Evaluating the reaction of actual compositions of concrete with respect to alkali-aggregate reactions preliminary testing at 110°C and 150°C

Abstract

Different curing methods at 110°C and 150°C were tested on concrete prisms of various compositions in order to develop a rapid expansion test to evaluate the risl of AAR in actual concrete compositions. While no significant expansion occurred at 110°C (in water or water vapour), we obtained expansion values in the range 0–0.35% for concrete prisms cured at 150°C in water or in alkaline solution during 3–5 weeks. For both curing methods at 150°C, the highest expansion values are obtained for potentially reactive aggregates and high alkali levels in the concrete, whereas the lowest expansions correspond to the concrete mixes containing only non-reactive aggregates or having a total alkali content of less than 2.5 kg m−3. However, alkaline treatment accounts better for the effectiveness of mineral admixtures and, in general, for the reactivity of the concrete compositions, than curing in water. From the correlations obtained with data at 38°C or 60°C and 100% RH after 12 and 4 months, respectively, alkaline curing for 3 weeks at 150°C shows a reasonable potential for predicting accurately the influence of the total alkali content, nature of the aggregates, water/cement ratio and effectiveness of mineral admixtures on concrete expansion.