Landscape Architect & Specifier News

AUG 2013

LASN is a photographically oriented, professional journal featuring topics of concern and state-of-the-art projects designed or influenced by registered Landscape Architects.

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Page 23 of 157

hardscapes news Smog-Eating Paver Results Prove Promising dutch researchers have found that pavers containing titanium dioxide – a common ingredient in sunscreen – can significantly reduce harmful airborne pollutants from vehicle emissions in urban areas. Photo: sCIeNCe dIReCt Findings published by the Eindhoven University of Technology in the Netherlands found that surfaces treated with a photocatalytic – an element that accelerates a chemical reaction when exposed to light – can substantially reduce airborne pollution on a normal city street. The university's experiment was conducted for one-year on two adjacent streets in Hengelo, eastern Netherlands. Researchers measured the air quality of a 100-meter stretch of standard pavement on one street against a 150-meter 'test street' of concrete pavement containing titanium oxide, a photocatalytic that removes pollutants like nitrogen oxide (NOx) from the air and converts them into inert nitrates. Secrets of Ancient Roman Concrete Both streets were measured for levels of NOx. The test street managed to reduce air pollution by up to nearly half (45 percent) in ideal weather conditions, and by nearly a fifth (19 percent) over an entire day. "This latest research shows the potential of chemically engineered surfaces to further improve our quality of life, especially in major urban areas where traffic emissions are high," said David Brown, chief executive at the Institution of Chemical Engineers. The full text of the study was published June 15 in the Journal of Hazardous Materials. Brick Maker CalStar Opens Second Miss. Plant Calstar's primary plant in Caledonia, Wis., produces bricks with recycled fly ash from a nearby power plant instead of traditional, kiln-fired methods, reducing emissions and energy costs with these sustainable manufacturing practices. REvEAlEd Researchers sampled a concrete breakwater built by ancient Romans in Pozzuoli Bay, near Naples, Italy, that dates back to around 37 B.C. Modern cement structures are typically designed to last about 100 years at best. CRedIt: UC BeRkeley/d. BaRtolI, CoURtesy of J.P. olesoN) A team of geologists and engineers has discovered a concrete breakwater in the Mediterranean Sea, constructed by the ancient Romans. It has endured for more than 2,000 years. The long-term durability of the structure could hold the keys to concrete production methods that could improve current construction and reduce emissions. "It's not that modern concrete isn't good. [In fact] it's so good we use 19 billion tons of it a year," said Paulo Monteiro, professor of civil and environmental engineering at the University of California, Berkeley, and research team leader. "The problem is that manufacturing Portland cement accounts for seven percent of the carbon dioxide that industry puts into the air." Monteiro's team found the Romans made 24 Landscape Architect and Specifier News their concrete with a mix of lime and volcanic rock baked at 1,652˚ Fahrenheit or lower, requiring far less fuel than present methods. In contrast, Portland cement, the "glue" that holds modern concrete together, uses a clay and limestone mix that 'cooks' at 2,642˚F. Analysis showed the Roman recipe needed less than 10 percent lime by weight, made at two-thirds or less the temperature required by Portland cement. The volcanic ash in the mortar mix also creates a more stable bonding compound than Portland cement, producing the longevity of structures like the Pozzuoli Bay breakwater. The researchers' findings were published in the Journal of the American Ceramic Society on May 28, and additional results will appear in the October issue of American Mineralogist. Wisconsin-based masonry firm CalStar Products announced plans to open a second manufacturing plant in Columbus, Miss., in early 2014. The plant will create at least 58 jobs over the next three years. The Columbus plant will produce the firm's full line of bricks, pavers and thruwall units, and will expand trim and accent capabilities with an automated cast stone production line. Michael Telischak, CalStar's vice president for manufacturing, said the Columbus location would allow the company to reduce freight costs for Southern customers and meet growing demand.

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