Study on honeycombs in structural concrete elements

Abstract

Concrete structures are subjected to various types of surface defects such as honeycombs, surface voids, form streaking, etc. Proper understanding of the root causes of each type of defect is significant in preventing recurrence as well as applying remedies. An extensive field survey was conducted in connection with the construction sector of Sri Lanka to gather information on the current practices. It was found that the construction industry needs more awareness on correct practices. This study attempts to fill the gap between current field practices and standard practices. Poor workmanship in consolidation of fresh concrete leads to most of the defects, but this study shows how the understanding of technical background of each activity and the proper planning at initial stages contribute to effortless improvements in workmanship. Contradictions between codes of practices for design of reinforced concrete and codes of practices for consolidation of concrete were taken into consideration under this study. In order to identify the locations of hidden honeycombs, a series of UPV tests (conventional approach) were performed, quantitative and qualitative analysis of them has been provided under this study. It has shown the importance of moving to modern non-destructive evaluation approaches for such scenarios.