#9 - Engineering Material - Asphalt

A set of vocabulary terms and definitions covering asphalt production, testing methods, types of mixtures, and pavement failure mechanisms based on the ENEV 384 lecture notes.

Asphalt

A bituminous material that is either natural or refined from petroleum oil.

Tar

A bituminous material produced from coal.

Asphalt Production Byproduct

The residuum obtained from the atmospheric and vacuum distillation of crude oil.

ROSE (Residuum Oil Supercritical Extraction)

A process where asphalt is broken down into three components: asphaltenes, resins, and oil.

Asphaltenes

One of the three chemical components of asphalt used in the ROSE process to produce asphalt with desired properties.

Superpave

A mechanistic-empirical design guide developed by the National Cooperative Highway Research Program (NCHRP).

Penetration Test

Measures the consistency of a binder using a weighted needle of $100\,g$ loaded for $5\,sec$, recorded in units of $0.1\,mm$.

Penetration Grade 40-50

The hardest grade of asphalt typically used in hot regions.

Penetration Grade 200-300

The softest grade of asphalt typically used in cold regions.

Cutback Asphalt

A liquid petroleum asphalt produced by adding a solvent to asphalt cement.

Rapid Curing (RC) Cutback

Asphalt cement combined with naphtha, commonly used for surface treatments.

Medium Curing (MC) Cutback

Asphalt cement combined with kerosene, used for stockpile patches and prime coats.

Slow Curing (SC) Cutback

Asphalt cement combined with oil.

Seal coat

Emulsified asphalt applied to protect asphalt from oxidation, UV rays, traffic, and winter cracking.

Tack coat

Emulsified asphalt sprayed on an existing pavement surface by a distributor truck immediately prior to placing an overlay.

Fog seal

A light application of emulsified asphalt to an aged pavement surface to restore flexibility.

Slurry seal

A homogenous mixture of emulsified asphalt, water, fine aggregate, and mineral filler used to fill pavement surface defects.

High Float (HF) Emulsion

An emulsified asphalt that is more resistant to flowing.

Air Blown Asphalt

Asphalt produced by blowing air through molten asphalt to raise its softening point, making it suitable for roofing and waterproof paints.

Hot Mix Asphalt (HMA)

A combination of asphalt binder and aggregates designed for flexible pavements.

Marshall Stability

The maximum load a specimen can withstand when tested in the Marshall apparatus.

Marshall Flow

The deformation of a specimen at the point when the test load starts to decrease.

VTM

Voids in the Total Mix.

VMA

Voids in the Mineral Aggregate.

VFA

Voids Filled with Asphalt.

Rutting

A type of pavement failure characterized by the accumulation of permanent deformation in the wheel path.

Stripping

A type of failure involving the loss of hard bond between the binder and aggregate due to moisture.

RAP (Recycled Asphalt Pavement)

Old asphalt material that is reused to save more than $25\%$ in material costs and reduce environmental waste.