By Mayuri Punithan
University of Waterloo researchers are using recycled tires to perfect a permeable paving product so it can be used for commercial purposes to reduce the load on stormwater systems.
Tamanna Kabir, a PhD candidate and Hanaa Al-Bayati, a research associate, both working with Susan Tighe, Professor, Civil and Environmental Engineering at Waterloo are experimenting with different formulas to determine which one is most effective. For example, would a formula that contains mainly polyurethane be the most durable? To test each formula’s effectiveness, they will install test plots in commercial parking lots and observe the pavement’s performance. Previously, they only experimented in a lab.
The research project Development of Porous Rubber Pavement for the Canadian Climate is supported by a $180,000 Mitacs Accelerate award and a partnership with Waterloo’s Centre for Pavement and Transportation Technology (CPATT) and Porous Pave.
Typically, pavement used in parking areas is impermeable, thus unable to absorb any rainfall, causing the runoff to run into drains also known as stormwater systems. Unfortunately, these stormwater systems are undersized, causing the rainfall to flood roads. With climate change leading to more frequent and intense rainfall, flooding concerns have spiked. Many communities now require new buildings to keep on rainwater on site, which leads to thousands of dollars spent on catchment systems under the pavement.
Becky Shaw, a Waterloo alumnus and Director of Marketing at Porous Pave, says flooding has become a worldwide issue. CBC reported that during the summer of 2018, several underpasses and parking garages were flooded, with some cars completely covered with water. Police officers also had to rescue two men trapped in a water-filled elevator. The issue isn’t restricted to Canada, as flooding is prevalent in tropical countries such as India. In June of 2021, floods hit the state of Maharashtra, which have killed around 251 people and caused around 100 people to go missing.
Not only does flooding create safety and environmental concerns but also monetary. According to the Insurance Bureau of Canada “insurers spent $1.9 billion annually, on average, between 2009 and 2019 on catastrophic flooding claims, compared with an average of $422 million per year in the 1983–2008 period.” This four-fold spike was due to flood loss and the majority of claims were residential. This issue affects not only companies but also consumers. For instance, insurance coverage has increased from $75-$100 to $300 per year, mainly due to weak infrastructure.
The project underway with Waterloo researchers and Porous Pave is working to combat flooding like this using recycled tires. Using permeable pavement will allow stormwater to percolate down and back into groundwater instead of directly into storm drains.
For Porous Pave owners Jim Roth and Julie Redfern, the company started when they were dissatisfied with their asphalt driveway as it was full of cracks. When searching for a new driveway, they became acquainted with Porous Pave Inc. in Michigan and eventually became the Canadian distributors for Porous Pave. They have since modernized the way they install Porous Pave and with this project hope to expand into commercial parking.
Porous Pave uses recycled rubber tire pieces, granite aggregates, and polyurethane to create permeable pavement. For every square foot, it can absorb about 5,800 gallons of water per hour, which prevents storm water runoff to go into the drain. Every 1,000-square-feet of 2-inch Porous Pave saves approximately 300 tires from the landfill.