Effect of coarse aggregate volume on fracture behavior of self compacting concrete

摘要

This paper presents the effect of volume of coarse aggregate on fracture characteristics of self- compacting concrete (SCC). Based on an experimental programme, a series of three point bending tests were carried out on 58 notched beams. SCC was prepared with coarse aggregate in varying percentages of 30%, 40%, 50% and 60% (as the percentage of the total aggregate volume). For all mixes, the fracture parameters were analyzed by the work-of- fracture method (WFM) and by the size effect method (SEM) to obtain a suitable correlation between these methods which is used to calibrate fracture numerical models. The results showed that with decrease of volume of coarse aggregate from 60% to 30% in SCC, (a): fracture energies of G_f in WFM and G_f in SEM strongly decrease which may be explained by the change in fractal dimensions, (b); based on size effect plot, behavior SCC specimens approaches linear elastic fracture mechanic (LEFM) criterion, (c): SCC ductility, measured by means of characteristic length (L_(ch)) in WFM and fracture process zone length (C_f) in SEM, significantly decreases, (d): the brittleness number is approximately tripled.