Material Matters - Fall 2012 - (Page 26)

PROJECT SPOTLIGHT By Jeff Jones Quality Control Manager, Buffalo Redi-Mix Co. Exposed Aggregate Pervious Concrete IN APRIL, 2009, the Buffalo Olmsted Conservancy stated it would connect the Olmsted Park System with the Niagara River Greenway Trail via the Scajaquada Pathway. The Scajaquada Pathway is a multi-use trail parallel to Scajaquada Creek that provides an inland connection from Erie County Riverwalk to Delaware Park Lake. “Exposed aggregate concrete is the Olmsted standard for new sidewalk construction and would be considered generally compatible for new construction,” according to the Olmsted Parks Conservancy & Parkway System – Design Guidelines. The guidelines also state that “new construction should be as energy efficient and sustainable as possible.” It’s like they were asking for pervious concrete (PrvsC) before they even knew what it was. Buffalo’s Olmstead Park was the site of an early PrvsC demonstration piece, placed in 2009. The park loved the product but wanted to make it even more natural looking by exposing the aggregate on the surface. Greg Robinson, RLS, ASLA, the park’s landscape architect, was an early adopter of PrvsC for the park and made the final decision on which ready mix producer would provide the materials for this job. A special design by Buffalo Redi-Mix was selected. The mix consisted of graded washed round gravel that, when exposed, provided the desired natural look. This project overcame objections and concerns of our own industry to decorative PrvsC construction. As NYMaterials Vice President Greg Novitzki said, “Remember, we don’t sell it ‘cause it’s pretty, we sell it because we are going to save the earth.” Novitzki discouraged any thoughts of an “exposed aggregate” PrvsC as he was concerned of aggregate loss during the paste removal process. So we went ahead and proved him wrong. Two trial pads were constructed to prove and perfect the process. In the fall of 2011, Titan Development, PrvsC certified contractor since 2010, placed approximately 200 yards of PrvsC on the Jesse Kregal Pathway along the Scajaquada creek in Buffalo. On average two loads of concrete were placed each day, one in the morning and one in the afternoon. After each placement, surface retarder was applied and then covered with plastic. Twenty-four hours later, the surface was washed and broomed to remove the paste to give the concrete an exposed aggregate appearance. The objective was to give the path a natural gravel look. Conveyor trucks had to be used for the majority of the pours due to the limited accessibility of the walking path. The project was completed in 2011 and weathered the winter in fine shape. To look at the surface one would think they were walking on a gravel pathway subject to slipping and sliding particularly on the sloped sections. However, upon closer examination, the pervious provides a solid sound cohesive structure to hike and bike on. ● 26 Material Matters • Fall 2012

Table of Contents for the Digital Edition of Material Matters - Fall 2012

Breaking the Bottlenecks
Glacial Materials Goes Emerald Green
The System Works
Giving HMA Driveway Advice
Promotion Doesn’t Cost – It Pays
Exposed Aggregate Pervious Concrete
Stuyvesant Falls Hydroelectric Plant: Steel Fiber Reinforcement in Action By Dan Casale

Material Matters - Fall 2012