Characteristics And Utilization Of Roadbed Soft Soil Improved With The Desulfurized Fly Ash In Construction Highway

With the fast development of the railways construction, how to deal with the highway soft ground has been paying more and more attention by the country, the government and the researchers. Now, fly ash mixed with limestone or cement as addictive stuff has been used mostly in our country to improve the stabilization of the roadbed and the pavement base. With the sustainable development of the economy and the requirement of environment protection, the desulfuration technology has been adopted in internal power stations to deal with S in coal combustion to reduce the atmospheric pollution of SO₂. The desulfurized fly ash produced by desulfuration process in Coal Burning Power Plant has greater performance difference between common fly ash ,and the study in the treatment of soft roadbed stabilization is less, how the desulfurized fly ash improved the strength of the soft soil will be studied and analyzed in this paper though laboratory experiments .There are many differences between the desulfurized fly ash and fly ash at physical and chemistry properties, this paper will mix the silt-clay and loam general exist in Middle and Lower Yangtze River with proportions of the desulfurized fly ash, analysis the effect and mechanism of how the desulfurized fly ash improved the strength of the soft soil though laboratory tests. Major achievements of this paper are as follow:1) The physical parameters of the desulfurized fly ash are summarized and analyzed, like: density, fineness, water requirement ratio and the chemical composition differences between the desulfurized fly ash and fly ash, the chemical parameters of the desulfurized fly ash are studied, like :ignition loss, carbon content, pozzolanic activity, the influencing factors of pozzolanic activity are analyzed.2) Test scheme is designed, though laboratory experiments with silt-clay and loam, the optimum ratio and optimum water content of the two soft soils mixed with the desulfurized fly ash and limestone are achieved. With different mixed ratios, the differences between strength and the regulations of the strength when condensation and retardation are analyzed.3) Mixed silt-clay and loam with different ratios of the desulfurized fly ash, the CBR and elastic modulus were gained, the change ratio of the desulfurized fly ash and the regulation of testing data were analyzed.4) The mechanism how the desulfurized fly ash improved the strength of the soft soil was analyzed , how the property of the volcanic ash, self-harden, ion exchange improved the strength of the soft soil were detailed, and the strength regulation at different conditions were primary researched.