LONG TERM PERFORMANCE OF FIBRE REINFORCED CEMENTS AND CONCRETES

An overview of the long term performance of fibre reinforced cement and concretes is presented, covering two main aspects: the performance of composites where the fibres are the main reinforcement, as is the case in thin sheet products, and the performance of fibre reinforced concretes where the fibres serve as secondary reinforcement for crack control. For the first case, the main interest is in the durability of the material itself and the component made of it. Within that context the mechanisms leading to ageing effects are reviewed. They cover chemical processes leading to fibre degradation and physical processes leading to microstructural changes at the fibre-matrix interface, resulting in a variety of effects, some of them opposing in nature: strengthening or weakening of strength and reduction in ductility. The issue of volume stability of thin sheet components is addressed, highlighting the fact that in the component itself these changes in dimensions may be more critical for the long term performance of the composite, and may overshadow influences resulting from aging of the material itself. The concepts and validity of various accelerated tests is discussed in view of these mechanisms. In the case of the use of fibres as secondary reinforcement of concrete, the consequences of crack control on the long term performance of the modified concrete is addressed from the point of view of the influence of the crack control on transport properties, in particular water permeability and chloride ingress.

• INTRODUCTION

• DURABILITY OF FIBRE REINFORCED CEMENT COMPOSITES

• ENHANCEMENT OF LONG TERM PERFORMANCE OF CONCRETES BY FIBRE ADDITION

• CONCLUSIONS

• REFERENCES