Assessment of glass fibre reinforced cement by in-situ SEM bending test

The purpose, development and the first results of a new test method, an SEM in-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 ap paratus enabling microfracture processes in bending to be simultaneously sc anned and the corresponding load/deflection and other data and parameters a ccurately recorded. The new test facility provides an opportunity to obtain new quantitative and qualitative data considerably more relevant to the fr acture processes concerned than those obtained when previous SEM in-situ te sts are used. It is now possible to examine specimens of a more realistic s ize and including different types of reinforcement in bending, a very commo n and practical mode of loading. The new test method has been initially app lied to an investigation of fracture mechanism in glass fibre reinforced ce ment (GRC) where the results have shown major differences between flexural performance of aged and unaged GRC. The in-situ SEM flexural test offers an effective new tool for the investigation of the complex micro-fracture mec hanics of fibre reinforced composites as represented by cement reinforced w ith bundles of glass fibres.