Guan'gai paishui xuebao (Jun 2022)
Using Mixture of Industrial Waste Residues and Cement to Reinforce Channel Foundation in Salinized Soils
Abstract
【Objective】 Concrete channel slabs used in the Yellow River diversion irrigation channels in Yinbei Plain in Ningxia province are susceptible to frost swelling, corrosion and dissolution induced by soil salinity. Different mitigation techniques have been proposed and the purpose of this paper is to investigate the efficacy of reinforcing the channel foundation by mixture of cement and industrial residuals. 【Method】 The salinized soil in the foundation was reinforced by cement mixed with various industrial residuals at different ratios. Overall, there were three cement ratios (weight/weight): 2%, 4% and 6%, each being mixed with fly ash at ratio of 10%, 20% or 30%; silica fume at ratio of 1%, 3% or 5%, and desulfurization gypsum at ratio of 3%, 6% or 9%. For each reinforced specimen, we measured its strength using unconfined compressive test, and then analyzed its XRD, SEM and EDS images. 【Result】 The agents that affected the strength of the reinforced specimens most is ranked in the order of cement>silica ash>fly ash>desulfurization gypsum. The unconfined compressive strength of the reinforced soil was significantly higher than that of untreated soil specimens. Mixing 6% cement with 10% of fly ash, 6% of desulfurization gypsum and 5% of silica fume was optimal. Synergistic interaction between them promoted dissolution of silica and aluminum oxygen micro-lattice. In combination with Ca2+ in the soil, they generated C-S-H, C-A-H gels. These gels stacked with each other forming a spatial skeleton structure, increasing compressive strength of the specimen as a result. EDS energy spectrum analysis of morphology of the SEM images proved the composition of the mixture. 【Conclusion】 Reinforcing the salinized soil in channel foundation by mixing it with 10% of fly ash, 5% of silica fume, 6% of desulfurized gypsum and 6% of cement was optimal to solidify the soil.
Keywords
