عنوان مقاله [English]
Soil pollution by hydrocarbon is a significant Geo-Environmental problem that can affect the environmental quality of soil, groundwater and air. Some physical properties of the soil such as stress, bearing capacity, permeability, etc., have changed due to entry of this contamination. On the other hand, requirement of appropriate soil is increasing due to development of urbanization and construction in recent decades. Sometimes a project must be founded at a site with hydrocarbon-contaminated soil, and providing appropriate soil may be difficult, due to economic or environmental issues, so stabilization of the contaminated soil is an appropriate method to treat the soil and change contaminated-soil into a useable material. Researchers have different opinions about the ability of stabilization of hydrocarbon-contaminated soil with cement: for example, some researchers believe that the cement cannot stabilize the hydrocarbon-contaminated soil. They consider that the particles of contamination cover the surface of cement and decrease its efficiency of stabilization. In the current research, the effect of adding cement to the contaminated clay soil with Anthracene is investigated. Anthracene is a representative of one group of hydrocarbon, called PAHs (Polycyclic Aromatic Hydrocarbons). PAHs are created due to incomplete combustion of fossil fuels or wastes. In order to investigate the effect of cement on the stabilization of clay contaminated soil with Anthracene, the specimens of natural clay soil, contaminated soil with Anthracene, soil-cement and Anthracene-contaminated that is stabilized with different percentage of cement (5, 10, 15, 20 and 30%) in different curing times (3, 7, 14 and 28 days) were prepared by static compaction method at maximum dry density and optimum moisture. Unconfined compressive strength (UCS) tests were conducted on the specimens. The results of the experimental work showed that adding Anthracene to clay soil, changes the compaction parameters; for example, the dry-specific weight of soil is reduced and the optimum water content is increased. Although adding cement to the Anthracene-contaminated soil improves the compaction of soil, it increases the dry-specific weight and reduces the optimum water content. In addition, adding the Anthracene also changes the unconfined compressive strength of soil, and it reduces strength of soil. Although adding cement increases the strength of the contaminated soil, the amount of increase in the strength depends on the percent of cement and curing time. Scanning electronic microscopy also is done on the natural soil, contaminated soil with cement, soil-cement and contaminated soil with Anthracene that is stabilized with cement with 10 and 20 percent of cement with 28 days of curing time. The results indicate that adding the Anthracene to the soil changes its structure to flocculated shape, but the decreasing of friction between soil particles due to adding Anthracene, leads the soil particles to moving easily together. Moreover, the results of this research show that the cement can stabilize contaminated soil with Antracene.