ABSTRACT
An approach has been developed that has resulted in a significant improvement in the resistance of cellulose fiber reinforced composites to wet-dry cycling. The results of monitoring the mechanical properties of the composites for two years indicate that the reinforcement is stable in the alkaline matrix. The approach has been found to be equally effective whether virgin fibers or fibers derived from recycling newspaper or Kraft papers were used as reinforcement. Keywords: Cellulose fibers, cement, wet-dry cycling, durability
Introduction
Cellulose or wood fibers possess a set of properties that make them unique among the materials that are used as reinforcement in a cementitious system. They are flexible as opposed to rigid glass fibers. Cellulose fibers are inexpensive compared to many other fibers. Recent studies1' 3 have suggested that fibers derived from recycling sources may be effectively used as reinforcement in cement matrices. When dry the cellulose fibers are in the form of flat ribbons (Fig. 1). However, when exposed to moisture, as for instance when placed in a moist cement paste (Fig. 2) they swell and resemble hollow tubes.
