

EHRA completed a site-specific planning and visioning study for the proposed 470-acre San Jacinto Boulevard District (SJBD) in Baytown, Texas.
Facilities requiring expansion were also common wall construction, and the EHRA team converted the facilities into aerobic digesters and sludge thickeners.
EHRA assisted with the district creation of Montgomery County Municipal Utility District No. 126 to accommodate a ±329 acre master planned community located in northern Montgomery County in the City of Conroe, south of League Line Road, west of Longmire Road, and adjacent to Lake Conroe.
This project was the second phase of parks implementation outlined in the District's Parks Master Plan, which was completed by EHRA in 2007. Utilizing the site of a recently demolished former wastewater treatment plant provided an opportunity to create a passive park space for District residents.
EHRA planners, hydrologists and landscape architects worked together to propose an alternative use for the space, re-developing the basin into an amenity pond. EHRA carefully selected native plant materials for both their ability to survive in the harsh conditions of the basin as well as providing filtration for improved storm water quality.
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