Chemical stability of aggregates under different types of soil

Using 4 different types of soil samples, the saturated hydraulic conductivity of soil was tested with falling head method by filling 0.25~5 mm soil aggregate dry screened in indoor and set with 1.40 g/cm3 bulk density in earth columns. The soil samples were immersed in five ammonium chloride solutions of different concentrations for 24, 48 and 72 h later respectively, which was used to discuss the reaction characteristics of different types of soil structural stabilities with saline solution as well as resistances to chemicals damage. The result indicated that the soil saturated hydraulic conductivity were not constant, and the saturated hydraulic conductivity of all 4 types of testing soil decreased significantly with the increasing of ammonium chloride concentration and soaking time. But different types of soil in response to salt solution were significantly different. The main conclusion was that not all water-stable soil aggregates owned stronger chemical stability, and the chemical stability of aggregates had relation with the type, quantity and quality of different cementing agents, especially had significant response to chemical substances in the soil solution.