A trip to a greener Windy City leads through the city’s alleyways
The city of Chicago and the Chicago Dept. of Transportation (CDOT) will attempt to green an area of the city longer than the distance from Chicago to Las Vegas. The development of the new Green Alley Project includes three main initiatives: the repaving of Chicago's 1,900 miles of alleyways with permeable pavement, the use of high albedo pavement in sidewalks, and the use of energy-efficient da...
The city of Chicago and the Chicago Dept. of Transportation (CDOT) will attempt to green an area of the city longer than the distance from Chicago to Las Vegas.
The development of the new Green Alley Project includes three main initiatives: the repaving of Chicago’s 1,900 miles of alleyways with permeable pavement, the use of high albedo pavement in sidewalks, and the use of energy-efficient dark sky lighting. The repaving of alleys with permeable pavement will help water trickle down into the purifying aquifer and help recharge the city’s groundwater system. The high albedo pavement will reflect the sun’s heat during the summer months and reduce smog levels and the heat island effect. Finally, the implementation of energy-efficient dark sky lighting for streetlamps, which focuses light downward rather than a 360-degree sphere, will reduce light pollution within the city’s limits.
Storm water management, a reduced smog effect, and an elimination of flooding in the alleyways will be some of the effects in the early stages of the Green Alley Project. Chicago’s commitment to the advancement of green technology will help expand the uses and effects of these technologies in the future. The high albedo pavement used in the sidewalks will lower temperatures and reduce smog, resulting in an improved outdoor air quality around the building. The lower temperatures and improved air quality will eventually reduce the strain on a building’s HVAC system and help lower cooling costs, especially during the warmer months. In Europe, the acceptance of the more advanced photocatalysts or titanium dioxide concrete represents the future for the high albedo concrete in the city of Chicago. The titanium dioxide reacts with sunlight and absorbs UV light. Through the absorption of the UV light, the process enables a catalytic reaction to take place. The reaction destroys common pollutants from vehicle emissions, smog, and the heat island effect.
In Chicago, the source of water remains Lake Michigan, but the source is not limitless and the search for more sustainable water and plumbing systems continues. The depletion of groundwater systems can lead to the addition of groundwater replenishment systems, similar to the systems in California, Colorado, and Florida, which purify sewer water to help replenish lowered levels of groundwater. Greater acceptance and an expanded use of permeable pavement in Chicago will result in a recharging of groundwater systems and may result in a wide scale redesign of plumbing and a more sustainable water system.
CDOT collaborated with S.T.A.T.E. Testing LLC, to oversee the concrete quality and control aspect of the Green Alley Project. Both CDOT and S.T.A.T.E Testing have discussed the benefits and future possibilities of such green technologies.
Jay Behnke, PE, president of S.T.A.T.E. Testing said, “There has yet to be any talks of using the high albedo concrete in driveways and parking lots in subdivisions and office buildings. The strength has increased, the technology is advancing, and the cost is going down; there is no foreseeable reason why driveways and sidewalks all over the Chicagoland area should not be using this technology.”
Behnke said the expanded use of these green technologies would influence the future of conceptual design and USGBC LEED certification processes. The age of the construction of mega-high rises should usher in new LEED standards. The inclusion of permeable pavement and high albedo concrete in the construction of the parking lots, sidewalks, and foundations should factor into the green building equation.
By Patrick Lynch, Editorial Intern