Improving thermal and mechanic performance of sustainable lightweight concrete facade panels in terms of aggregate type

Abstract

Reducing energy consumption in the production process of lightweight concrete facade panels, utilizing recycled materials, minimizing waste, enhancing strength-to-weight ratio and durability, as well as ensuring ease of service and assembly, play a significant role in sustainability. Previous studies have been conducted to improve the thermal insulation properties of these panels; however, these studies were limited and produced conflicting results regarding sustainability. Additionally, due to a high number of influencing parameters, a definite procedure for determining the optimal mix ratio for lightweight concrete facade panels was not established. This study aims to determine the optimal proportions of coarse/fine aggregates, lightweight aggregates, and recycled aggregates for lightweight facade concrete mixes in terms of weight/strength and thermal insulation performance criteria. The goal is to develop a sustainable lightweight concrete facade panel with sufficient strength for building facades, high insulation capacity, maximal usage of recycled aggregates, while being as low weight as possible. Within the scope of this study, a total of 15 different lightweight concrete mixtures were produced by substituting various ratios of pumice, perlite, and recycled concrete aggregate for fine aggregate in the control mix containing 100% limestone as fine aggregate. The cement content, coarse aggregate amount, coarse/fine aggregate ratio, and slump value were kept constant for all produced mixtures. It was determined that the mixture containing 40% recycled concrete aggregate and 60% pumice as fine aggregate exhibits superior performance in terms of unit volume weight, compressive strength, and thermal conductivity. Within the scope of the study, 15 different lightweight concrete mixtures were produced by substituting various proportions of pumice, perlite, and recycled concrete aggregate in place of fine aggregate in a control mixture containing 100% limestone as fine aggregate. In all produced mixtures, the cement content, coarse aggregate amount, coarse/fine aggregate ratio, and slump value were kept constant. It was determined that the mixture containing 40% recycled concrete aggregate and 60% pumice as fine aggregate exhibited superior performance in terms of unit weight, compressive strength, and thermal conductivity.