Recycling and Exploitation of Construction and Demolition Wastes as Additives in Unsaturated Polyester Composite Building and Insulation Materials; Mechanical and Thermal Properties Investigation

Abstract

This research investigates the potential of manufacturing composite materials combining good mechanical and thermal insulation characteristics using C&D wastes (Construction and Demolition waste) in substitution of raw aggregates. Unsaturated polyester matrix composites encapsulating C&D waste of 300 μm and 500 μm as additives, at concentrations of 30%, 40% and 50 (% w/w) respectively, were manufactured. The effects of loading these materials with C&D wastes, in terms of mechanical and thermo-insulating performance were studied. Experimental research revealed the strong interrelation between the mechanical performance of materials and parameters such as grain size and concentration of loading agent. In particular, composites encapsulating 300 μm additives demonstrated improved flexural and shear properties, taking values of 34.59 MPa (30% additives), 35.61 MPa (40% additives) and 30.25 MPa (50% additives) for flexural strength and 3.72 MPa (30% additives), 4.18 MPa (40% additives) and 2.66 MPa (50% additives) for shear strength, compared to corresponding 500 μm loaded composites which flexural strength reached  33.58 MPa (30% additives), 34.6 MPa (40% additives) and 27.47 MPa (50% additives). Similarly shear strength reached 2.81 MPa (30% additives), 3.87 MPa (40% additives) and 2.5 MPa (50% additives) respectively. Composite materials loaded at a concentration of 40% (w/w) using 300 μm C&D waste additives, exhibited optimal mechanical efficiency in terms of flexural and shear strength. Thermo-insulating properties of optimum, in terms of mechanical behavior, composite materials were afterwards investigated. Thermal insulation efficiency was determined by measurement of thermal conductivity coefficient (λ) which was calculated at 0.039 W m-1 K-1, lying within the range of values referred in literature for common insulation materials (0.035-0.16 W m-1 K-1). In conclusion, the characteristic attribute of these materials to exhibit adequate mechanical and thermal insulation properties, as validated by the experimental results, indicates their suitability as building and insulation materials in construction applications.