Eggshell catalysed rubber aggregates for the sustainable green mortar constructions

Abstract

Sustainability growth in the infrastructure field demands the need for environmentally friendly construction without compromising its structural properties. In this paper, a durable rubberized geopolymer mortar was developed by using the eggshell catalyzation technique. In order to enhance the interfacial bonding of rubber aggregates with the potassium-based geopolymer mortar, the eggshell catalyst was employed as a natural surface modifier. The developed eggshell catalyzed rubber was used to replace 5% by weight of the fine aggregate system and the sustainability of the rubberized geopolymer mortars was studied by assessing the strength and durability characteristics. From the results, it was inferred that the eggshell catalyst transformed the rubber surface into highly hydrophilic and showed a water contact angle of 10°. The trans-esterification process induced by the eggshell-catalyzed rubber aggregates resulted in 10% improved workability and 98.8% recovery in compressive strength of the rubberized geopolymer mortar. Also, due to the formation of secondary gels around the eggshell-catalyzed rubber, the geopolymer mortar becomes denser which prevents the intrusion of foreign ions and showed a 27.9% change in mass under sulphate attack and 33.86 MPa residual compressive strength after 90 days of acid immersion. This attributed the rubberized geopolymer mortar with eggshell catalyzation process to maintain its structural integrity even in the aggressive chemical environment for the feasible applications of deck slab, piers, underground pipe construction, etc.