Investigating the properties of non-structural lightweight concrete incorporating polymer-coated cardboard waste

This study investigates the performance of lightweight concrete incorporated silicone rubber-coated cardboard waste strips (SCBWS), produced by coarsely shredding cardboard coated with silicone rubber, as a partial replacement for coarse aggregates in concrete at varying percentages (5%, 10%, and 15% by weight). The mechanical properties of the resulting concrete were evaluated, including compressive strength, splitting tensile strength, and flexural strength, as well as physical characteristics such as bulk density, thermal conductivity, and water absorption. The results indicated that the 5% SCBWS mixture exhibited the best overall mechanical performance, achieving a compressive strength of 14.8 MPa and a splitting tensile strength of 2.08 MPa. Flexural strength increased with the addition of SCBWS, being highest at 15% by weight. Furthermore, thermal conductivity decreased from 1.487 W/m·K in the reference concrete to 0.883 W/m·K at 15% SCBWS content. Additionally, the inclusion of SCBWS reduced both bulk density and water absorption, with the most significant reductions observed at the 15% replacement level. These findings demonstrate that SCBWS integrating enables the production of lightweight concrete suitable for non-structure and insulation focused construction application.