Pull out behaviour of macro synthetic fibres: effects of fibre type, matrix strength and microcracking

BOSSIO, M.E.; TORRIJOS, M.C.; ZERBINO, R.; GIACCIO, G.

Brescia

Simposio; Fourth International Symposium Bond in concrete; 2012

Fibre incorporation in concrete control crack propagation and enhance the mechanical properties, improving fatigue and impact performance. Steel fibres have been used along decades and more recently synthetic macrofibres have been developed, with an increasing interest in their application. The fibre-matrix bond strength has been widely studied in the case of steel fibres but the bond response of synthetic fibres still needs to be explored, mainly considering the different types that are now available. This paper studies the fibre-matrix bond strength by means of pull-out tests. Specimens were composed by a unique fibre into a mortar matrix. Six types of synthetic macrofibres and two hooked-end steel fibres, conventional and high-strength mortars were used. Pull-out tests were performed at different ages between 14 and 90 days. In addition, to analyze the bond strength in damaged matrices, oven dried specimens and mortars with alkali silica reactions were included.