Performance of engineered pulp fibre reinforced composites subjected to weathering conditions

Abstract

An experimental study was conducted to determine the mechanical and durability performance of cementitious composites. Two engineered pulp fibres, which have not been previously used in the production of commercial cementitious materials, and one conventional unmodified fibre, were experimented. Fibre reinforced composites made of these three fibres were subjected to two weathering actions, dry and soak, and freeze and thaw. For each weathering exposure, specimens were subjected to up to 40 cycles. At both exposure conditions, results showed that composites reinforced with engineered pulp fibres had better performance than unmodified pulp fibres in terms of compressive strength, flexural strength, and toughness loss. In addition, microstructural investigation revealed that dry and soak conditions cause the hydration products to penetrate inside the fibre’s lumen, which results in reduced flexural performance. The percent reduction in flexural strength when dry and soak cycles increased from zero to 40, were 49%, and 33%, for composites reinforced with unmodified fibre and engineered fibres, respectively. As well, this study found that freeze and thaw cycles showed a less negative effect on the flexural performance.