Reclaimed asphalt pavement, the processed material from milling or tearing up old asphalt, crushed and screened into stockpiles and metered into new mix through its own feed. RAP brings back both aggregate and aged binder, which cuts virgin binder and stone costs, but the old binder is stiff, so high-RAP mixes get a softer virgin grade or a rejuvenator. Mixes commonly carry 15 to 30 percent RAP, with surface lifts held to the low end, and plants often split it into coarse and fine fractions to control gradation.
RAP pile's soaked from last night's rain, drum's going to burn a ton of fuel and run cold till it dries out.
RAS, recycled asphalt shingles, comes up in the same conversations, but its binder is far stiffer and specs cap it at a few percent.
Also heard as
- reclaimed asphalt pavement
- millings
- grindings
Related terms
Milling
Grinding off the top of an existing pavement with a rotating cutter drum before repaving.
Drum plant
A continuous asphalt plant that dries the aggregate and mixes it with binder in one rotating drum.
JMF
Job mix formula: the approved recipe of gradation and binder content a plant must produce on a project.
Asphalt binder
The black, sticky petroleum cement that glues the aggregate together in an asphalt mix.