Bond strengths between fly ash-based geopolymer or concrete and reinforcing steel

Abstract

This research is part of a study the bonding strength between deformed steel bar and concrete. Several parameters are varied to compare between ordinary Portland cement (OPC) concrete and Class C fly-ash geopolymer concrete (GPC). These concretes are designed to have two different compressive strength, and each of them is cured at 28 days. The diameter of reinforcement is selected  as 12, 16  and 20 mm with deformed type. From the study, it is found that the bond strength increase with increasing the compressive strength, while with decreasing the diameter of reinforcement, as expected. The bond strength of OPC embedded with smaller reinforcement is more sensitive to the increase of the curing time. However, its bond strength is significantly less sensitive to the compressive strength. The bond strength of GPC with higher design compressive strength is more sensitive to the increase of the curing time. However, its bond strength is significantly less sensitive to the diameter of reinforcement.