Balanced Mix Design Archives

A byproduct of changes in bitumen quality is the trend for engineers to formulate asphalt mixes using a balanced mix design approach. This relatively new method accounts for variable bitumen specifications while prioritizing adherence to performance standards. Balanced mix design also allowed for incorporation of additives that can enhance the functional properties of a mix to improve performance outcomes. Rather than relying solely on binder or aggregate specifications to meet performance standards, all aspects of the mix (binder, aggregate, modifiers, and additives) are formulated to balance factors such as fatigue, rutting, and cracking characteristics.

Characteristics of RAP

The asphalt that is part of RAP is old and aged primarily through exposure to the elements. Compared to virgin asphalt, it is stiff, subject to premature cracking and fatigue failure. Simply put, its high-temperature characteristics have increased, its low-temperature characteristics and fracture toughness have decreased. Technically, when used in a mix design, the BBR S(60) increases, and them [...]

How to use RAP

Everyone knows the value of RAP. But what is the best way to use it? Conventional wisdom suggests (AASHTO M 23) that one can use up to 15% RAP without changing the asphalt grade specified. When you want to use 15-25% RAP, it is suggested that you use one grade softer asphalt for your mix and when you use [...]

Why You Should Use Recycled Asphalt Pavement

Why should you use Recycled Asphalt Pavement (RAP)? The simple answer: Save money while maintaining performance!! RAP reduces your need for virgin asphalt. RAO reduces the need for virgin aggregate. Save on your raw material costs. Conserve non-renewable resources. Reduce the amount of construction debris going into landfills!! The cost savings you realize will, of course, depend on the [...]

ReLIXER™ for 100% RAP Mixes!!

It is well known that ReLIXER™ is a great asphalt rejuvenator that allows you to maximize the RAP content while meeting project specifications. This high performance, “Green”, engineered bio-oil blend rapidly penetrates and rejuvenates asphalt reducing the virgin asphalt load in mixes that contain 40-60% (or more) RAP. But, did you know that these same features are allowing [...]