DURABILITY OF CEMENT SHEETS REINFORCED WITH FIBRILLATED POLYPROPYLENE NETWORKS - 10 YEAR RESULTS

Cement sheets reinforced with layers of networks of fibrillated polypropylene film have been exposed to natural weathering, underwater storage and storage in laboratory air for periods up to 10 years. The effect of these exposure conditions on the stress-strain performance of the composite in uniaxial tension is described, and different characteristics are apparent for each exposure condition. The bond strength between film and cement has been shown to be independent of time and storage condition, and the film strength also shows little change with time. Important considerations from the potential user's point of view are that 10 years of freezing and thawing under UK winter conditions have not significantly affected the composite as measured by the initial elastic modulus, and the material has remained ductile with a failure strain in excess of 5% after 10 years underwater.