EHRA was selected as one of two firms to provide professional surveying services under contract to Houston Community College System.
EHRA conducted a traffic engineering study to identify the impacts of a proposed master development located near the intersection of FM 1488 and Peoples Road in the City of Conroe.
On-going surveying for property acquisition and engineering design surveys of re-routing of Buffalo Bayou north of downtown Houston between North Main Street and McKee Street. Services to be provided include “soundings” for Buffalo and White Oak Bayous.
Identified as a top priority during the development of the District’s Parks Master Plan, this portion of trail was the first phase of over two miles of planned trails to provide connectivity and recreation for District residents.
Identified as a top priority during the development of the District’s Parks Master Plan, this portion of trail was the first phase of over two miles of planned trails to provide connectivity and recreation for District residents.
Rice University engineers have developed a composite binder made primarily of fly ash, a byproduct of coal-fired power plants, that can replace Portland cement in concrete. The material is cementless and environmentally friendly, according to Rice materials scientist Rouzbeh Shahsavari, who developed it with graduate student Sung Hoon Hwang. Fly ash binder does not require the high-temperature processing of Portland cement, yet tests showed it has the same compressive strength after seven days of curing. It also requires only a small fraction of the sodium-based activation chemicals used to harden Portland cement.
The results are reported in the Journal of the American Ceramic Society.
More than 20 billion tons of concrete are produced around the world every year in a manufacturing process that contributes 5 to 10 percent of carbon dioxide to global emissions, surpassed only by transportation and energy as the largest producers of the greenhouse gas. Manufacturers often use a small amount of silicon- and aluminum-rich fly ash as a supplement to Portland cement in concrete. "The industry typically mixes 5 to 20 percent fly ash into cement to make it green, but a significant portion of the mix is still cement," said Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering. Previous attempts to entirely replace Portland cement with a fly ash compound required large amounts of expensive sodium-based activators that negate the environmental benefits, he said. "And in the end it was more expensive than cement," he said. The researchers used Taguchi analysis, a statistical method developed to narrow the large phase space -- all the possible states -- of a chemical composition, followed by computational optimization to identify the best mixing strategies. This greatly improved the structural and mechanical qualities of the synthesized composites, Shahsavari said, and led to an optimal balance of calcium-rich fly ash, nanosilica and calcium oxide with less than 5 percent of a sodium-based activator.
Source: Rice University/Science Daily