Files
Abstract
Geopolymer cement is an alternative binder manufactured from fly ashes that can fully replace portland cement in traditional reinforced concrete applications. As a viable material for precast components, geopolymer features very rapid strength development and the ability to be prepared using typical concrete equipment. This study focused on a sensitivity analysis of three base mixture designs of geopolymer cement concrete (GCC) with compressive strengths ranging from 1500-6000 psi (10.3-414 MPa). The fresh concrete properties including slump flow, air content, and temperature were measured and correlated to the mechanical properties including the compressive strength, modulus of rupture, and modulus of elasticity. The main purpose of the sensitivity analysis is to determine the level of influence of typical production variables on the resulting mechanical properties of the concrete. The production variables, such as, water to cementitious materials ratio (w/cm), curing temperature, and curing duration are each known to impact the compressive strength and elastic properties of GCC. Regression analysis was used to determine the level of influence of each production variable on mechanical properties. The interactions between changes in the production variables were also studied to determine if a combination of variables may have a greater net impact on the mechanical properties of the concrete. From the analysis, we find that as we adjust production variables we can influence the resulting compressive strength. These relationships have been illustrated with the regression models. This study also characterized the freeze thaw durability of GCC. The study resulted in improved freeze-thaw durability of GCC for a 2% to 3% air content range compared to the same range in portland cement concrete (PCC).