Abstract
A geopolymer is normally considered an environmentally friendly binder due to the utilisation of industrial wastes. This study focusses on the potential of geopolymer preparation at room temperature from landfilled fly ash (LFA) which has been discharged to the land for more than three years. To accelerate the reaction process, 20–30 wt.% LFA was replaced by ground-granulated blast-furnace slag (GGBS). The effect of water glass modulus, Na2O content, water-to-solid ratio, and GGBS content on the setting time and strength development of the binder was discussed. Results showed that to activate LFA, the optimal value of the sodium silicate modulus for alkaline solution was 1.4–1.6 with a Na2O content of 10%, and the water-to-solid ratio was 0.4. In addition, the setting time of the binder reduced with increasing content of GGBS replacement, and the compressive strength increased due to the coexistence of C–(A)–S–H and zeolite-like phases. The maximum compressive strength of the binder was 29.2 MPa after 56 days of curing. The relatively low strength was likely due to the absence of the Q4 unit with a three-dimensional structure.
Highlights
Ordinary Portland cement (OPC) and concrete are considered non-sustainable construction materials due to the high emission of greenhouse gas and large amount of energy consumption during their manufacturing process [1]
This study aims to investigate the potential of preparation of a sustainable landfilled fly ash (LFA)-based geopolymer binder at room temperature
This agreed with the requirement of common Portland cement in GB 175-2007 that the initial setting time should be longer than 45 min, but the final setting time should be shorter than 600 min
Summary
Ordinary Portland cement (OPC) and concrete are considered non-sustainable construction materials due to the high emission of greenhouse gas and large amount of energy consumption during their manufacturing process [1]. It has been reported that industrial cement contributes 7%. Of greenhouse gas emissions and consumes approximately 10% of energy worldwide, annually [2]. One proposed solution is to replace Portland cement in concrete by industrial wastes, such as fly ash. Fly ash is a by-product of coal combustion, mainly produced at power stations. It has fine particles with a size smaller than 75 μm, as it is collected from flue gases by electrostatic precipitators [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
