Perpetual Pavement

Combining the well-documented smoothness and safety advantages of asphalt with an advanced, multi-layer pavement design process...

Perpetual Pavement combines the well-documented smoothness and safety advantages of asphalt with an advanced, multi-layer pavement design process, that with routine maintenance, extends the useful life of a roadway to half a century or more. Pavements designed and constructed in accordance with the Perpetual Pavement concept will last, and last, and last.

How it Works

Perpetual Pavements use multiple layers of durable asphalt to produce a safe, smooth, long-lasting road. The Hot Mix Asphalt (HMA) design begins with a strong, yet flexible bottom layer that resists tensile strain caused by traffic, and thus stops cracks from forming in the bottom of the pavement. A strong intermediate layer completes the permanent structural portion, and a final layer of rut-resistant HMA yields a surface that lasts many years before scheduled restoration.

A Perpetual Pavement provides a durable, safe, smooth, long-lasting roadway without expensive, time-consuming and traffic-disrupting reconstruction or major repair.  Read more

Perpetual Pavement Synthesis  This comprehensive publication captures the activities that have taken place over the last decade, synthesizes the information in way that is useful to providing guidance for Perpetual Pavement design and construction, and provides a vision for further research and development to refine Perpetual Pavements.

PerRoad 4.4 uses the mechanistic-empirical design philosophy. The program couples layered elastic analysis with a statistical analysis procedure (Monte Carlo simulation) to estimate stresses and strains within a pavement. Version 4.4 provides design results as percentile responses and as conventional designs with transfer functions. In order to predict strains that would prove detrimental for fatigue cracking or structural rutting, PerRoad requires the following inputs:
• Seasonal pavement moduli and annual coefficient of variation (COV)
• Seasonal resilient moduli of unbound materials and annual COV
• Thickness of bound materials and COV
• Thickness of unbound materials
• Load spectrum for traffic
• Location for pavement response analysis
• Magnitude of limiting pavement responses
• Transfer functions for pavement responses exceeding the user-specified level for accumulating damage