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Contractors have been the main risk bearers in most road construction and maintenance projects, especially when they are working under higher-risk delivery systems such as Performance Based Contracts (PBC), where the contractors are more likely to be responsible for both the construction and maintenance of the road for a certain warranty period. This research identified and analyzed the risks that the contractor is subject to under PBCs for hot mix asphalt (HMA) road construction and maintenance projects. The study used a mixed methods research design and was divided into three phases. In the first phase, employing a detailed literature review along with industry interviews, twenty-nine risks were identified in the construction and maintenance phases. In the second phase, risk severity rankings were calculated using probability and impact data that was collected from several contractors and a state agency. In the final phase, a correlation analysis was conducted. The results of this analysis will enable c...

The use of porous pavement allows water to drain into an aggregate storage layer beneath the pavement for temporary storage as it percolates into the aquifer below. When using this system in a parking lot application, the need for curb and gutter to channel the stormwater into a nearby retention basin is eliminated, as is the retention basin itself. An initial analysis of the porous system appears to solve some of the environmental issues related to stormwater runoff and aquifer recharge. However, these systems have not been evaluated using both life-cycle cost and life-cycle assessment to fully understand the costs and environmental implications of choosing one system over another. A case study was used to compare the two asphalt systems in a large parking lot application. The results show that the conventional asphalt system is both more cost effective and environmentally benign. The emissions area identified as having the greatest CO2 impact is the manufacturing/mining and extraction of aggregates maki...

While the structural steel industry has made commendable progress to improve its efficiency and reduce its environmental impacts over the years, room remains for improvement, particularly in the fabrication and erection of structural steel during construction. The purpose of this research is to determine the potential benefits of including the steel fabricator and erector early in the design phase with respect to increasing the efficiency and thus reducing the environmental impacts of the structural steel construction process. Interviews were performed with the key participants in the National Renewable Energy Laboratory (NREL) Research Support Facility (RSF) project located in Golden, Colorado, United States to collect information in the form of lessons learned. Analysis revealed several benefits that result from leveraging the unique perspective and knowledge of the steel fabricator and erector during the design phase when utilizing them for decisions concerning fastening hardware, types of connections,...

To support population growth, a viable fresh water supply, supporting water and wastewater treatment infrastructure, and electric capacity is needed. Historically the answer to growing demand was to build more reservoirs, however; viable potential sites are not plentiful. In addition, infrastructure for water supply and treatment is difficult, expensive, and time-consuming to develop. Greywater use offers the opportunity to stretch our water supply and electrical capacity through dual water use and less treatment. Greywater may offer a viable solution to increasing water supplies in the near term as we plan and development new water resources. This research identifies the potential impacts of greywater toilets on a large scale in two communities that are considering building additional water storage capacity. The use of greywater toilet systems in new and existing homes in these communities could potentially support new residential growth for 3.4 years in these areas. This could reduce the pressure on the...