Properties of lightweight concrete made with core-shell structured lightweight aggregate

In this study, core-shell structured lightweight aggregates (CSA) were produced through the cold bonding method, by encapsulating an expanded perlite particle (as a core structure) within a shell matrix composed of cement, fly ash and expanded perlite powder. The effect of different curing regimes on the mechanical and microstructural properties of the CSA were studied. To enhance the characteristics of the aggregates produced, they were surface treated by a mixture of cement and silica fume, using two different treatment methods. Afterwards, the properties of lightweight concrete made of either CSA or expanded clay aggregate (ECA) were compared closely in terms of their potential economic and environmental benefits, in response to the high energy consumption associated with the production of ECA. The results revealed that curing at a relative humidity of 99% is the most appropriate curing method for CSA. In addition, treating the CSA surface contributes significantly to enhancing its bulk crushing strength, by about 14-18%. The findings also demonstrate the feasibility of using CSA to produce lightweight aggregate concrete, with a dry density and compressive strength ranging from 1115 to 1540 kg/m(3) and from 17.9 to 25.8 MPa, respectively, with a corresponding thermal conductivity range of 0.3169-0.6660 W/m.K. (C) 2019 Elsevier Ltd. All rights reserved.