Balanced Mix Design

Asphalt specifications provide a framework for designing and producing consistent pavement mixtures. Requirements for binder grade, aggregate properties, air voids, voids in mineral aggregate, and other volumetric characteristics give engineers measurable criteria for evaluating an asphalt mixture before it is implemented for a roadway project.    Those requirements remain important. But the questions facing the asphalt industry have become more complex.    Technologies like higher reclaimed [...]

By incorporating reclaimed asphalt and recycled asphalt materials into new mixtures, producers can reduce reliance on virgin materials, lower costs, and support circular economy initiatives. However, higher reclaimed asphalt pavement (RAP) content introduces new performance challenges that must be carefully managed to ensure long-term pavement durability.    The primary challenge stems from the aged binder contained within reclaimed asphalt pavement. Over time, asphalt [...]

The use of reclaimed asphalt and recycled asphalt materials is becoming increasingly widespread. High-RAP mixtures, or those defined as those containing more than 25% RAP by total mix weight, can offer significant environmental and economic benefits by reducing reliance on virgin aggregates and binder.    However, increasing RAP content can introduce performance challenges. The aged binder in RAP is typically stiff and brittle, which can negatively impact cracking resistance and long-term durability. [...]