Equivalent CO2 Emissions and Construction Costs of Buildings Designed Using Recycled Aggregate Concrete

Growing environmental concerns and lack of a sustained source of aggregate resources, have resulted in increased research dedicated to concrete produced with a variety of recycled and secondary materials. Despite the environmental benefits of recycled concrete aggregate (RCA), compared with conventional aggregates, the use of these materials often results in significantly lower mechanical properties of the resulting RCA concrete, requiring increases in cement content or structural dimensions in order to obtain similar strengths. In order to quantify and better understand environmental benefits of RCA concrete, a series of hypothetical case study structures were designed and analysed for equivalent CO2 emissions and costs during construction. In cases where higher quality RCA was available the reduction in eCO2 emissions was determined to be as high as 13.7%. Even with lower quality RCA, emission reductions of up to 8% were observed with certain alterations to structural design. It was concluded that when utilizing RCA concrete in new construction, the quality of the material available was the main factor in determining the degree of reduction in eCO2 emissions and the costs. Additional areas of further research were determined including more Lifecycle Assessment impact categories, RCA concrete structure assessment throughout service life, and analysis of additional building types.