Uniformity of in situ properties of self-compacting concrete in full-scale structural elements

Inadequate homogeneity of the cast concrete due to poor compaction or segregation may dramatically lower the performance of mature concrete in situ. To ensure adequate compaction and facilitate placement of concrete in structures with congested reinforcement and in restricted areas, self-compacting concrete (SCC) has been developed. Considering the highly flowable and self-levelling nature of the SCC, there are general concerns that segregation and settlement may occur during its transport and placing. This study was designed to provide information on uniformity of in situ properties of SCC mixes in practical structural columns and beams and to compare results with those of properly compacted conventional concrete. The in situ concrete properties were assessed by testing cores for in situ strength, pull-out of pre-embedded inserts and rebound hammer number for near-surface properties. The results indicated that there were not significant differences in uniformity of in situ properties between the SCC mixes and the corresponding well compacted conventional mixes.