Experimental and analytical studies on bond strength of geopolymer concrete using pull-out specimens

• Main Authors: Thiyagarajan, Srividya, Ramalakshmi, Kannan Rajkumar Ponnambalam, Jayapaul, Baskara Sundararaj, Murugesan, Jegan, Ramaswamy, Jeyalakshmi
• Format: Conference Proceeding
• Language: English
• Subjects: Bond stress; Bonding strength; Compressive properties; Compressive strength; Concrete; Cubes; Flexural strength; Fly ash; Geopolymers; GGBS; Pull out tests
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0236181

This investigation presents the bond behaviour of the binary system of Fly ash and GGBS geopolymer concrete and deformed steel bars. Pull-out test was carried out on 150 mm concrete cubes with steel bars of diameter 20 and 16 mm. Four air-cured geopolymer concrete mixes of grade M40 comprising of GPC1 (80% fly ash:20% GGBS), GPC2 (70% fly ash:30% GGBS), GPC3 (60% fly ash:40% GGBS) and GPC4 (50% fly ash:50% GGBS) was chosen. Cube compressive strength was found to be increased with GGBS content and strength attainment at 28 days ranging from 44 MPa to 56 MPa at the same curing regime and their corresponding split tensile and flexural strength was determined. As per RILEM recommendations, the pull-out test is conducted and their corresponding bond stress against slip plots is compared with the analytical model using ANSYS. The Steel bar diameter yielded an inverse relation while compressive strength improvement increases the bond strength. The maximum pull-out load and bond stress obtained were: 130 kN and 14 MPa respectively for the Mix GPC4. The experimental ultimate bond stress values of the blended geopolymer concrete were found to be 2-4 times higher than IS standards. Hence, the findings infer that developed FA-GGBS based GPC has improved structural performance.