Assessment of glass fibre reinforced cement byin-situ SEM bending test

Abstract

The purpose, development and the first results of a new test method, an SEMin-situ 3-point flexural test are presented. A large SEM chamber housing a eucentric tensile testing rig has been redesigned and fitted with a new apparatus enabling microfracture processes in bending to be simultaneously scanned and the corresponding load/deflection and other data and parameters accurately recorded. The new test facility provides an opportunity to obtain new quantitative and qualitative data considerably more relevant to the fracture processes concerned than those obtained when previous SEMin-situ tests are used. It is now possible to examine specimens of a more realistic size and including different types of reinforcement in bending, a very common and practical mode of loading. The new test method has been initially applied to an investigation of fracture mechanism in glass fibre reinforced cement (GRC) where the results have shown major differences between flexural performance of aged and unaged GRC. Thein-situ SEM flexural test offers an effective new tool for the investigation of the complex micro-fracture mechanics of fibre reinforced composites as represented by cement reinforced with bundles of glass fibres.