Experimental and Numerical Analysis of the Fire Resistance of Reinforced Geopolymer Concrete Beams

Geopolymer concrete is a green building material, and related research has been focused on the material level, with relatively few experimental studies conducted at the structural component level. In this paper, full-size reinforced geopolymer concrete beams were designed for fire testing and residual load tests after the fire. The influence of the initial crack width on the beams’ fire resistance performance was compared. The research results indicate that geopolymer concrete beams exhibit excellent fire resistance without experiencing bursting or spalling during a fire. After being exposed to fire, the reinforced geopolymer concrete beams maintain their load-bearing capacity well. Beams with an initial crack width of 2.3 mm reach the serviceability limit state under faster time and smaller load conditions. Following this, a thermomechanical coupled finite element model was developed and validated. Through extensive parametric studies, the reinforcement ratio and fire duration were found to be significant factors affecting the residual load-bearing capacity of geopolymer concrete beams after exposure to fire. Finally, a method for calculating the residual bearing capacity of reinforced geopolymer concrete beams after fire was proposed.