Density, compressive strength, and modulus of elasticity: three properties that influence the efficiency of structural concrete

Abstract

An important application of physics in civil engineering is related to the physical and mechanical properties of materials to be used in modelling and construction of structures. Density and compressive strength of concrete are important properties related to this purpose. Particularly, when concrete density is lower than 2000 kg/m3 and compressive strength is larger than 17 MPa it considered as structural lightweight concrete. In this study, the effect of replacing conventional aggregate (sand and crushed stone) with thermally expanded clay aggregates is investigated. Physical and mechanical characteristics of lightweight concrete and conventional concrete are identified and compared. Four concrete mixes were prepared replacing partially or totally conventional aggregates with thermally expanded clay aggregates. One control mix made only of conventional aggregates was prepared. All samples were subjected to density, compressive strength, and modulus of elasticity tests. Density of mixes resulted to be between 10% and 50% lower than control mix, compressive strength had a slight decrease, and modulus of elasticity lost almost 40% of the control value. These data allow to confirm that combined mixes can be classified as lightweight structural concrete. However, the lower modulus of elasticity could represent a disadvantage which must be furtherly investigated.