Recent advances in high strength lightweight concrete: From development strategies to practical applications

Lightweight cementitious composite has been used in construction for thousand years. However, before the Second World War, lightweight concrete was mainly limited to non-loadbearing blocks. With the increasingly demanding requirements of modern construction, especially in harsh environments, there is an urgent need to develop high strength lightweight concrete (HSLWC) capable of loading bearing purposes. The adoptions of supplementary cementitious materials, high-quality lightweight materials and fibers contribute to developing HSLWC, which enable the production of structural components. Numerous studies have been conducted on HSLWC with a compressive strength exceeding 40 MPa and a density below 2000 kg/m3. This paper aims to provide an in-depth review of HSLWC, covering its development strategies, functional and durability properties, and structural applications. Particular emphasis is given to the emerging technology of ultra high-performance lightweight concrete, characterized by low density, ultra high strength and superior durability. Compared to normal weight concrete, HSLWC offers better thermal insulation and fire resistance. The use of HSLWC in structures can increase load capacity and span, reduce seismic inertial forces, and improve structural efficiency. Numerous research and projects have demonstrated the feasibility and advantages of using HSLWC in various construction fields, including high-rise buildings, bridges and offshore structures. The excellent in-service performance of HSLWC in marine structures highlights its durability. To expand the applications of HSLWC in civil engineering, the paper proposes current opportunities and challenges that should be addressed to attract more attentions and foster further research in this area.