Bond Behavior of Reinforcement in Conventional and Self-Compacting Concrete

Abstract

Self-compacting concrete (SCC) can be placed under its own weight without compaction. In addition, it is cohesive enough to be handled without segregation and bleeding. Modification in the mix design of SCC can have a significant influence on the material's mechanical properties. Therefore, it is important to investigate whether all of the assumptions about conventional concrete (CC) design structures also valid for SCC construction. Bond behavior between concrete and reinforcement is a primary factor in the design of reinforced concrete structures. This study presents a bond strength model based on the experimental results from eight recent investigations of SCC and CC. In addition, the proposed model, code provisions, and empirical equations and experimental results from recent studies on the bond strength of SCC and CC are compared. The comparison is based on the measured bond between reinforcing steel and concrete utilizing the pullout test on the embedded bars at various heights in the mock-up structural elements to assess the top-bar effect on single bars in small prismatic specimens by conducting beam tests. The investigated varying parameters on bond strength are the: steel bar diameter, concrete compressive strength, concrete type, curing age of the concrete, and height of the embedded bar along the formwork.