Geraldton Main Street Rehabilitation: Rebuilding from the Ground Up

Work on the Main Street Rehabilitation Project is revealing not only the scale of the construction underway, but also why this major investment is so important for Geraldton.

As the existing roadway has been excavated, crews have encountered large, uneven rock formations, degraded and inconsistently mixed sub-base materials, and pockets of organic material. These conditions help explain the significant heaving, cracking and uneven pavement that have affected Main Street for many years.

A road performs best when it is built on a strong and consistent foundation. During excavation, it was observed that some sections of Main Street rested on solid rock while nearby sections were supported by weaker mixed materials or organics. These materials respond differently to moisture, freezing temperatures and vehicle loads.

Organic and fine-grained materials can retain significant amounts of water. When that water freezes, it expands and can push the road upward. When the ground thaws, these materials can soften, compress and settle, resulting in uneven movement across the roadway. Over repeated freeze-and-thaw cycles, this differential movement can appear at the surface as heaving, dips and cracking.

“Once excavation began, it became clear how much the conditions below the old road varied from one location to the next,” said Marc Audet, On-Site Construction Project Manager for Belanger Construction “We have encountered high rock, weak mixed material and pockets of organics, sometimes within a very short distance. Removing unsuitable materials, levelling the rock and rebuilding the base in controlled layers is essential to providing the new road with a much more consistent foundation.”

Simply repaving Main Street would not have addressed these underlying conditions. The rehabilitation is therefore rebuilding the road from the ground up.

Crews are removing high and irregular rock formations to create a formation that is as level and consistent as reasonably possible. This helps reduce abrupt transitions between rock and softer ground—areas that can be particularly susceptible to uneven movement.

The project also includes the replacement of underground municipal services within the project area before the new road is constructed. Completing this work now ensures the finished roadway is not being constructed over aging infrastructure and reduces the likelihood that the road will need to be excavated in the future to address service failures.

Once the underlying ground has been properly prepared, the new road structure is being built using engineered materials and several layers of protection:

• Geotextile separates the existing ground from the new aggregate, helping prevent fine soils and weaker materials from migrating into and contaminating the new road base.
• Geogrid reinforces the road structure by interlocking with the aggregate and helping distribute vehicle loads across a wider area.
• Granular B Type II (B2) replaces degraded and inconsistent materials found beneath the old road. It is placed and compacted in controlled layers to create a strong and more uniform foundation for the remainder of the road structure.

“The old roadway was affected by very different materials moving at different rates,” said Doug Walsh of EXP, the Municipality’s project manager. “The new design creates a much more uniform road structure. By levelling the rock, removing unsuitable materials and incorporating geotextile, geogrid and properly compacted Granular B Type II, we are improving separation, reinforcement and load distribution. This will make the new road significantly more resilient to frost action and seasonal movement.”

Together, these measures are designed to provide a stronger and more consistent road base. While no roadway in Northern Ontario can be completely isolated from freeze-and-thaw conditions, the reconstructed Main Street will be better equipped to withstand frost action, seasonal movement and the stresses of everyday traffic.

Much of the most important work on this project will eventually be hidden beneath the finished road. The current excavation provides a rare opportunity to see both the conditions that contributed to Main Street’s past problems and the extensive work being undertaken to address them.

The Municipality recognizes that construction of this scale is disruptive and appreciates the continued patience and cooperation of residents, businesses and motorists.

This project is about more than replacing pavement. It is about renewing underground infrastructure and rebuilding the road foundation from the ground up to provide a stronger, more reliable Main Street for Geraldton for decades to come.