Improving Life-Cycle Performance with Pavement Interlayers

By Mike Skinner
Colorado Asphalt Pavement Association's The Road Ahead - Fall 2016 edition

In an environment of limited and decreasing budgets in the private and public sectors, it is increasingly important that investments made in pavement infrastructure are maximized to their fullest potential. Pavement interlayers, also known as geosynthetics, can be integrated into asphalt mix overlay applications to limit the intrusion of water and reduce the reflective cracking, thereby promoting long-term pavement performance.

Although there is no single solution that can prevent reflective cracking, pavements using interlayers have demonstrated significant savings on repeated maintenance costs over a pavement life cycle, whether for a new or for a rehabilitation construction project. Pavement interlayers extend the life of flexible asphalt pavements, delay and reduce the severity of cracking by reducing the pathway for water to enter pavements, and provide a moisture barrier that maintains the integrity and load-bearing capacity of the aggregate base.

Pavement interlayers are used in the construction of new roadways and rehabilitation of old pavements to protect the aggregate base, delay cracks and reduce their severity, and as reinforcement. The benefits include:

Aggregate Base Protection
Geosynthetics that form a moisture barrier when properly installed, protect the aggregate base from top-down moisture intrusion through the cracks, preserving the load bearing capacity of the aggregate base. Studies have shown that the life of a pavement can be extended up to 50 percent by preventing aggregate base saturation.

Crack Delay and Reduced Severity
Geosynthetics are designed to mitigate crack reflection and reduce the severity of cracks when they do return.

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