Effect of particle size and curing temperature on expansion reaction in electric arc furnace oxidizing slag aggregate concrete

This study investigated the effect of particle size and curing temperature on the expansion reaction of concrete to clarify the long-term potential for degradation caused by expansion when electric arc furnace oxidizing slag (EOS) is used as the aggregate. Concrete prism expansion tests were conducted on coarse and fine aggregates of various sizes, during which the aggregates were heat cured at 60 or 100 °C or cured in an autoclave. The results revealed that a low expansion was observed for the coarsest and finest particle sizes, and the highest potential for expansion was observed for medium-sized particles. Heat curing fine aggregates at 100 °C resulted in the highest expansion. However, autoclave curing of coarse aggregates produced the most severe reactions and the highest degradation. If natural aggregate is replaced with EOS, the potential expansion of problematic particles can be identified immediately after the cement is heat cured at temperatures exceeding 100 °C. Thus, careful consideration is required when replacing natural aggregates with EOS.