Since the days of the Roman Gladiators, road builders and other inventive construction contractors have devised numerous methods for stabilizing soils. The materials introduced varied anywhere from seashells and wood chips to today's more popular and successful lime, flyash and cement.
Unstable soils are generally characterized as those unable to support a load, including those with excess moisture content and those with aggregate having minimal angularity-in other words, the stone is too smooth, preventing it from interlocking.
So the materials used to stabilize these soils have to offset the problem. They have to be locally available and in a bid situation, and they have to be cheap. The path to today's material markets must meet these parameters to be acceptable.
In order to be useful, these materials have to be processed, moved from the processing plant to the jobsite, then placed where they will do the most good. The recipe for a successful soil stabilization project includes just enough lime to stabilize the soil. Too little additive won't work and too much wastes money.
Spreadable
To fine tune this end of the process, Stoltzfus Spreaders, Morgantown, Pa., developed a line of soil cement spreaders that can accurately place lime, flyash and other materials. Stoltzfus is located in the heart of farm country in central Pennsylvania. They have over 58 years experience in solving the spreading problems of the agricultural industry.
Stoltzfus engineers had little problem adapting the concepts employed in the agricultural arena to meet the needs of their newfound construction materials market. Their highly regarded machines are known for their ability to spread precise amounts of material uniformly; the perfect product for the contractor trying to keep costs down.
Heads in the clouds
Soil stabilization technologies may have been around for centuries, but until recently no one really paid much attention to the content of the materials or the dust they created.
Concerns about the health effects of airborne respirable dusts have led to regulations that have established exposure standards for particulate that can cause lung diseases. In addition, spreading operations can produce a cloud of emissions that obscure visibility. These dust clouds create a safety hazard to workers as well as drivers that may be passing through the construction zone.
The public no longer looks the other way when it sees dust blowing around a jobsite and regulators are straining to levy fines for air quality violations to fund empty state coffers. The bottom line was Stoltzfus had to come up with a solution for the fugitive dust.
For more on the story, read the June issue of ROADS & BRIDGES.
