Mechanical and Microstructure Analysis Results

Lujain Salem, University of Louisville
Young Hoon Kim, University of Louisville

Description

Fly Ash-based Geopolymer: Microstructure and Compressive Strength Authors Ms. Lujain Salem - United States - University of Louisville Dr. Young Hoon Kim - United States - University of Louisville Abstract Geopolymer is an emerging alternative binder to Portland cement-based concrete. The main ingredients for geopolymer require high concentrations of alumina and silica in precursors, such as fly ash. Geopolymerization is a chemical process to form a three-dimensional, polymer-like network by reacting alumina and silica-rich materials with an alkaline activator. Oxide Calcium Oxide (CaO) content in fly ash has been recognized as an important factor in classifying fly ash types in Portland concrete based on the hydration process. However, CaO content plays a different role in geopolymerization, where it competes with the hydration process. Bothworkability and hardened properties are affected significantly. This is because water is still used in geopolymer concrete mix design, even though it acts as a catalyst in geopolymerization. Therefore, a better understanding of the impact of CaO content in fly ash on geopolymerization is needed to effectively utilize diverse fly ashes from coal plants. This study investigates how the CaO content affect the geopolymer properties by changing water content and curing temperature. Fly-ash based geopolymer mix design includes water-to-binder (W/B) ratios of 0.4 and 0.5 and curing temperatures (25, 60, 75, 100, 120 deg C), utilizing fly ash with relatively-high contents of CaO content from local power plant in Kentucky. Compressive strength, X-Ray diffraction analysis (XRD), Fourier transform infrared (FTIR), and scanning electron microscope (SEM) analyses were employed to assess the as-received fly ash. Test results and analysis reveal the impact of water content and curing temperature on compressive strength and microstructure, the final results and impacts of CaO content in geopolymerization will be discussed in the final paper along with the previous studies. The sensitivity analysis will be performed to understand the effect of CaO concent in geopolymerization within the same classification of fly ash (Class F).

 
May 14th, 3:30 PM May 14th, 5:00 PM

Mechanical and Microstructure Analysis Results

Grand Rapids, Michigan

Fly Ash-based Geopolymer: Microstructure and Compressive Strength Authors Ms. Lujain Salem - United States - University of Louisville Dr. Young Hoon Kim - United States - University of Louisville Abstract Geopolymer is an emerging alternative binder to Portland cement-based concrete. The main ingredients for geopolymer require high concentrations of alumina and silica in precursors, such as fly ash. Geopolymerization is a chemical process to form a three-dimensional, polymer-like network by reacting alumina and silica-rich materials with an alkaline activator. Oxide Calcium Oxide (CaO) content in fly ash has been recognized as an important factor in classifying fly ash types in Portland concrete based on the hydration process. However, CaO content plays a different role in geopolymerization, where it competes with the hydration process. Bothworkability and hardened properties are affected significantly. This is because water is still used in geopolymer concrete mix design, even though it acts as a catalyst in geopolymerization. Therefore, a better understanding of the impact of CaO content in fly ash on geopolymerization is needed to effectively utilize diverse fly ashes from coal plants. This study investigates how the CaO content affect the geopolymer properties by changing water content and curing temperature. Fly-ash based geopolymer mix design includes water-to-binder (W/B) ratios of 0.4 and 0.5 and curing temperatures (25, 60, 75, 100, 120 deg C), utilizing fly ash with relatively-high contents of CaO content from local power plant in Kentucky. Compressive strength, X-Ray diffraction analysis (XRD), Fourier transform infrared (FTIR), and scanning electron microscope (SEM) analyses were employed to assess the as-received fly ash. Test results and analysis reveal the impact of water content and curing temperature on compressive strength and microstructure, the final results and impacts of CaO content in geopolymerization will be discussed in the final paper along with the previous studies. The sensitivity analysis will be performed to understand the effect of CaO concent in geopolymerization within the same classification of fly ash (Class F).