Assessing the risk of ASR in LC3 binders based on low-grade calcined clay

Abstract

The research investigates the impact of limestone calcined clay cement (LC3) on the mechanical properties and durability of cement-based materials in the context of alkali-silica reactions (ASR) for sustainable construction. Comparative experiments were conducted on binary and ternary blends of low-grade kaolinitic calcined clays and conventional supplementary cementitious materials (SCMs). Two distinct low-grade kaolinitic clays were calcined, and blends with Portland cement, ground-granulated blast-furnace slag (GGBFS), and silica fume (SF) were prepared for comparative analysis. Results reveal that replacing 30 wt% of Portland cement with these calcined clay blends substantially reduces expansion in mortar and concrete during accelerated and long-term tests, altering micropore structure. These blends demonstrate superior performance compared to other studied SCMs. Despite a slight decrease in compressive strength compared to the control mixture, there is a noteworthy improvement in permeability and resistance against expansion. Also, in the early stages of ASR, an improvement in concrete's mechanical properties and durability is observed, attributed to the ASR gel filling the pores.