Paper number 267

SIZE EFFECTS ON PLAIN AND FIBER REINFORCED CONCRETES AT HIGH LOADING RATES

Sidney Mindess¹ and Klaus-Alexander Rieder²

1Department of Civil Engineering, University of British Columbia
2324 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
2W.R. Grace & Co.-Conn., CC&MP Laboratory
62 Whittemore Avenue, Cambridge, Massachusetts 02140, U.S.A.

Summary

This study was carried out to evaluate the size dependence of the maximum stress and the fracture energy of fibre reinforced concrete under impact. Impact tests were carried out using a large instrumented drop-weight impact machine. The impact loads were applied as line loads along the centre lines of the top and bottom faces of concrete cubes, thereby inducing a state of splitting tension. The tests were performed at different drop heights (i.e., loading rates) to investigate the influence of the loading rate on the size effect. The concrete cubes, ranging in size from 101.6mm to 406.4mm, contained discontinuous fibers of either steel or polypropylene. It was found that the fracture energy increased considerably as both size and loading rate were increased; the effects on strength were slight.

Keywords

concrete, impact, size effect, steel fibres, polypropylene fibres, splitting tension, strength, fracture energy.