Project Highlight: Addressing Poor Subgrade in Asphalt Paving
At Century Paving, we recently encountered a challenging asphalt paving project where poor subgrade conditions were discovered after the existing pavement was removed. This type of situation can significantly impact the longevity and performance of the new asphalt surface, making it crucial to address the underlying issues before proceeding.
The Challenge
Upon exposing the subgrade, it became evident that it lacked the necessary stability to support a long-lasting pavement structure. While cement stabilization is often the best solution for reinforcing weak subgrade, the client’s budget constraints made full-area stabilization unfeasible. To provide a cost-effective alternative, we proposed a hybrid approach:
- Half of the project area received full cement stabilization – This process involved mixing cement into the subgrade, compacting it, and allowing it to cure before applying the new asphalt surface.
- The other half was completed with a grind and overlay method – This involved milling the existing asphalt, compacting the existing subgrade as much as possible, and then applying a new layer of asphalt.
Pros & Cons of the Hybrid Approach
Cement Stabilization (Full Depth Repair)
Pros:
- Provides a solid, long-lasting foundation
- Reduces the risk of future cracking and rutting
- Improves load-bearing capacity, making it ideal for high-traffic areas
- Extends the overall lifespan of the pavement
Cons:
- Higher initial cost due to materials and labor
- Requires additional curing time before asphalt placement
Grind and Overlay
Pros:
- More cost-effective in the short term
- Faster turnaround time, allowing for quicker use of the roadway
- Provides a refreshed surface with improved drivability
Cons:
- Does not address underlying subgrade weaknesses
- More susceptible to premature cracking and failure
- Reduced lifespan compared to a fully stabilized subgrade
Durability & Lifetime Expectations
With proper cement stabilization, the pavement can last 20-30 years with routine maintenance, significantly reducing the need for major repairs. In contrast, the grind and overlay section may last 8-12 years, depending on traffic loads and environmental conditions, before requiring more substantial repairs or resurfacing.
Future Considerations
While this hybrid approach allowed the client to stay within budget while improving overall pavement performance, we recommend:
- Routine maintenance, including crack sealing and sealcoating, to maximize the lifespan of both sections.
- Monitoring the performance of the grind and overlay section for early signs of distress.
- Future budgeting for full-depth stabilization in areas where failures become evident.
At Century Paving, we work closely with our clients to balance budgetary constraints with the best possible solutions for durable, long-lasting pavement. By offering flexible options like this hybrid approach, we ensure our projects meet both financial and structural needs.
If you’re facing similar challenges with subgrade stability, contact us today to discuss the best approach for your next paving project!