2.2. Methods
2.2.1. Pavement placement procedures
All three pavements were placed on top of crushed stone base that had been prepared ahead of time. Concrete was delivered to the site in front discharge transit trucks. Each truck contained approximately 3.8 m3 for Projects A and C and approximately 5.4 m3 for Project B. The concrete was discharged from the chute in an arc as the truck backed up over the stone base. The workers moved the mix with come-alongs as needed, but not to excess. The crew then used a hydraulic roller screed that spun in the opposite direction than it was pulled. Following the screed, the fresh concrete was cross-rolled using a 1 m long roller having a 150 mm diameter. As placement progressed, transverse joints were formed with a rolling joint cutter every 3.5–4.5 m depending on the pavement configuration. Additionally, after the fresh concrete was screeded to the proper grade, the fresh concrete was sprayed with soy bean oil to aid curing and act as a sealer. Finally, the finished concrete was immediately covered with plastic for 7 days for curing purposes.
2.2.2. Specimen preparation (cylinders and slabs)
During placement of the pervious concrete pavements, 150 mm diameter by 300 mm tall cylinders were cast for all three projects. Concrete was sampled from at least two trucks from each project to make cylinders. Cylinders were prepared using different consolidation techniques in an effort to identify methods that would best replicate the properties of in-place pervious concrete. To this end, eight different methods were evaluated as summarized in Table 3. These methods included the use of either a 15.9 mm diameter steel rod (standard tamping rod), a standard Proctor hammer (2.5 kg), and dropping the mold on a concrete surface from a height of 50 mm. After consolidation, the concrete was screeded flush with the mold and then a plastic cap was placed on the mold. The cylinders were placed on a level surface near the newly placed concrete where they remained undisturbed for 7 days.