Porous Rubber Pavement—In Situ Performance Evaluation of Stiffness and Friction in Canada

Porous Rubber Pavement (PRP) is a relatively new material for low-trafficked pavements. This material consists of rubber aggregates, granite aggregates and polyurethane as a binder and is proportioned to attain a very high content of interconnected air voids. PRP has widespread environmental and safety benefits. While conventional impermeable paving materials interrupt our natural hydrological system by replacing natural soil surface, porous rubber pavement could reduce surface runoff, maintain the underground water table and improve water quality by its filtering capability. However, this low-impact design material is not currently widely used in pavements. Specifically, in Canada, its use is only limited to low volume traffic and low driving speed areas like parking lots and driveways. As a pavement material, its performance is still unexplored for the Canadian climate. Exhaustive research has been designed to investigate this material in this climate. This paper presents a part of the initial investigation of this material, which evaluates the performance of the existing PRP in terms of its strength and friction on the field. To examine the stiffness of this material, Lightweight Deflectometer was used. Friction is examined and compared using British Pendulum Tester and T2GO friction analyzer. The average Modulus of Elasticity of PRP is noted to be between 33 and 37 MPa that is significantly lower than conventional asphalt pavement. Average BPN was found to be between 57 and 74 and frictional values significantly reduced (almost 22%) under the wheel path. T2GO results also show a lower coefficient of friction value below 0.4 under the wheel path. Although both of the friction analyzing equipment show a similar trend, the T2GO produced more consistent results. The overall result shows that the stiffness of PRPs is considerably low as a pavement material. However, it exceeds the frictional threshold value for pavements. This study provides insight into the existing performance of PRP and the basis for future studies to improve its performance for broader pavement applications.