Long-Term Field Performance of Ready-Mix Recycled Aggregate Concrete

Presented By: Humera Ahmed, The University of British Columbia
Description: Concrete waste is the most prominent and permanent burden on landfills generated by the construction industry. A growing body of literature in lab settings has already recognized the importance and sustainability of recycling this waste in the form of recycled concrete aggregates (RCA) and substituting it for natural aggregates in the production of new concrete. However, intense utilization of RCA in the large‐scale industrial production of new concrete (structural and non‐structural) is not widely accepted by many international standards due to its high porosity, a disparity of source concrete, and lack of territorial field studies. Keeping this in view, the present research was planned in 2013 to provide an insight into the applicability of recycled aggregate concrete (RAC) to the Southern Interior of British Columbia (BC), Canada. In this research, the long‐term performance of two full‐scale field studies of the foundation system and municipal sidewalk constructed with ready‐mix RAC is presented. The results of this research are based on laboratory investigations and assessment of the in‐place long‐term performance of RAC made with different replacement levels of RCA. Long‐term performance is examined for 5 years in terms of in‐place compressive strength using rebound hammers. In addition to this, strength correlations developed specifically for RAC for the estimation of compressive strength based on rebound numbers are discussed. The results show that RCA has a significant potential of substituting natural aggregate in the production of new concrete of 25 and 32 MPa compressive strength. Furthermore, RAC shows a higher rate of compressive strength development after 28 days of curing and results in comparable long‐term compressive strength to conventional concrete. By providing an insight into the sustainable application of RCA in the production of new concrete,the results of this study can serve as a basis for updating the current standards in Canada.