Study of Self Compacting Geopolymer Concrete (SCGC) haunch beams at monotonic loading and loading-unloading scheme

Abstract

Numerous reinforced concrete structures require strengthening due to mistakes in detail engineering design, incorrect execution during construction, or overloading. One method of structural strengthening is to use haunch beam casted near column. The development of infrastructure in Indonesia leads to an increase in cement use. This phenomenon causes a greenhouse effect due to higher CO2 emissions, so that an effort is performed in order to reduce the use of cement concrete by using geopolymer concrete. This study aims to experimentally analyze the behavior of haunch beams using both Self-Compacting Geopolymer Concrete (SCGC) and conventional Self-Compacting Concrete (SCC) in terms of load and deflection at first crack, yield, and ultimate conditions as well as crack pattern and plastic hinge of the beam. This study utilized four specimens consisting of SCGC and SCC haunch beams with a compressive strength fc’ of 31 MPa. All identical specimens were tested at monotonic loading and loading-unloading conditions. As a result, the haunch beams due to monotonic loading have larger load capacity and deflection compared to the haunch beams due to loading-unloading. The SCGC haunch beam has slightly lower load capacity and smaller deflection compared to the SCC haunch beam. This shows the SCGC performance is relatively similar to that of the SCC. The SCGC can substitute the SCC, especially for structural reinforcements. Due to monotonic loading and loading-unloading state, both the SCGC and the SCC haunch beams were plasticized at the same location at the haunch end. By implementing the haunch beams, plastic hinges move away from the column.