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.

Video: How are Reclaimed Asphalt Pavement (RAP) mixes evaluated for balanced mix design?

TRANSCRIPT FROM VIDEO: There are several approaches to evaluating RAP in balanced mix design. Balanced mix design considers the functional characteristics of the mix and seeks a compromise between competing properties in order to meet the required specifications for roadway performance. For example, a balanced mix design will look to offset the impact of stiffness compared to [...]

By Kate Brough|2025-02-10T19:47:01+00:00January 15th, 2025|Categories: Balanced Mix Design, Blog, Webinar|Tags: ReLIXER, Sustainability|Comments Off

Video: What are the steps for processing Reclaimed Asphalt Pavement (RAP) for a mix?

TRANSCRIPT FROM VIDEO: Asphalt mixes incorporating RAP should be evaluated for key performance specifications. To do this, samples from the fractionated RAP stockpiles are taken to a lab for analysis. Determining the amount of RAP viable in a balanced mix design will depend on the established mix specifications. Typically, by using a blend from different fractionated particle [...]

By Kate Brough|2025-02-10T19:46:10+00:00January 8th, 2025|Categories: Balanced Mix Design, Blog, Webinar|Tags: ReLIXER|Comments Off

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 [...]