While few places if any get that much rain, this fact points to the rate of rainfall that travels through a pervious concrete pavement. Engineers use this to account for the inevitable dirt and debris over time, and when accepting runoff from adjacent impervious surfaces. The capacity design factors for pervious paving and permeable paver systems are the soil infiltration rates and the storage capacity in the underlying gravel base. Have a qualified civil engineer calculate the design capacity required for an individual site.
63 years after placement, part of Interstate 10 in California still carries over 240,000 vehicles a day.
Interstate 10 west of Los Angeles was
constructed in 1946 as part of US Route 66. The surface has been maintained (a
process called grinding) to maintain drivability, but that is still an
impressive record of service. Grinding was undertaken 19 years after it was
built to correct joint faulting and spalling. This was the first continuous
grinding project in North America. It was
ground two more times; once in 1984 and again in 1997. The concrete highway is
63 years old and still giving drivers their kicks.
Each year the cement industry uses enough industrial by-products to fill a freight train 386 miles long.
Burning coal creates fly-ash, bottom ash, and synthetic gypsum, much of which was previously land-filled. All of these, along with mill scale and slag, by-products from steel production, and spent foundry sands and sandblasting grit can be used by cement manufactures as an component of Portland cement. Concrete structures used over 23 million tons-- approx 13 million cubic yards -- of fly ash, slag and silica fume as Supplemental Cementing Materials (SCMs) in 2007. Stacked on a football field, this amount would be about 1.4 miles high!
Set side to side, the tires consumed as fuel by the cement industry each year would cross the country almost three times.
Tires have been a tough nut in the waste management industry. Some creative uses for reclaimed rubber, such as flooring products, have emerged, but there hasn’t been a significant market created to absorb the huge number of tires discarded every year. The U.S. generates over 300 million scrap tires annually (that would be 18 cross-country rows), and cement manufacturers were able to use 58 million. They have 25% more energy than the coal they replace and the steel belts, a problem for most recyclers, are a required ingredient for cement production. Land-filled tires can burn out of control because of their energy content and open burning releases noxious emissions. Controlled, high-temperature burning destroys pollutants and displaces fossil fuel consumption.
That saves a lot of landfill space and virgin materials; better to use it to fill occupied space. While it lasts a long time, at the end of its service life concrete can be crushed and used again, either as fill or as aggregate in new concrete. This is growing as more areas and more producers gain familiarity with the resource and the best ways to reuse it. Even the reinforcing steel can be reclaimed and recycled.
Over 70% of the world’s population lives in concrete structures, so perhaps that fact isn’t so surprising, but it does put a little perspective on the five percent of global CO2 emissions attributed to the cement industry.
The average distance in the U.S. between a ready-mixed concrete plant and a project site is only 14.2 miles.
Concrete is one of the most localized material productions out there. Food is often shipped farther; consumer goods, definitely; wood products, depends where you are. Cement is frequently manufactured in the region, aggregate comes from within 50 miles in most cases. Water is local, and increasingly the industry is using reclaimed water. All this keeps transportation energy use down and contributes to local jobs.
Source: Concrete Joint Sustainability Initiative - www.sustainableconcrete.org