Experimental Investigation on Mechanical and Durability Properties of M60 Grade High-Performance Fly Ash-Based Geopolymer Concrete
Abstract
Ordinary Portland cement (OPC) production is energy intensive and emits significant amount of carbon dioxide, thus the need for sustainable alternatives in the construction industry. This study experimentally examines the mechanical properties and durability of the high-performance geopolymer concrete (HPGPC) with 100% Class F fly ash as the sole binder. Sodium hydroxide and sodium silicate solutions were used for activation of the geopolymer binder and the geopolymer specimens were oven cured at 80°C for 48 h. OPC concrete was prepared with conventional M60 grade mix proportion and water cured as a control sample for comparison. The mechanical properties evaluated were compressive strength at 7, 14, 28, 56 and 90 days and split tensile strength at 7, 14 and 28 days. Durability was tested by rapid chloride permeability test (RCPT), 5% sulphuric acid attack test and water permeability. The geopolymer concrete at 28 days showed a compressive strength of 68.58 MPa which is equal to the conventional concrete of 69.18 MPa, and a split tensile strength of 4.83 MPa was also achieved, which is equal to the conventional concrete of 5.08 MPa. The geopolymer concrete also had excellent durability, with a charge passed of 319 coulombs compared with 578 coulombs for conventional concrete. The geopolymer concrete exhibited lower weight and strength loss under acid exposure of 2.02% and 14.4%, respectively, after 90 days of exposure, while the OPC concrete exhibited weight and strength loss of 6.19% and 26.8%, respectively, after 90 days of exposure. Also, the penetration depth of water has decreased from 14.5 mm to 11.2 mm. The outcome shows that the mechanical properties of this 100% fly ash based HPGPC are also approximately equal to OPC-based test sample and the durability is better, suggesting that this material has potential as a sustainable material for high-performance structural applications.