The construction of the project, with the exclusion of the pavement installation, was competitively bid by our facilities group. The contractor selected for this portion of the work was Scott Construction. Scott commenced construction on 17 September 2007.
The contractor selected for the placement of the pervious concrete was Engelman Construction. This firm was recommended by Mr. Phil Kresge of the NRMCA. Mr. Kresge worked closely with Engelman Construction, a certified pervious concrete contractor, to develop a mix design and was present for the placement of the pavement. The pervious concrete was placed on 8 and 9 October 2007. A summary of the installation process is presented below:
The pervious concrete installation at Villanova University was carried out over two 4-hour days, with a 15’x50’ area being poured each day. The process began with setting up forms and spraying them with a diesel fuel lubricant. While the forms were being set up the stone bed was wetted thoroughly so that the concrete would not dry too quickly and crack after being laid. Once the gravel was soaked, the concrete was poured from a mixer to cover an approximately 15’x7’ area at a depth of 6”. A 3 person crew spread this concrete to approximately level using hand shovels and rakes. Next, another 3 person crew ran a 16’ long roller screed, lubricated with diesel fuel, over the poured area to level the concrete. Finally, a tarp was pulled over the finished area to prevent quick drying. This tarp must be placed over the finished area within 15 minutes of the concrete mix leaving the mixer to ensure successful results. This process was then repeated until the entire 15’x50’ area was poured and leveled. Two evenly spaced control joints were grooved in the fresh concrete across the 50’ dimension to allow for expansion of the concrete.
After the first half of the bed was poured, it was allowed to cure for one day before the second half of the bed was poured. This was to allow the first half to harden enough for the crew to walk and run the end of the roller screed over. At the completion of the two pours, the concrete was cured with the tarp still covering it for one week before it was open for traffic.
The contractor selected for the placement of the porous asphalt was Burkholder Pavement. This firm was recommended by Mr. Kent Hansen of NAPA. The mix design was created by Cahill Associates and is the same material placed at the Radnor Township Middle School in Wayne, PA (about 5 miles west of Villanova). The porous asphalt was placed on 1 October 2007.
The installation of the asphalt occurred in one day and took approximately three hours to complete. A team of five used standard asphalt equipment and procedures in the installation. The standard asphalt procedure uses an asphalt paver which can hold large quantities of the hot asphalt. This paver spreads a level strip of asphalt that is approximately eight feet in length. The depth of the asphalt was 2.5 inches. For the tight areas and the edges where the paver could be used the asphalt was placed by hand. Part of the standard installation procedure is using diesel fuel as a lubricant on the equipment to prevent the hot asphalt from sticking to the rakes and other pieces of equipment, and allowing for the even distribution of asphalt throughout the site. Consequently, the spraying of diesel fuel over the site was done quite frequently over the course of the installation. After the asphalt was laid a mechanical roller was used to compact the asphalt surface. The result of this compaction left some small areas where there is no visible pore space. These areas are small and sporadically spaced, and should not affect the overall performance of the asphalt surface.
Approximately two weeks after the completion of the asphalt installation a hot tar seal was applied to the edges of the asphalt site. This is to help prevent any spalling from occurring from the edges, and help strengthen the joint between the standard and porous asphalt. The hot tar seal covers no more then six inches of the porous asphalt.