Careful haul road design and a well thought out maintenance plan are wise investments. "An efficient and well-planned haul road can reduce operating costs of most jobsites," says Mike Tolman, market segment manager - North America, Construction, Port and Industrial Tires, Michelin Earthmover Tires.
Haul roads should not be an afterthought. "The most common mistake for haul roads is lack of planning," says Tim Good, global customer account manager OTR tires, Goodyear. "It is not enough just to get between points A and B. Contractors must consider safety, efficiency and tire and equipment life. Haul-road design must consider the material used, road width, grade and crown, curve radius and super elevation."
You also need to consider the equipment that will use the haul road. "Sometimes when designing roads, the equipment that is going to be running on those roads is not taken into consideration — only the equipment being used to build the road," says Tolman. "The materials used to build the roads play a very important part, particularly when the sites are in rainy areas."
Tire choice is also critical. "The design of the haul roads needs to match up to the rubber compounds of the tires being used on a particular site," says Tolman. "For example, certain compounds are better suited to short hauls vs. longer hauls, and if used in the wrong application, the tires can be damaged to the point that they are no longer serviceable."
Every jobsite and type of haul road requires a unique approach. Consider the case for motor wheel scrapers. "Scraper haul roads are usually a short-term requirement and they are changed frequently during a job," says Good. "The top priority for a scraper operator is ‘don't spin the wheels'. Therefore, minimize grade or plan to shut down scraper operations during bad weather if the grades are steep. In addition, use a push dozer with a flat blade or a two-scraper push-pull arrangement when loading."
Don't over water
Construction jobsites tend to be around more populated areas where particulate emissions are closely monitored and fines for non-compliance can be steep. "So the tendency is to over water," says Roger Best, senior field engineer, Bridgestone Firestone Off Road Tire.
Water can actually be detrimental to tires working off-road. Standing water should be avoided. "The water acts like a lubricant," says Best.
It can also hide holes and rocks, which may damage the tires. "While water should be used for dust control, tires should not work in standing water," says Good. "Put simply, do not load or dump in standing water. If the loading area of the pit floods, pump it dry."
Also avoid continually spraying the roads using water trucks. "We recommend spot watering instead of continuous flooding of the roads," says Tolman. "Continuous watering tends to flush out and deteriorate the road base, which will require the site to resurface the road constantly. From a safety standpoint, too much water on the road makes it very slippery and particularly dangerous if the vehicles are coming downhill with a load."
When watering a haul road, a little driver training can go a long way. "The best way to water a haul road is to use an on/off pattern and let the tires carry the water from the wet areas to the dry," says Good. "For example, water trucks should spray 200 yds. of haul road, followed by 50 yds. left dry, followed by 200 yds. watered. In addition, operators should avoid two passes of the water truck without some drying time in between."
Design for drainage
Proper sloping of haul roads keeps them dry. "Crowning haul roads is key to keeping water from pooling," says Good. "Road crown of 3% is ideal. A crown of less than 3% allows the water to flow to low spots where tires can sustain damage and increased wear. Crowning that exceeds 3% causes uneven tire loads."