Monday, July 19, 2010

Cold, Colder, Really Cold, and Construction

There are four seasons in the year.  When you are from the northern latitudes, they are cold, colder, really cold, and construction.  Construction season is in full swing and many of you have probably noticed the extra chips in your windshields by following too closely behind that asphalt-laden dump truck.  You may also have noticed the diesel belching, earth moving equipment slowing your commute in an effort to shave 30 seconds from your daily trek when construction completes... sometime next year.  But have no fear my tree-hugging aficionados, not only is that off-road equipment much more fuel efficient than in years past, but the methods used to repair existing roads are also eco-friendly.  (Note: the Caterpillar Rotary Mixer RM-500 is shown above because I have classmates that work for Cat and huge equipment is, well, it's just cool.)  I am referring to an old technique that is gaining new found attention, ROAD RECYCLING, sometimes referred to as road reclaiming.

Road recycling utilizes the existing road material to build the new road (over the same road bed and rights-of-way).  When done properly, the technique of Full Depth Reclamation (FDR) uses 100% of the old road.  That means no waste to be hauled away, fewer diesel-belching off-highway construction vehicles, and fewer chips on your windshield.  Check out the following graph for potential savings.


The process is pretty simple and straightforward.  Heavy equipment, like the RM-500 shown above, pulverizes and mixes the old pavement and road bed.  During the pulverizing, water or stabilizing agents such as cement are added to the old material.  The result of the pulverizing and mixing is a suitable material for a stable foundation that can be shaped, graded, and compacted into a new road bed.  The final step is a new pavement layer made of chip-seal, asphalt, or cement.  Although that means there is energy and materials in order to supply new raw materials for the pavement layer, it also means that all of those used tires can still be chopped up and used for a quiet driving surface instead of tossed into landfills.

I, for one, am pleased to see this old idea breeding new life into our roads.  We can carpool, take public transportation, or buy hybrid vehicles all we want to help save the environment, but the truth of the matter is we still need roads to ride on.  I like my roads pot-hole free and that means road construction.  Finding GREEN methods to repair or replace existing roads deserves just as much attention as the vehicles that ride them.  I think Captain Planet would be proud.

Information for this post provided by RoadRecycling.org and American Road Reclaimers.
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