The effects of surface preparation on the fracture behavior of ECC/concrete repair system

This paper presents the influence of surface preparation on the kink-crack trapping mechanism of engineered cementitious composite (ECC)/concrete repair system. In general, surface preparation of the substrate concrete is considered essential to achieve a durable repair. In this experiment, the "smooth surface" system showed more desirable behavior in the crack pattern and the crack widths than the "rough surface" system. This demonstrates that the smooth surface system is preferable to the rough surface system, from the view point of obtaining durable repair structure. The special phenomenon of kink-crack trapping which prevents the typical failure modes of delamination or spalling in repaired systems is best revealed when the substrate concrete is prepared to have a smooth surface prior to repair. This is in contrast to the standard approach when the substrate concrete is deliberately roughened to create better bonding to the new concrete. (C) 2000 Elsevier Science Ltd. All rights reserved.