With the current changes in bitumen quality stemming from global sourcing and decreased focus on bitumen production by suppliers, engineers are looking for novel approaches to achieve performance requirements in asphalt mixes without relying on producers to meet specifications. This has led to the development of a balanced mix design in asphalt, which helps engineers formulate mixes that [...]
TRANSCRIPT FROM VIDEO: When using Reclaimed Asphalt Pavement in mixes was first introduced, the common belief was that the only modification needed was to soften the binder before adding RAP to a mix. However, research has demonstrated that while viscosity is an important property to consider, additional functional characteristics need to be restored for the resulting roadway [...]
TRANSCRIPT FROM VIDEO: The approach used depends on the specifications adopted for liquid binders in a given jurisdiction, country, or region. Some locales will set softening point and penetration specs, some will use binder viscosity specs, and yet others may rely on performance grade specs.  In all cases, rejuvenator dosage is determined by blending virgin binder, extracted [...]
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 [...]