Application of cellulose fibre in ultra-high-performance concrete to mitigate autogenous shrinkage

This study aims to apply cellulose fibre (CF) to reduce the autogenous shrinkage (AS) of ultra-high-performance concrete (UHPC). Different dosages of CF were considered, and the flowability, mechanical properties, hydration heat, AS, and internal relative humidity (IRH) of the UHPC mixtures were tested. The microstructure of UHPC incorporating CF was observed. The results indicated that CF with content higher than 0.3% significantly decreased the flowability of the UHPC mixture. CF can improve mechanical properties of UHPC, while a high CF content in UHPC mixtures increases the porosity of the matrix, thereby adversely affecting the mechanical properties. The addition of CF reduced the maximum heat of the hydration peak and delayed the appearance of the heat of the hydration peak. As the CF content was increased from 0 to 1.1%, the AS was reduced by 36%, and the time for sustaining IRH at 100% was prolonged.