Effect of low modulus sisal and polypropylene fibre on the free and restrained shrinkage of mortars at early age

摘要

This is the first part of a two-part paper involvingthe study of the plastic shrinkage and cracking sensitivity duringearly drying of mortars reinforced with low modulus sisal,coconut, and polypropylene fibres. This work also evaluates theeffectiveness of crack control at early ages on the corrosion ofsteel bars, which are sensitive to the presence of crack in the matrix.The performance of cement-based material in the fresh state isexpected to improve by reducing the free shrinkage and sensitivityto cracking due to the addition of a low content of polypropylenefibres. This paper discusses the effectiveness of the use of naturalsisal fibres for controlling the free and restrained early ageshrinkage of mortars and compares their performance with that ofpolypropylene fibre. In addition, a prediction model for the freeplastic shrinkage of natural sisal fibre reinforced mortars isproposed based on a factorial design of experiment.