Behaviour of beams made in textile reinforced mineral matrix composites, an experimental study

摘要

In this paper the mechanical behaviour in bending of textile reinforced mineral matrix composite beams is analyzed. Two types of textile reinforcement made in E-glass fibers are considered: unidirectional rov-ings and chopped strand mat (CSM). The mineral matrix is an inorganic phosphate cement (IPC) and presents the advantage to be non-alkaline. The beams are hollow with square cross section, they are realized by bonding together composite plates having the dimensions 200 × 10 × 1 cm. The plates are manufactured by pultrusion process, using the roving and the mineral matrix. In the first part of the paper we present the manufacturing process, and in the successive sections the mechanical characteristics of the composite itself in tension and shear are assessed. During the characterization tests, it has been emphasized that the shear behaviour is the weak point of the composite. Therefore, in order to enhance the mechanical behaviour of the beams, specimens have been strengthened using three types of reinforcement: internal reinforcement with struts, 3D external braiding and continuous wrapping by CSM reinforced mineral matrix. In the second part of the paper, the test in four point bending of four beams is presented. The analysis of the experimental results is governed by the search for a correlation between the phenomena observed at material level and those occurred during the tests of the structural elements.