2022 Volume 32 Issue S Pages 159-163
Salt-affected soils are widespread in countries with arid and semiarid regions, and a decrease in agricultural production due to excessive salts is a very serious problem. In China, salt-affected soil amelioration with flue gas desulfurization gypsum (FGDG) has been performed. Otherwise, the accelerating urbanization has led to a large number of demolitions of infrastructures in China. Therefore, the need for the recycling and reuse of not only desulfurization gypsum but also waste concrete is a pressing issue. In this study, changes in physicochemical properties in the salt-affected soil amelioration with FGDG, cement fine powder (CFP) and waste concrete particle (WCP) were reported. Two high ESP soils in Yinchuan, China was used in the soil amelioration test. The CFP and WCPs in different particle diameters based on 1.0 wt% application rate of wet FGDG (W-FGDG) were added to the soil. Soil chemical properties (pH, EC, and ESP) before and after mixing with soil amendments were measured, and their properties were evaluated after 3 weeks and 6 weeks. Consequently, soil EC and ESP decreased drastically in all application tests, but soil pH in CFP and WCPs took a high value. And pH, EC, and ESP after 6 weeks took almost the same value immediately after amelioration. WCPs smaller than 2.0 mm could ameliorate a high ESP soil at a smaller amount of amendment compared to larger WCP. In addition, the increase in hydraulic conductivity due to waste concrete application could be confirmed. These results indicated the effectiveness of waste concrete as salt-affected soil amendments.
