Sustainable Land Development Today - November/December 2007 - (Page 8) YOUR VOICE The Readers Respond Soaking Up Attention (Porous Pavements) December 2007 does not happen to in-place pavements during hot I am writing in response to the article weather. If the article is in your June 2007 issue titled “Soaking referring to potential Up Attention: Stormwater management “draindown” of the professionals are starting to utilize the binder during the convarious forms of porous pavements as struction process, this is innovative solutions.” I would like to set easily corrected through the record straight for your readers. appropriate mix design First, some background about porous and possible use of fibers and modifiers. asphalt. The Franklin Institute, a scientifWe know of no examples of pavements, ic organization in Philadelphia, even very early ones, where this has hapPennsylvania, pioneered permeable pened, nor does the article cite any. pavements in the U.S. in the 1970s. Their A reader of the article might not realize first porous pavement designs were conthat porous asphalt is by far the dominant structed out of asphalt. One of the earliest type of permeable pavement. All across was built in 1977 at the Walden Pond the U.S., there are many more permeable State Reservation in Massachusetts. No parking lots that are asphalt than any special maintenance has been performed other pavement type, and they can be on that pavement in the 30 years it has found in all types of climates, ranging served the visitor center. Despite many from Minnesota to Arizona to Alabama. freeze-thaw cycles each winter, and And, the largest permeable pavement despite heavy use by buses and other facility we know of – 35 acres at the Port vehicles, that parking lot is still performof Portland, Oregon – is porous asphalt. ing well. Reasons for this marketplace domiIt is true, as the article says, that the nance include cost-effectiveness and ease asphalt industry has “made some good of construction. Porous asphalt is by far improvements in their porous asphalt the least expensive type of permeable product” since the 1970s. Our industry is pavement. Porous asphalt is far simpler dedicated to continuous improvement in to install than other pervious pavements. our products and processes. Through Because of the complexity of installing research at the National Center for pervious concrete pavements, it has been Asphalt Technology and elsewhere, we necessary to qualify the people who conhave continued to expand the knowledge struct them in order to avoid issues such base and improve technology. Today’s as over-finishing or over-consolidating porous asphalt pavements are better than the concrete surface to ensure permeabilever – and the earliest ones performed ity. Open-graded asphalt does not have very well. these issues, and it can be produced by The article alleges that the performany asphalt plant and installed by any ance of porous asphalt may be comprocompetent paving contractor. mised by the asphalt cement being mobiFar from taking our marketplace domlized by heat, draining down into the inance for granted, the asphalt industry base, and clogging the pavement. This has engaged in educational programs to spread the word about the benefits of permeable pavements to stormwater managers, developers, government agencies, and others. The National Asphalt Pavement Association (NAPA) has published a design guide, conducted workshops, and published articles on porous asphalt. With help from the Asphalt Pavement Alliance and our partners at the state asphalt pavement associations, we exhibit at trade shows and advertise in the relevant trade publications. Today we continue our educational activities. These efforts are bearing fruit in new applications for porous asphalt all over the country. Examples include the roads in the Pringle Creek Community in Salem, Oregon, where porous pavements are just one of the many green building strategies used. In addition, porous asphalt has been used for alleys in Chicago, Illinois, parking lanes in Indiana, and other non-parking-lot uses. We very much appreciate your magazine’s efforts to educate your readers about porous pavements. Such pavements are an excellent tool for managing stormwater in a sustainable way. They can promote infiltration, improve water quality, enhance site design, and decrease costs for developers and owners. For all the reasons discussed above, asphalt is the pavement of choice for porous installations, and NAPA is proud to have led the way to more widespread implementation of this important technology. Very truely yours, Dave Newcomb, P.E., Ph.D., Vice President— Research and Technology National Asphalt Pavement Association Send us your 2¢! This section is dedicated to comments from our readers Reader responses to articles in Sustainable Land Development Today are encouraged and may be sent via mail or email (Editor@SLDTonline.com), or online through SLDTonline.com. Mailing address: Sustainable Land Development Today, Attention: Editor, 275 East 10th St. Suite 200, Dubuque, IA 52001 © Entire contents copyright 2007, Land Development Today, LLC. No portion of this publication may be reproduced in any form without written permission of the publisher. Views expressed by the bylined contributors do not necessarily represent the opinion of the publisher. 8 November/December 2007 Sustainable Land Development Today http://SLDTonline.com
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