2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Daniel Pickel, University of Waterloo
Dr. Susan Tighe, CPATT - University of Waterloo
Precast concrete pavement is constructed from prefabricated panels, which are transported to site and placed contiguously. Precast concrete pavement used for pavement repairs has an expected service life of 20 years or more. To achieve this long-term performance, it is essential to provide a stable and uniform support underneath the panels. Inadequate support can induce stresses in the panels, leading to cracking and premature failure. Precast concrete inlay panels (PCIP) are a unique type of precast pavement, developed to rehabilitate high-volume asphalt highways exhibiting structural rutting issues. In 2016, a PCIP trial section was installed on Highway 400 in Ontario, Canada. The installation was performed by partially milling the existing asphalt, preparing a panel support, then inlaying panels into the roadway. Three different types of panel support conditions were constructed; they are referred to as asphalt-supported, grade-supported, and grout-supported. The support condition is prepared at the asphalt-panel interface and each type varies in the materials, design, and construction method.
In service, precast panels are exposed to environmental conditions that induce thermal gradients across the slab thickness, causing panel warping and curling. The thermal gradients exacerbate panel stresses caused by traffic loads and self-weight; therefore, environmental effects can significantly influence precast concrete pavement performance. To monitor the temperature effects in the PCIP trial section, earth pressure cells (EPC) were installed at the asphalt-panel interface to measure the pressure caused by panel warping/curling over time.
The purpose of this research is to evaluate the performance of the three support conditions using the EPC field data and finite element modelling. The EPC data collected over the first two years of service was analyzed to identify seasonal trends, data correlations, and similarities and differences between the support condition types. Finite element analysis of the PCIP was performed for comparison between the support condition alternatives and for comparison with the field data. For each type of support, a three-dimensional model of the PCIP was created using the finite-element program ABAQUS. Linear thermal gradients, of varying magnitudes, were applied to the panels. The pavement responses for each support condition were then evaluated and compared. Based on these results, the optimal support condition for PCIP performance under thermal loading can be recommended. This provides insight into potential improvements for future PCIP installations and may be applicable to other types of precast concrete pavement.