Canadian Technical Asphalt Association Proceedings 37th

Roadway rehabilitation using asphalt without the need for excavation on old, cracked, and oxidized asphalt pavements with water weakened, or non uniform support bases and sub-bases has often been attempted, usually with variable success.  Costs of excavation and roadbed replacement are expensive in terms of manpower, money, environmental damage, and usage delays. 

This paper describes the results of a joint program by the author, the District of North Vancouver, their annual paving contractor, and B.C. manufacturers of “high tech” asphalt and asphalt related products to rehabilitate roadways using asphalt without excavation.  The program parameters evolved out of the District’s past pavement rehabilitation experiences and builds on this knowledge base. 

The rehabilitation strategies detailed are compared for cost.  All were selected for ease of contractor installation, their requirement for inspection, amount of technical support, local availability, and life cycle performance.  The study is based on actual installations in the same geographic area.

Canadian Technical Asphalt Association Proceedings 40th

This paper presents laboratory and full scale field evaluation of rubberized wet process hot mix asphalt concrete.  Field evaluation took place on four projects for three separate municipalities with paving being done on six roads in October 1994 and July 1995. 

Rubberized asphalt cement binder is produced by the wet process.  Binder viscoelastic properties are improved with carefully selected modifiers that resulted from a two year research project.  Rub-Arb, a fully reacted and modified rubberized asphalt binder is then transported to the asphalt plant where no special equipment or plant modifications were required.  Three different dense-graded hot mixes were produced with maximum nominal size of aggregate being 20mm, 12.5mm, and 10mm.  Hot mixes were produced in batch, drum, and continuous (combination of drum plant and pug mill) plants.  Once produced, rubberized hot mix is placed and compacted with conventional equipment.  This paper presents, in detail, the construction practice implemented on each project, including initial difficulties, proposed solutions, results and deviations from standard construction practices. 

Information provided in this paper presents a collection of data from the asphalt rubber binder producer, asphalt plant operators and contractors involved in all four projects and could be useful reference material for all involved with rubberized asphalt concrete.

BCIT Road Construction

Introduction course material in road construction practices.

ASTM - Asphalt Cement Binders

In recent years, significant advances in asphalt modifications have been achieved, particularly in the field of polymer modified asphalt cement binders.  Concurrently, environmental concerns and recycling processes are becoming a part of everyday life.  Tall oil pitch (TOP) is a by-product of the kraft process in the pulp and paper industry.  The company’s research and development team has conducted development programs and intensive testing of physical properties of tall oil pitch modified cement binders.  Obtained results show that tall oil pitch strongly influences rheological properties of asphalt cement.  These blends have higher penetration, lower viscosity, and are more temperature susceptible that original asphalt cement.  Blends also have excellent wetting properties of aggregate.

British Columbia Business Magazine. October 1996 Issue.