Search

This paper reports the results of an initial attempt of using iron ore tailings (IOTs) to develop greener engineered cementitious composites (ECCs). ECC is a unique class of high-performance fiber-reinforced cementitious composites featuring high tensile ductility and durability. However, the high cement usage in ECC limits the material greenness and increases the material cost compared with normal concrete. In this paper, IOTs in powder form are used to partially replace cement to enhance the environmental sustainability of ECC. Mechanical properties and material greenness of ECC containing various proportions of IOTs are investigated. The newly developed versions of ECC in this paper, with a cement content of , exhibit a tensile ductility of 2.3-3.3%, tensile strength of 5.1-6.0 MPa, and compressive strength of 46-57 MPa at 28 days. The replacement of cement with IOTs results in 10-32% reduction in energy consumption and 29-63% reduction in carbon dioxide emissions in green ECC compared with typical ECC. Thus, the feasibility of producing greener ECC with significantly reduced environmental impact using IOTs, and maintaining the mechanical properties of typical ECC, is experimentally demonstrated in this paper. [ABSTRACT FROM AUTHOR]

A novel approach to life-cycle sustainability (impact) assessment and interpretation procedure on the basis of multiple criteria is developed in this paper for the comparison and evaluation of alternative road pavement designs. A case study reported in the literature, which compared pavement structures with virgin materials as well as industrial by-products such as coal ash, crushed concrete waste, and granulated blast-furnace slag, was examined in the context of multicriteria decision analysis (MCDA) using the proposed approach. The environmental loadings assessed during the life cycle of the pavement structures included natural raw materials and secondary products, energy and fuel consumption, emissions of carbon dioxide (), nitrogen oxides (), sulphur dioxide (), volatile organic compounds (VOCs), carbon monoxide (CO) and particles, dust emissions, compounds leaching into the soil, and noise. The proposed qualitative decision approach to life cycle-based environmental impact assessment, similar to lexicographic methods in MCDA, relies purely on the qualitative relative importance preferences specified by the decision maker and logical inference. The decision procedure employs dominance testing using the aggregated relative importance preferences to identify which pavement design alternatives dominate the others. [ABSTRACT FROM AUTHOR]

Building regulations and governmental policies create pressure on the construction industry to minimize the environmental impacts that are caused by buildings. Achieving energy efficiency, and thereby low-carbon construction, is only possible by cooperation among the participants in the construction supply chain. Clients in particular have an important role in promoting environmental sustainability. In this paper, the carbon-reduction process is analyzed from a construction client's perspective. A framework is developed to analyze the interrelated components of this process, including the drivers, initiatives, challenges, facilitators, solutions, and achievements. A qualitative case study methodology was employed to gain a better understanding of the project-based practices and corporate policies in achieving energy efficiency. The study presents the results of three award-winning construction projects from the U.K. in which innovations for improving environmental sustainability were based on the Code for Sustainable Homes. The study outlines the initiatives and strategies of clients for carbon reduction, obstacles faced by project teams, mechanisms that helped overcome the difficulties, and low-carbon solutions applied to design, construction, and operation in the selected cases. Effective leadership, corporate responsibility, a focus on end users, repeatable nature of projects, and integrated teams are found to be the main success factors. The findings of this study are expected to guide construction professionals in implementing innovative low-carbon practices in collaborative project environments. The proposed framework can be used to better understand the carbon-reduction process in other projects and other countries where different regulations and conditions prevail. [ABSTRACT FROM AUTHOR]