Development and properties of lightweight concrete based on core-shell cold-bonded lightweight aggregate using epoxy resin as interfacial enhancer

Due to the escalating shortage of construction materials and natural aggregate production, the present study aims to produce lightweight concrete (LWC) utilizing a novel artificial core-shell cold-bonded lightweight aggregate (CCLA). The newly developed CCLAs employ an expanded polystyrene (EPS) waste core encapsulated by a cementitious shell, leveraging epoxy resin as interfacial enhancer for reducing EPS exposure ratio from 96.5 % to 0 %. Systematic investigations elucidate the influence of key manufacturing parameters, such as the disc pelletizer's inclination angle, rotation speed, and curing conditions, on the quality of CCLAs. Furthermore, the study explores the use of limestone calcined clay cement, steel slag and ground granulated blast furnace slag as shell materials for optimizing the shell composite with maximal performance. Comprehensive assessments of the resulting CCLA-based LWC (CCLA-LWC) cover fundamental properties, including compressive, splitting, and flexural strengths, alongside a detailed constitutive model under uniaxial compression. Comparisons with existing technologies affirm the superiority of using epoxy resin as an interfacial enhancer for the developed CCLAs, particularly in terms of density, strength, and specific strength. The lightweight aggregate concrete CCLA-LWC developed in this study has the superior comprehensive performance compared to those core-shell lightweight aggregate concretes in existing literature. • Core-shell cold-bonded lightweight aggregate (CCLA) with superior mechanical performances. • Epoxy resin as interfacial enhancer reduces EPS exposure ratio from 96.5 % to 0 %. • Lightweight aggregate concrete (LWC) based on CCLA (CCLA-LWC). • CCLA-LWC achieves 28-day compressive strength of 45.7 MPa.