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.