The effect of alkali–silica reaction on steel fiber–matrix bond characteristics of cement based mortars

The effect of ASR on fiber–matrix bond behavior has been investigated in this research. The potentially reactive basaltic aggregate was chosen as a reactive material. Two series of specimens containing different amounts of supplementary cementing materials (SCMs) were prepared. One of them was cured in 1 M NaOH solution at 80 °C, other series were cured in 80 °C water up to 150 days to obtain similar maturity. ASR expansion, single fiber pull-out load, debonding toughness, flexural and compressive strength was determined. Test results indicate that the ASR gel congestion in fiber–matrix interface increased the bond strength significantly during alkali exposure. Furthermore, SCMs are effective to reduce ASR expansion and to prevent the mechanical properties loss due to ASR. Micro-structural investigations revealed the reaction products having different morphology (fibrous, rosette type, network appearance, etc.) in alkali exposed specimens.