Evaluation of metabentonite and metazeolite performance based geopolymers with metakaolin river sand replacement

Abstract

Geopolymer is a long-lasting substance that helps to safeguard the environment and provides an alternative to Portland Cement. By using by-products and using less OPC in this manner, CO2 emissions are also decreased. This field might benefit from a study into the use of various binders in geopolymer manufacturing. Bentonite and zeolite, both naturally occurring and inexpensive, were calcined at 750 °C and employed as binders in this study. Calcined bentonite and zeolite were substituted in five different percentages for each other (20%, 40%, 60%, 80%, and 100% by weight). In addition, the investigation was carried out by substituting river sand for metakaolin (MK) in four different percentages (25%, 50%, 75%, and 90% by weight). At 7, 28, and 56 days, ten geopolymer series were tested for flexural-compressive strength and ultrasonic pulse velocity (UPV). High-temperature test were also applied to geopolymer mortars to examine the impacts following the durability conditions. Variable UPV, weight, and strength findings were discovered in addition to the durability testing. SEM analyses were also used to look at the results of the durability testing. Due to its more excellent Si/Al ratio and more stable zeolitic structure, metazeolite produced better results. The primary products of the alkaline activation process were also studied, with polysialates and zeolites defined in the case of geopolymers and the tobermorite structure defined in the case of calcium-rich materials. Dissolution, condensation, polycondensation, crystallization, and hardness were considered as the key processes of the alkali-activated reaction. The usage of metakaolin enhanced the pozzolanic characteristic by up to 40%, which had a beneficial impact on the findings. When all of the impacts were considered combined, it was discovered that the produced geopolymer samples were resistant to the effects of durability and the sample 50MZ50MB25MK yielded the higher result.