Mechanical and Thermal Insulation Properties of rGFRP Fiber-Reinforced Lightweight Fly-Ash-Slag-Based Geopolymer Mortar

Abstract

As a lightweight cementitious material for thermal insulation, the mechanical performance of foamed geopolymer is always compromised by its density reduction. In this study, recycled-glass-fiber-reinforced plastic (rGFRP) fiber was used to reinforce the fly ash-slag based foamed geopolymer, and vitrified micro bubbles (VMB) were applied to further decrease the thermal conductivity and modify the resistance of the lightweight mortar against drying shrinkage. The results revealed that the density, compressive strength, and thermal conductivity of the foamed geopolymer with/without VMB decreased with the increase in foaming agent content. By adding 2~6% of rGFRP fiber, the compressive strength was increased by 25~165%, and the drying shrinkage was reduced the most, by 55%. After the addition of 10% of VMB, the density, thermal conductivity, and drying shrinkage of foamed geopolymer mortar were further decreased, with the highest reductions of 8%, 26%, and 64%, respectively, due to the reduced pore volume and increase proportion of closed pores. With 6% of rGFRP fiber and 25% of foaming agent, the lightweight geopolymer mortar had the optimum performance, with compressive strength of 1.343 MPa, thermal conductivity of 0.134 W/(m·K), and drying shrinkage of 0.095%. This study developed a sustainable lightweight mortar with multiple types of industrial by-products, which benefit both the development of thermal insulation materials and reuse of solid wastes.

Ensuring the Energy Efficiency of Buildings through the Simulation of Structural, Organizational, and Technological Solutions for Facade Insulation

“…Some works aim to compare the thermal performance of a polylactic acid 3D-printed block with an internal honeycomb structure whose air cavities are filled with natural and recyclable waste-insulating materials [6] and expanded vermiculite [7]. Lightweight mortar with foamed geopolymer reinforced by recycled-glass-fiber-reinforced plastic fiber is used to decrease shrinkage and increase thermal productivity [8]. Vacuum insulation panels with fibrous porous material provide significant adiabatic performance for heat/cooling systems to reduce energy consumption [9].…”