Subgrade Reinforcement with Mirafi H2Ri

Eagles Canyon Raceway

  Engineer: Brazos Environmental

  Contractor: Reynolds Asphalt

   Date: November 2018

Project Goals and Specs:

Provide a long-term solution to address pavement distress caused by saturated soils and groundwater seepage.


The original raceway was constructed in the mid 1980’s. New ownership desired to reconstruct the aging raceway pavement system, as well as add turns and length to the formula one type raceway. The track was constructed over expansive soils which caused visual signs of distress at the pavement surface.. Groundwater seepage due to shallow bedrock was also discovered in many areas, which further impacted the poorpavement performance.

Subgrade reinforcement using Mirafi H2Ri
Site Conditions:

Severe cracking of the existing pavement existed throughout the site. It was determined that the cracking was likely due to construction of the pavementover moisture sensitive soils (expansive clays) and the presence of fluctuating groundwater levels and capillary action. As constant water seeped into the structural section of the pavement, varying levels of moisture of the expansive clays cause the soils to expand and contract at different rates which cause volume change induced stresses at the pavement surface. The layout of the raceway, including numerous turns and elevation challenges posed additional challenges. The solution had to be flexible to work around the various site conditions.

Identified Issues and Constraints:

The original project pavement design consisted of cement stabilized subgrade to treat the existing subgrade with CBR=1.5%. In addition, the section included 8 inches of flexbase and 4 inches of asphalt. The project team wanted to consider alternate stabilization for the project since the constructability of the cement stabilized base during saturated conditions would be problematic. Considering a high strength geotextile like H2Ri also speeds up construction schedule as there is no cure-time required.

Solutions / Final Application / Results:

The project team was able to eliminate the need to cement stabilize the subgrade and installed a geosynthetic reinforced pavement with Mirafi H2Ri, a high strength, moisture-management geotextile, without adding any additional thickness to the original section which included 8” of flex base and 4” of asphalt. Mirafi H2Ri provides both mechanical stabilization (through friction) and hydraulic stabilization through enhanced lateral drainage. As the geotextile continuously pulls moisture out of the pavement section, even in unsaturated conditions, this solution is a long-term defense against the problematic seepage.

The engineer was familiar with the Mirafi subgrade enhancement products from previous projects. Ultimately, the owner decided to deploy Mirafi H2Ri for the subgrade reinforcement and the management of groundwater.

Moisture Management / Enhanced Lateral Drainage - wicking nylons are incorporated into the geotextile during the manufacturing process, which adds the unique ability to laterally remove water from both saturated and unsaturated subgrades. For moisture sensitive soils, such as expansive clays, the ability to remove and normalize (reduce the spread over a large area) the moisture contents in the subgrade decreases permanent deformations at the pavement surface.

Mirafi H2Ri layed over expansive soils.
Optimization Highlights:

This Mirafi H2Ri solution eliminated the need to install a more expensive and invasive groundwater drainage system. The Mirafi H2Ri moisture management system provides a long-term solution to assist in keeping groundwater out of the pavement system.

Free Project Evaluation

Your roadways are constantly under attack from moisture, causing foundational layers to deteriorate quicker, resulting in rutting and cracking, which leads to costly maintenance or, worse, a complete reconstruction. We have partnered with TenCate to provide you with one of their most innovative technologies, the Mirafi H2Ri, perfect for separation, moisture management, reinforcement, confinement, filtration, and drainage. Identify how you can mitigate reflective cracking and extend the performance of your pavement projects.

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