Sulfate resistance of alkali-activated slag and Portland cement based reactive powder concrete

Abstract

This paper investigates the sulfate resistance of conventional Portland cement-based and alkali-activated slag-based reactive powder concretes (CRPC and ARPC). CRPC and ARPC mixtures were subjected to 10% sodium sulfate and magnesium sulfate solutions for 6 months. The influence of sulfate exposure was assessed by monitoring the expansions, mechanical and microstructural properties of RPC mixtures during the exposure time. Both RPC mixtures showed superior sodium sulfate resistance with very low mechanical strength losses and expansions. Magnesium sulfate was found more detrimental for both mixtures as compared to sodium sulfate. ARPC performed better than CRPC in magnesium sulfate solution in terms of strength and toughness losses, and visual deterioration. The superior performance of ARPC against sulfate attacks may be attributed to the absence of Ca(OH) 2 and the substitution of aluminum to C-S-H structure. • Sulfate attack on alkali activated slag - and Portland cement based - RPC (ARPC and CRPC) was investigated. • Strength losses of RPCs were very low compared to normal and high strength concrete. • ARPC and CRPC exhibited a very good resistance to sodium sulfate attack. • ARPC showed higher resistance to magnesium sulfate attack than CRPC.