
A new study examines the tensile strength of concrete exposed to sulphate attack.
The resistance of concrete to sulphate 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 the present research work.
Sodium sulphate solutions at sulfate concentration levels of 3.000 and 6.000 mg SO42−/l were utilized at a temperature of 5 °C to achieve a realistic, yet slightly accelerated attack. The impact of the sulphate solution is studied by measuring the tensile strength and characterizing the ingress of sulfates by XRD and carbon/sulphur analysis.
Strength loss due to sulphate attack
Significant tensile strength loss due to sulphate attack could be observed in the course of time, especially for Portland cement with a high C3A content. The results show a promising new approach to test the sulphate resistance of concrete.
The study is published in: Cement and Concrete Research, Volume 116.
