Applied development of sustainable-durable high-performance lightweight concrete: Toward low carbon footprint, durability, and energy saving

Abstract

Over the past few decades, the utilization of Lightweight Concrete (LWC) has emerged as a promising solution for reducing the dead load of structures. However, a key concern associated with the reduction of concrete density, is the potential decrease in mechanical and durability properties. This paradox necessitates a precise mix design that fulfills the requirements of high-strength concrete. This article investigates the influence of Lightweight Expanded Clay Aggregate (LECA) on the strength and durability, and thermal conductivity of Lightweight High-Performance Concrete (LWHPC). The LWHPC mixes explored in this study include sustainable cement solutions such as Portland limestone cement, varying water/binder ratios of 0.3 and 0.35, Leca contents ranging from 5 % to 20 % by volume, and two different pozzolanic supplements, namely silica fume and fly ash, which can be reducing porosity and enhancing durability and mechanical strength. The durability properties of the concrete were assessed through water absorption, electrical resistivity, and chloride migration profiles. Additionally, thermal conductivity measurements were conducted on all specimens. The results indicate that LWHPC, with a lower water/binder ratio, exhibits higher compressive strength and lower absorption, indicating good concrete quality. Generally, after a curing period of 90 days, mixtures with a density exceeding 1700 kg/m3 demonstrated superior durability characteristics. Furthermore, LWHPC mixes in both water/binder ratio groups displayed significantly low thermal conductivity with increasing lightweight aggregate content.