Influence of elevated temperature exposure on the interfacial shear strength capacity of binary blended high strength self-compacting geopolymer concrete

Abstract

The development of sustainable infrastructure is a serious issue faced by modern society. Portland cement is one of the common ingredients in concrete, which influences construction activities. The major issue with the employment of cement in civil-based works is that it is responsible for carbon dioxide emission (CO2-e), the primary greenhouse gas responsible for global warming. Alternative to cement-based concrete, geopolymer concrete (GPC) employs zero cement for concrete production, leading to a reduction in CO2-e. In the case of mass concreting, interface/joints are developed, which are found to be the possible failure spots of brittle fracture. Concrete with different grades (strength) may interface, or other building materials, such as reinforcing materials. The interfacial bond strength has to be examined to ensure the homogeneity of the composite structures. The employment of shear ties at the interface ensures homogeneous behaviour. Moreover, a higher number of shear ties in the shear zone increases the cost of production. The interfacial shear strength (ISS) parameters will be miserably damaged in the concrete structures subjected to fire accidents, which might depend on the intensity of temperature exposure and its duration. The current study investigates the ISS of the High Strength Self-compacting geopolymer concrete (HSGC) in the interface of push-off samples. SCGC was made using binary blended composites, which comprised Fly Ash (FA), Metakaolin (MK), and Ground Granulated Blast Furnace Slag (GGBFS) as precursor materials. The work highlights the need to comprehend the reduction in shear strength of SCGC subjected to high temperatures. The fresh properties of the SCGC composites strictly adhered to the EFNARC guidelines. The SCGC composites, after their curing period, were exposed to 821 ℃, 925 ℃, 986 ℃, and 1029 ℃ following ISO 834 guidelines. Residual mechanical properties were examined after being cooled to room temperature.