Pavement sustainability optimization using quarry by-products and geosynthetics

Sustainability;Pavement;Quarry By-Products;Geosynthetics;Geotextile

Mwumvaneza, Vincent

关键词: Sustainability;    Pavement;    Quarry By-Products;    Geosynthetics;    Geotextile;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/78516/MWUMVANEZA-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Sustainability has become a major concern in the construction industry, especially highway construction. In the U.S, significant effort is being exerted to quantify the environmental emissions associated with construction and production of materials used in pavement construction. The increased aggregate demand by the construction industry has resulted in increased production of quarry by-products (QB) and overall energy consumption because of the production of aggregates. The use of geosynthetics and QB in unbound material pavement applications can mitigate the high demand for natural aggregates, thus reducing the depletion of natural aggregates, environmental emissions, and energy consumption caused by stockpiling of QB and aggregate production. The use of geosynthetics at the subgrade/base interface has been adopted by many states in the U.S, and design standards have shown that this particular application results in a reduction of aggregate base thickness or increase the pavement service life; however, limited studies have been conducted to assess the environmental impacts caused by the production and use of geosynthetics in pavement applications. While the use of QB in pavement applications can reduce the consumption of natural aggregates and, consequently, all associated environmental burdens, there are no developed guidelines and specifications on using QB in these applications. A pilot study intended to develop specifications and guidelines for the use of QB and assess the environmental impacts of pavement materials was conducted at the University of Illinois at Urbana-Champaign (UIUC). A detailed laboratory study was conducted to characterize the engineering properties of QB materials, produced in the primary, secondary, and tertiary aggregate production stages. The results show that the unconfined compressive strength of QB materials is very low, and chemical admixtures, such as Portland cement and Class “C” fly ash, were used to improve the strength properties of QB materials. In general, treated QB materials were 10 to 30 times stronger than the virgin QB samples. Such significant increases in the strength of stabilized QB materials may indicate suitability of QB for sustainable pavement applications. Under a similar study, the environmental impacts of using geosynthetics in pavement were assessed. The results show that that the use of geosynthetics in pavement may reduce environmental emissions by 6.5%, and total energy by 2.7% compared with conventional pavements.