Degradation rate of natural fiber in cement composites exposed to various accelerated aging environment conditions

•Degradation of sisal fiber in cement exposed to seven aging conditions is studied.•A separate approach to investigate fiber degradation rate directly is proposed.•The sisal fiber suffers a severe degradation in soak conditions at high temperature.•The dynamic wet/dry cycling has a super accelerating effect on fiber’s deterioration.•The mechanism of degradation is alkali hydrolysis of fiber and the mineralization.

This paper reports the influence of different accelerated aging conditions on degradation of sisal fiber in the matrices of cement composites. Seven aggressive conditions, including dynamic wetting and drying cycling and static environments with various temperature and humidity, were studied. The dynamic wetting and drying cycling presented a superior accelerating effect on both the alkali hydrolysis of fiber’s amorphous components and the mineralization of cell wall. The findings indicate that the cyclic changes of humidity at relative high temperature (⩾70 °C) accelerate the degradation of natural fiber in cement matrix more effectively than the static aggressive conditions.