It shouldn’t come as a total shock that a roadway surface constructed of permeable concrete materials would be designed and built in one of the country’s most progressive, environmentally conscious cities.
Someplace like, say, Berkeley, California.
Here, where fans of Donald Trump are about as common as rain in July, a portion of a city street named Allston Way was rebuilt using Eco-Priora pavers from Pavestone. The existing asphalt street surface was replaced with this permeable interlocking pavement roadway.
The pavers feature a patented interlocking joint and a micro-chamfered top edge profile. The joint profile allows surface water to infiltrate into the pavement and its sublayers, Pavestone says.
The pavers deliver average initial flow rates of 100 inches per hour, the company says, meaning that even with a clogging factor taken into account, the pavement will meet most stormwater management plans.
We won’t go into all the details about the workings of this permeable paved surface – more information is available at the Eco-Priora link above. But the company says a range of uses is possible, including courtyards, pedestrian malls, driveways, plazas, pool decks and many other installations.
For the Berkeley project, concerns about the excavation – including the effect on adjacent trees and presence of utility lines – were addressed by reducing the excavation depth by about a foot by installing an 8-inch layer of high-density polyethylene cellular confinement filled with an aggregate as part of the subbase.
A system of berms and subdrains within the pavement manages water entering the pavement, maximizing infiltration into the subgrade, according to a description of the project from Pavestone.
The project designers are AECOM and Applied Research Associates Inc., with installation provided by European Paving Designs, San Jose, California.
As for visuals, custom yellow and white pavers were installed in the Berkeley project, creating a contrast with the darker reddish-orange and charcoal pavers. Thus, driving lanes, pedestrian crossings and other required roadway markings are permanent and don’t require restriping, Pavestone says.
An initial stormwater monitoring report showed a 94 percent reduction in runoff during a storm that produced 1.75 inches of rain over a 19-hour period, the project description says.
Randy Hays, CEO of European Paving Designs, noted the project’s fit with the sustainable-construction priorities of Berkeley.
“Building streets that actually return water to an underground system is a pretty cool thing,” Hays says.
Indeed, sustainable is cool in this green-leaning burg.
A perfectly logical response when one comes across news of a redesign of a thermal bath facility in Bad Staffelstein, Germany. Krieger Architekten Ingenieure (Architecture Engineering), Velbert, Germany, used translucent concrete panels to impart color and create a “luminous salt crystal that seems to jut out of the water,” reports Architizer.
The structure is part of an upgrade of the bath hall, located in a natural cave and fed by the largest hot saltwater spring in Bavaria. Krieger Architecture opted to add a design element this part of the baths with the translucent crystal concept.
The crystal structure is composed of LUCEM, a concrete material that resembles stone slabs, but is transformed with LED lighting and fiber optics embedded in the concrete. Marine-grade steel for the structure’s framing was galvanized and coated to provide resistance to the high-salt environment.
3M digs potential pozzolan product
Fly ash from burning coal at power-generation plants is a common ingredient in concrete mixtures, where it functions as a pozzolan to enhance concrete durability.
Problem is, less burning of coal means less fly ash and, thus, less pozzolan of this type for concrete. And environmental concerns have certainly had an impact on coal burning. Chances are this trend will continue.
3M Co. believes it may have a solution to help make up the difference: natural pozzolans derived from volcanic rock.
The company has been at work formulating various iterations of a mineral-derived pozzolan for the past three years or so, and recently put a concrete mix incorporating this “supplemental cementitious material” to the test as a road pavement. The SCM is based on the kind of mineral that 3M extracts and processes to make granules for roof shingles.
In a recent test project at 3M’s Corona, California, facility, several concrete slabs were placed, using conventional fly ash as a pozzolan, and also with varying mixtures of the new mineral-based, natural pozzolan. Results were positive in terms of psi strength gain, surpassing the 4,000 psi in 42 days that Caltrans (California Department of Transportation) sets as a minimum psi level.
Jay Lukkarila, 3M mining engineer, said the new mix designs using the mineral-based pozzolan “will most likely reach that minimum strength in less than 28 days.”
The research project is ongoing and is still in “the early stages of development and business review,” a 3M spokeswoman tells this news bureau.
The technical leads for the natural pozzolans project are Lukkarila and John Edwards, 3M advanced product development specialist. No timetable is being given at this point on potential commercialization.
Disclaimer: The statements and opinions expressed in this blog post are those of the author or authors and do not necessarily reflect the position or opinion of Concrete Decor magazine.