The effect of elevated temperature on bond performance of alkali-activated GGBFS paste

Abstract

The main reaction products were investigated by analysis of microstructure of alkali-activated ground granulated blast furnace slag (GGBFS) paste. An experimental research was performed on bond performance of alkali-activated GGBFS paste as a construction adhesive after exposure to 20–500 °C. Through XRD analysis, a few calcium silicate hydrate, hydrotalcite and tetracalcium aluminate hydrate were determined as end products, and they were filled and packed each other at room temperature. In addition, akermanite dramatically increased at 800 °C and above. The two key parameters, the ultimate load P _u.T and effective bond length L _e, were determined using test data of carbon fiber-reinforced polymer (CFRP)-to-concrete bonded joints at elevated temperature. The experimental results indicate that the ultimate load P _u.T remains relatively stable initially and then decreases with increasing temperature. The effective bond length L _e increases with increasing temperature except at 300 °C. The proposed temperature-dependent effective bond length formula is shown to closely represent the test data.

Keywords

alkali-activated GGBFS paste / microstructure / bond / effective bond length / elevated temperature

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