Experimental Investigation of the Relationship between Dynamic Characteristics and Mechanical Properties of Fly Ash-Based Geopolymer Reinforced Concrete Beams

This manuscript presents an experimental investigation of fly ash-based geopolymer-reinforced concrete beams' dynamic characteristics and mechanical properties. The purpose of this study is to compare the performance of geopolymer and portland cement concrete in terms of the viscous damping ratio, resonance frequency, compressive strength, and modulus of elasticity. The scope of the effort includes fabricating 14 reinforced concrete beams, 12 of which were made with geopolymer concrete and 2 with portland cement concrete. In this study, the experimental modal analysis method was employed. Test beams were placed on polyurethane cube supports to achieve free-free mode or oscillation conditions. For data analysis, 44 equally spaced analysis points were determined on the beams. Some of these points were stimulated five times along the x-x axis using a modal hammer to obtain FRF and viscous damping ratio graphs. As a result, the resonance frequency of portland cement concrete was higher than that of geopolymer concretes, while the viscous damping rate was lower. Furthermore, it was determined that the modulus of elasticity changed inversely with the viscous damping ratio rather than the compressive strength when examining the relationship between modal parameters and mechanical properties. These findings have significant implications for using geopolymer concrete in construction, as it can help distribute loads homogeneously and increase the durability of structures. Overall, this study provides valuable insights into the relationship between dynamic characteristics and mechanical properties of geopolymer and portland cement concrete, informing the development of more sustainable and resilient construction materials.