Influence of Steel Fibers on the Interfacial Shear Strength of Ternary Blend Geopolymer Concrete Composite

Sustainable development is a major issue confronting society today. Cement, a major constituent of concrete, is a key component of any infrastructure development. The major drawback of cement production is that it involves the emission of CO2, the predominant greenhouse gas causing global warming. The development of geopolymers has resulted in a decrease in cement production, as well as a reduction in CO2 emissions. During mass concrete production in the construction of very large structures, interfaces/joints are formed, which are potential failure sites of crack formation. Concrete may interface with other concrete of different strengths, or other construction materials, such as steel. To ensure the monolithic behavior of composite concrete structures, bond strength at the interface should be established. The monolithic behavior can be ensured by the usage of shear ties across the interface. However, an increase in the number of shear ties at the interface may reduce the construction efficiency. The present study aims to determine the interfacial shear strength of geopolymer concrete as a substrate, and high-strength concrete as an overlay, by adding 0.50%, 0.75%, and 1% crimped steel fibers, and two and three shear ties, at the interface of push-off specimens. It was found that three shear ties at the interface can be replaced by two shear ties and 0.75% crimped steel fibers. In addition, a method was proposed to predict the interface shear strength of the concrete composite, which was found to be comparable to the test results.