Pavement Management

Pavement Management

“Pavement management” refers to a systematic process of maintaining, upgrading and operating a network of pavements and involves three major components: the pavement life cycle, the costs associated with this life cycle and pavement management systems.

Standard Washington State Hot Mix Asphalt Types

Standard Washington State Hot Mix Asphalt Types

This section lists the standard HMA  mixes used in Washington State both today and prior to changing from the Hveem mix design method.  Most modern HMAs are listed to designate both the nominate maximum aggregate size of the mix and the PG (Preformance Grade) of binder used in the mix (e.g. – Class 1/2 inch PG 58H-22).

Water Bleeding and Pumping

Water Bleeding and Pumping

Water bleeding (left two photos) occurs when water seeps out of joints or cracks or through an excessively porous HMA layer.  Pumping (right-most photo) occurs when water and fine material is ejected from underlying layers through cracks in the HMA layer or out the sides of the HMA layer under moving loads.

Transverse (Thermal) Cracking

Transverse (Thermal) Cracking

Cracks perpendicular to the pavement's centerline or laydown direction.  Usually a type of thermal cracking.

Stripping

Stripping

The loss of bond between aggregates and asphalt binder that typically begins at the bottom of the HMA layer and progresses upward.  When stripping begins at the surface and progresses downward it is usually called raveling.

Slippage Cracking

Slippage Cracking

Crescent or half-moon shaped cracks generally having two ends pointed into the direction of traffic.

Rutting

Rutting

Pavement rutting is defined as surface depression in the wheelpath.  Pavement uplift (shearing) may occur along the sides of the rut.  Ruts are particularly evident after a rain when they are filled with water.  There are two basic types of rutting: mix rutting and subgrade rutting.  Mix rutting occurs when the subgrade does not rut yet the pavement surface exhibits wheelpath depressions as a result of compaction/mix design problems.  Subgrade rutting occurs when the subgrade exhibits wheelpath depressions due to loading.  In this case, the pavement settles into the subgrade ruts causing surface depressions in the wheelpath.

Since the advent of Superpave mix design technology and the follow-on predictive testing now used in hot mix asphalt (HMA) design evaluation, rutting has largely been eliminated as a concern when the pavement structure and HMA are properly designed.  In Washington State, the Hamburg Wheel Test device has been in use since 2010 to evaluate HMA designs for rut resistance prior to approval for use.  The exception to the rule, for both asphalt and concrete pavements, is in areas where extensive studded tire use is common.