MICRO-FIBER REINFORCED CEMENT COMPOSITES .2. FLEXURAL RESPONSE AND FRACTURE STUDIES

In Part I of this paper, stress -strain curves for micro-fiber reinfor ced cement-based composites containing high volume fractions of carbon , steel, and polypropylene fibers were obtained. Considerable strength ening, toughening, and stiffening of the host matrix due to micro-fibe r reinforcement under both static and impact conditions were reported. In this paper, composites are characterized under an applied flexural load. Both notched and unnotched specimens were tested in four-point flexure; significant improvements in the flexural behavior due to fibe r reinforcement were noted. Notched specimens were tested to study the growth of cracks in these composites and to develop a valid fracture criterion. With this objective, crack growth resistance curves and cra ck opening resistance curves in terms of the stress intensity factor w ere constructed. The paper recognizes the potential of these composite s in various applications and stresses the need for further research.