Auto transport home >> Transport articles >> Preventive Maintenance and Holding Strategies

Preventive Maintenance and Holding Strategies

In accordance with the Ministry of Transportation's dedication to maintaining quality roadways while keeping costs low, MTO has been developing a program of pavement preventive maintenance to ensure long-term pavement preservation. This initiative improves pavement quality and durability, extends pavement's life cycle, and ensures more cost-effective, efficient repair methods. An emerging North American initiative, MTO has implemented preventive maintenance and holding strategies during recent years to maximize cost savings in repair operations and maintain pavement condition. These strategies are now competing effectively with the previous method used for pavement repair, the "worst first" approach.

The worst first method involves waiting until pavement has deteriorated significantly over its service life before initiating more costly resurfacing / reconstruction alternatives. It is estimated that $1 invested early in a pavement's life cycle can save in excess of $5 in the future.

The holding strategy involves temporary repairs that "hold" the pavement until funding for full rehabilitation of a roadway is acquired. Holding leads to a temporary yet effective repair while funding and asset planning efforts are diverted to other areas.

Preventive maintenance dictates a program of more regular roadway maintenance, even on roads in good condition, to ensure their long term durability and prevent more costly rehabilitation. It incorporates a number of methods that extend the service life of pavement while reducing long-term costs. In Eastern Region, two major methods of preventive maintenance used successfully are surface treatments (also called "seal coats" by some road authorities) and micro surfacing, two types of Ultra-Thin Treatments used only on roads with surface distress.

Surface treatments are asphalt surface treatments applied to an existing pavement surface. They entail a combination of emulsion and aggregate cover. When clean aggregate in the 6.7 to 9.5 mm size is employed, the surface treatment may be called a chip seal. This type of maintenance treatment is economical, easy to place, and prolongs the service life of pavement. It resists light to medium- volume traffic abrasion and provides waterproofing for the underlying structure. It also delays asphalt oxidization, or hardening, caused by exposure to the elements and resulting in brittle, cracked pavement.

Surface treatments have been used with success since the late 1980s in Ontario, often on thin asphalt pavements. Near Bancroft, different surface treatments were applied to Highway 28 between 2001 and 2003. They were used to repair surface deficiencies and protect the pavement surface with an expected service life of six to eight years. The treatment is showing good short-term performance, indicating that a surface treatment over hot mix is a viable preservation strategy in Ontario.

Micro surfacing, another Ultra-Thin Treatment used successfully by Eastern Region, is an emulsion-based slurry system composed of aggregates, asphalt emulsion, water, mineral fillers, and additives. It is an economical method for treating surface problems and improving skid resistance on roads with moderate to heavy-volume traffic. Micro surfacing cures within approximately one hour of application, allowing traffic on it quickly. It is also suitable for application under more diverse temperature and weather conditions than other emulsion-based paving systems.

Micro surfacing applications in Eastern Region have proven effective in preventive maintenance on Highways 7, 15, 28, 62 and 416 (formerly Highway 16). Besides a micro surfacing scratch and surface coat, certain projects have included asphalt strip repairs, centerline pre-treatment with micro surfacing, micro surfacing, and paved shoulder repairs. A project on Highway 401 near Ganonoque to eliminate confusing obliterated zone striping required only a single application.

Due to the initial success of micro surfacing, MTO is planning more preventive maintenance to be used this year on Highways 7, 7A, and 401 in Eastern Region. As well, more surface treatments are planned for roads in Eastern Region near Bancroft.

Based on Eastern Region's successful experiences with preventive maintenance and holding strategies, MTO will continue to implement these initiatives where appropriate while monitoring their performance. They will also fit well with the new Asset Management Business Framework that entails a strategic view of Ontario's transportation system as MTO moves away from a worst first approach. Preventive maintenance and holding strategies are alternatives that should be considered in the utilization of resources. As time progresses, the ministry anticipates greater savings as maintenance costs are reduced and pavement service life is increased. Besides protecting investments and improving pavement performance, preventive maintenance and holding strategies will also lead to fewer construction delays.