By Bob Humer, P.E.

The longitudinal joints are often the weakest link in an otherwise good performing asphalt pavement. 

Unless creating a hot-joint by paving in echelon, the typical cold joint will have less density than the center of the paving lane. This occurs for dense-graded mixes, and to a lesser extent for SMA mixes and asphalt-rubber mixes. The deterioration of the joint area is caused by it being permeable. The permeability leads to water and air intrusion, resulting in binder oxidation and a scouring of the mix matrix caused by the combination of traffic and water intrusion. This leads roads to early maintenance/repairs of the joint area, and on airports to earlier-than-anticipated overlays to avoid the risk of Foreign Object Damage (FOD) from dislodged mix. These are the costly results of failing joints and the associated reduction in service life. 

Should you consider specifying it?

By Wayne Jones, P.E.

Before we delve into jet fuel resistant (JFR) asphalt pavements, perhaps a bit of review is in order.

According to the Asphalt Institute’s “MS-25 Asphalt Binder Testing” manual, asphalt cement “is the dark brown to black cementation material in which the predominant constituents are components that occur in nature or obtained in petroleum processing.”