A Parametric Study to Assess Lightweight Aggregate Concrete for Future Sustainable Construction of Reinforced Concrete Beams

Lightweight aggregate concrete (LWC) is an attractive alternative to conventional concrete in building construction. It leads to lighter self-weight in beams and floor slabs and thus might have a positive impact on reinforcing steel consumption, also reducing the loads withstood by columns and foundations. However, LWC may increase cement consumption to maintain the required concrete compressive strength. This study presents compact equations for the design of reinforced LWC beams and subsequently applies them to a parametric analysis programmed in MATLAB. The aim of this analysis is to obtain an estimation of the equivalent carbon dioxide emissions associated with steel and cement consumption if using LWC instead of conventional concrete. The analysis involves more than 3 million beams simulating real scenarios by varying different design parameters, such as mix design, concrete strength, span length and applied loads and verifying both Ultimate and Serviceability Limit States. Whereas LWC of density equal or below 1600 kg/m3 does not seem to be feasible when trying adequately control cement content, the study shows that LWC with densities of 1800 and 2000 kg/m3 would not have a negative impact on the carbon dioxide emissions and would adequately comply with the various design restrictions