Development and Structural Performance Assessment of Low-Carbon Concrete Using Recycled Concrete Aggregates and Secondary Materials

This thesis investigates the structural performance of low carbon concrete (LCC) developed with various proportions of recycled concrete aggregates (RCA) and supplementary cementitious materials (SCMs) as sustainable material alternatives to conventional concrete materials. Extensive materials testing and analysis of existing literature found that RCA sources possess up to 21% lower bulk specific gravity (BSG) and over 200% higher water absorption values relative to natural aggregate sources. The effect of RCA within experimental within mixtures was governed by the aggregate and mortar strength properties and relied significantly on the strength class of the resultant mixture with compressive/tensile strength reductions up to 41% observed.

Mixture design optimization of LCC mixtures was found to improve the alignment of actual and theoretical mixture free-water proportions and effectively improve the mechanical strength properties of LCC mixtures, with mechanical strength values up to 49.8 MPa achieved. Full-scale development and testing of 2-meter reinforced concrete beams subject to 4-point flexural testing found that LCC mixtures can achieve comparable and even superior flexural and serviceability properties (+3% higher) relative to conventional concrete mixtures, with 39 - 69% higher experimental values reported relative to CSA A23.3-14 factored strength empirical predictions. The cumulative findings from the thesis program confirmed that LCC mixtures could be utilized as a suitable concrete alternative within structural applications while also serving as a sustainable alternative.