Optimisation of concrete mixtures made with crushed clay bricks and roof tiles

The main purpose of this paper is to show the possible applicability of concrete made using partial replacement of natural aggregate with crushed bricks and roof tiles in load-bearing structures. In total, 62 different concrete mixtures with crushed bricks and roof tiles were made based on Box-Behnken design and experimentally tested. The selection of acceptable concrete mixtures was chosen according to experimental results and mathematical models of required properties (density, slump, compressive strength, tensile strength and modulus of elasticity). An optimal concrete mixture for a precast concrete beam and block floor system was chosen according to multi-criteria decision process. The applicability of concrete mixtures for precast concrete block and beam floor systems was tested regarding the requirements set out in standards HRN EN 15037-1:2008 and HRN EN 15037-2:2009.