Asphalt Base Repair Services
Base Repair for Asphalt Pavement
Pavement base failures are prevalent in Southern Louisiana due to factors such as weak soil, poor drainage from flat terrain, and a high water table. Addressing these issues effectively requires a thorough investigation and a systematic repair process to prevent future costly repairs.
Common Causes of Base Failures
Structurally Weak Soil: Inherent soil weaknesses can undermine the stability of the pavement base.
Poor Drainage: Flat terrain leads to inadequate water runoff, causing water to accumulate and weaken the base.
High Water Table: Elevated groundwater levels can saturate the base and subgrade, reducing their load-bearing capacity.
Base Repair Process
Marking the Repair Area:
The area to be repaired is marked with paint to outline the scope of work.
Saw-Cutting the Perimeter:
The perimeter of the asphalt failure is saw-cut to create clean, vertical walls, ensuring a neat and defined repair boundary.
Excavation and Disposal:
The damaged base, sub-base, and any soft sub-grade materials are excavated and properly disposed of.
Placement of Base Material:
New base material is placed in multiple lifts.
Each lift is compacted to the appropriate density to ensure structural integrity.
Additional Measures (if necessary):
If a solid sub-grade is not found, additional excavation may be required.
Geotextile fabric, geogrid, riprap, or a combination of these materials may be used to reinforce the base and provide additional stability.
By following these steps, the repaired pavement base will be structurally sound, capable of supporting the surface asphalt going forward.
Stone Base Repair
A stone base is the most durable and maintenance-free solution for base repairs. This is especially beneficial in Louisiana due to the stone base’s ability to allow water to pass through, preventing moisture buildup on one side that can weaken the sub-grade. Moisture buildup often results in hydraulic pressure, causing pavements to bulge upward, leading to bumps and cracks.
Asphalt, being flexible, performs best over a similar flexible material like stone. Using a rigid material below asphalt causes the surface to flex at different rates, leading to cracks around the perimeter of the less flexible material and allowing water to penetrate the surface.
Asphalt Base Repair
Asphalt base repairs, also known as full depth asphalt patching, provide a solid mass of asphalt. Many municipalities prefer this method for its ability to bridge a weak sub-grade and its ease of construction. However, there are several disadvantages to consider when using asphalt for base and sub-grade repairs.
First, a solid mass of asphalt will be less flexible than the surrounding asphalt, often causing cracks around the perimeter, which further damages the base and sub-grade. Second, in Southern Louisiana, wet bases and sub-grades often cause pavement failure. Since water takes the path of least resistance, failed pavement indicates where subsurface water is collecting. Replacing stone and soil with asphalt displaces the water, creating a larger area around the repair to collect water and further damage a greater area.
Finally, if the pavement is a future candidate for soil cement stabilization, the patches will need to be removed before that process can begin. The expensive process of removing thick sections of asphalt will also re-expose the poor sub-grade, restarting the cycle often repeated on the same section of pavement.
Concrete Base Repair
Some customers prefer using concrete to repair base and sub-grade problems. This method is similar to asphalt base repair, with the option of pouring concrete to the finish grade or leaving it 2 inches low and topping it off with asphalt. The advantages are similar to those of asphalt but with greater bridging strength.
However, concrete base repair shares the same disadvantages as asphalt base repairs, with increased cracking due to a greater thermal differential between asphalt and concrete and differences in the materials' flexibility. Additionally, asphalt milling costs increase, especially if concrete patches are not visible at the surface. This is because production slows to reduce the impact when milling equipment contacts the harder material. If these precautions are not taken, more costly damage to the milling equipment is inevitable.
