Recycled concrete aggregate in concrete pavements: A five year study on its effect on pavement performance

Recycled Concrete Aggregate (RCA) from demolished concrete is becoming increasingly available. Its use in the construction of new concrete pavements provides both environmental and economic benefits. The recycling of waste concrete as aggregate reduces the demand for virgin aggregates, of which there will be a critical shortage in the future. The use of RCA also protects the landscape and the environment by deferring the need to open new quarries, reducing the impact on landfills and decreasing energy consumption. Four pavement test sections were constructed in 2007 at the University of Waterloo's Centre for Pavement and Transportation Technology (CPATT) test track facility at the Region of Waterloo's waste management site. The test sections contain varying amounts of RCA in the concrete mix. Instrumentation was embedded in each section to assess the effects of environmental factors, including temperature and moisture gradients, on long-term pavement performance. Each test section was provided with sensors to measure strains, slab curling and warping, joint movement and concrete maturity. This paper presents a brief overview of the design and construction of the CPATT RCA sections, as well as a five-year performance evaluation of the pavement sections using sensor data and visual condition survey results. To date, comparable performance has been observed in all RCA sections, in comparison to the control section, suggesting that RCA is a suitable component for durable, long-lasting concrete pavements.