By Susan Tighe
Understanding how recycled aggregates perform on Canadian roads.
By Susan Tighe
The Centre for Pavement and Transportation Technology (CPATT) is a
partnership between universities, the public sector and the private
sector that involves a board of advisors and a research team responsible
for the planning, management, and conduct of the research program.
The Centre for Pavement and Transportation Technology (CPATT) is a partnership between universities, the public sector and the private sector that involves a board of advisors and a research team responsible for the planning, management, and conduct of the research program. This is possible with the use of the central lab facility at the University of Waterloo, the main field lab facility, a test site at Waterloo Region’s Waste Management Facility, as well as a number of satellite test sites and liaisons with other labs.
The CPATT Test Track was constructed in June 2002. It was the result of a partnership between federal, provincial and municipal governments, private sector, and the university. The Test Track in located in the southeast corner of the Regional Municipality of Waterloo’s Waste Management Facility. Over the last 10 years, visitors from all over the world have come to see the Test Track and learn how it is being used to advance pavement engineering, not only in Ontario but across Canada.
In 2002, the Test Track consisted of a 700-metre-long test strip, with various asphalt mix designs, embedded sensors, various weigh-in motion devices, wireless data transmission, trenchless and trenched installations of high density polyethylene pipe and geogrid reinforcement. Now, the Test Track is 1294 m long and 8 m wide. It includes 15 different types of pavement including the five original asphalt surface mixes: Hot-Laid 3 (HL3), Polymer-Modified Asphalt HL3 (PMA), Stone Mastic Asphalt (SMA), SuperPave, Conventional Jointed Plain Concrete Pavement (JPCP) with 15 per cent Recycled Concrete Aggregate (RCA), JPCP with 30 per cent RCA, JPCP with 50 per cent RCA, and a Recycled Asphalt Shingles (RAS) section. The first portions of the Test Track, which contain two control sections and three flexible sections, were constructed in June 2002. The JPCP sections were constructed in June 2007 with a control section and varying percentages of RCA including: 50, 30, 15, and 0 per cent. The last section of the Test Track is a HL3 RAS mix design and it was constructed in 2009.
In partnership with the Cement Association of Canada, CPATT is conducting a research project where the general objective is to increase friction and noise absorption in concrete pavements. Previous research to increase friction and reduce noise production has been focused on creating different surface textures through macrotexture modifications. Due to the key role that microtexture has on pavement, the first innovative stage of this research involves the study of concrete response based on microtexture modification using nanotechnology, because nanotechnology acts on the concrete microstructure. The second stage of this research will be to create new geometrics on the top of concrete pavement through macrotexture modifications.
The research being done on recycled asphalt pavement is in partnership between CPATT, the Ministry of Transportation Ontario (MTO), the Ontario Hot Mix Producers Association (OHMPA), and the Natural Science and Engineering Research Council of Canada (NSERC). This research is aimed at fostering innovation for greener roads in Ontario, Canada. Ontario’s experience with low percentages of Recycled Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) has proved satisfactory in terms of fatigue, rutting, thermal resistance and durability. However, the opportunity to consider high percentages is present. Currently, RAP is limited to between 15 and 20 per cent since performance of the resultant HMA mixture is influenced by characteristics of RAP material, and quality control during production and processing, which includes mix design considerations and specification requirements.
For more information on our research projects, or to contact us about our research, please visit our website at www.civil.uwaterloo.ca/CPATT .
Susan Tighe, Director of the Centre for Pavement and Transportation Technology, University of Waterloo