ABSTRACT

The adhesional and frictional bonding between a fibre and cementitious matrix are relatively weak. They have however significant contribution and practical significance in the case of composites having high surface area fibres (e.g. thin man-made synthetic filaments such as carbon, referred to sometimes as microfibres, with diameters in the range of 10 J.Lm), and advanced cementitious matrices which are characterized by an extremely refined microstructure and very low porosity (i.e. water/binder ratios lower than about 0.3). In conventional fibre reinforced concretes, where the matrix water/binder ratio is 0.40 and above, and the fibres are of a diameter in the range of 0.1 mm or bigger, efficient reinforcement cannot be induced by adhesional and frictional bonding, and mechanical anchoring is required. For this purpose a variety of fibre shapes have been developed and are used commercially.