Tensile characterisation of thick sections of Engineered Cement Composite (ECC) materials

Abstract

Engineered Cement Composite (ECC) materials have the potential to be used in applications where a level of pseudo-ductility under tensile stress is required. Most previous work has focussed on comparatively thin specimens. For future civil engineering applications, however, it is imperative that the behaviour of thicker specimens is understood. In the present work, specimens containing cement powder, water, polymeric fibres and admixtures were manufactured following two different processes and tested in tension. Multiple matrix cracking was observed during tensile testing, leading to a pseudo-ductile behaviour. Complementary measurements of sample density and porosity suggest that a high porosity could be linked with an enhanced tensile strain-to-failure whereas high density is associated with a high maximum stress. The fibre dispersion, assessed by scanning electron microscopy, indicated that mechanical performance was enhanced with increasing proportion of fibres aligned along the tensile test axis, and this orientation can be linked to the manufacturing process.