Beating the Curse of Winter – the Pothole – Thanks to Tanks
There are so many wonderful things about winter – snowmen, Christmas lights, snow angels and holiday baking. But there is one major curse, especially for those living in the North: the dreaded and destructive pothole.
You probably don’t realize it, but the fix for potholes – and even the very road you drive on – would not be possible without liquid terminals. Asphalt is stored in liquid tanks before it is deployed to repair or construct roads and highways, parking lots, railway tracks, ports, airport runways, bicycle lands, sidewalks and some sports areas.
Asphalt pavement is a mixture of aggregates, binder and filler. Crushed rock, sand, gravel or slags are common aggregates used in asphalt mixtures. More recently, waste and by-products, such as construction and demolition debris, are being used as aggregates, which increases the sustainability of asphalt.
Asphalt binder – most commonly bitumen -- connects the aggregates into a cohesive mixture. Bitumen is a substance produced through the distillation of crude oil that is known for its waterproofing and adhesive properties. Bitumen production through distillation removes lighter crude oil components, such as gasoline and diesel, leaving the “heavier” bitumen behind.
The Storage and Handling of Asphalt
Strong, long-lasting and low-maintenance asphalt requires an asphalt binder that has universal properties, including a constant temperature and consistency. Achieving that goal requires proper handing and storing.
Asphalt Magazine, in an article, spoke with several representatives who specialize in asphalt handling and storage and asked them what they considered the most important aspects of their business. They said the key aspects of successfully storing and handling liquid asphalt include heating, permitting, safety, transporting, tank construction, tank management, environmental control and quality control.
That means asphalt storage service companies, including many ILTA members, have a big job to ensure consumers receive high-quality product. Keeping the binder at the right temperature is imperative for any asphalt storage facility. To do this, terminals use fire tubes or, more recently, transfer fluid through submerged tubing.
Because asphalt needs to stay hot, safety is of utmost importance to asphalt terminal and storage companies. Asphalt is combustible, but not flammable, meaning that it can – like a pile of lumber – catch fire, but only in rare circumstances when a spark is applied. Worker safety is another consideration. Because asphalt is kept at elevated temperatures to meet customer needs, operators need to guard against burns. Even a pinhole-sized leak can be dangerous, so terminal operators constantly maintain and inspect their facilities.
Asphalt is typically transported via ship, barge or rail into the terminal and transported out via truck tankers. Steam engineers supervise the unloading and heating of railcars while the asphalt – heated at or above 300 degrees Fahrenheit – is pumped from the cars into the tank. After storage, the asphalt is typically transferred, under supervision, from the tank to a tanker and shipped to the customer.
Asphalt tanks, like all liquid storage tanks, are capital intensive and must meet stringent design and construction standards. But for asphalt tanks, it isn’t just the steel and pipelines that are expensive. It’s also about installing and maintaining the heating coils, insulation and transfer racks. After construction, terminal operators continue to manage diligently all aspects of operations, including heating, and maintaining gauges and floats in the tanks – to ensure that the tanks aren’t overfilled – and ensuring that the liquid asphalt stays above the coils, so it doesn’t overheat and change the chemical properties. The operators also carefully manage the loading, unloading and storage, and ensure safety and quality control.
So, as you drive on a smooth road this winter and throughout the year, be sure to thank tanks!