1996 Volume 7 Issue 2 Pages 79-89
The tensile behaviour of cement composites reinforced with two different kinds of continuous fibre is experimentally investigated, and a mathematical model is proposed to explain this tensile behaviour. The proposed mathematical model, which is derived from frictional bond stress transfer between fibres and the matrix, gives reasonable agreement with the experimental results. This theoretical model demonstrates the followings : (i) The stress strain curves in the multiple cracking region consists of two regions depending on the stress transfer length of the two different fibres. (ii) The gradient of the stress-strain curve in the postcracking region can be represented as the sum of EfVf for each reinforcing fibres. (iii) When one fibre breaks upon reaching the ultimate strain in the post-cracking region, the stress supported by the fibre is redistributed to the remaining fibres. If these fibres can handle the extra force resulting from the stress redistribution, the composite will deform further and support the load. It is shown that the characteristics of the fibres and the volume fraction need to be properly combined in order to obtain high strength and high ductility. The proposed model will be useful in the design of the high-performance cement composites.
