Bond Slip Models for Uncorroded and Corroded Steel Reinforcement in Class-F Fly Ash Geopolymer Concrete

Geopolymer concrete is an innovative construction material that utilizes industrial by-product waste materials to form a cement replacement for concrete manufacture. In order to simulate the behavior of reinforced concrete at all load levels, an understanding of the bond between the reinforcement and the concrete is required. That is, at the serviceability limit state, the bond between the reinforcement and the concrete controls the formation of cracks, crack widening, and tension stiffening. Similarly, adequate bond between the reinforcement and the concrete is required at the ultimate limit state to ensure the full capacity of the reinforcement is obtained. Over time, the bond between the reinforcement and concrete can deteriorate due to corrosion, thus impacting the overall performance of a structure. This paper presents a wide-ranging study of the bond between reinforcement and geopolymer concrete including an investigation of the influence of corrosion. This study involved 102 pull-out test specimens covering a range of parameters including bar diameter, concrete cover-to-diameter ratio, compressive strength, and level of corrosion. Significantly, this study shows that the bond between reinforcement and geopolymer concrete is stronger than that between reinforcement and ordinary portland cement.