Modified pull-off test evaluation of bond properties in preplaced aggregate concrete incorporating silica fume

Abstract

In this study, an experimental investigation was conducted to examine the bond strength of preplaced aggregate concrete (PAC) using a modified pull-off test that avoids the necessity for coring. The PAC was produced using 10 mm and 20 mm coarse aggregates and cement grout with and without the addition of silica fume (SF). Further, the bond strength of conventional concrete was examined to draw a comparison to PAC. The results demonstrate that although the compressive strength of PAC improved by around 20 % with the reduction in coarse aggregate size, the bond strength of PAC decreased by around 49 %. However, with the incorporation of SF, the bond strength improved by nearly 57 %, irrespective of the size of the coarse aggregate used. For the conventional concrete and PAC samples exhibiting similar compressive strength, the bond strength of the PAC was significantly lower than that of conventional concrete.