Abstract: Loess has poor water stability. It will disintegrate, when encounters water, and cause instability of the building foundations in loess area. The application of lignosulfonate for loess reinforcement and related engineering properties are evaluated by experimental program including unconfined compressive strength test, disintegration test, uniaxial tension test, triaxial compression test and permeability test. The test results indicate that calcium lignosulfonate improves engineering properties of loess rather than sodium lignosulfonate. Compression and tensile strength of the stabilized soil firstly increase and then decrease as the content of calcium lignosulfonate increases. Less moisture content generates greater the density and greater strength of the solidified soil. The strength of strengthened soil increases firstly and then stabilizes as the growth of curing age. Calcium lignosulfonate presents favorable reduction on loess disintegration and penetrability. The research concludes that calcium lignosulfonate can significantly improve the engineering properties of loess. The suitable addition amount of calcium lignosulfonate should be 1.0% and the curing age should be 7 days. The scanning electron microscope analysis assists the further discussion on two mechanisms for the improvement of engineering characteristics of loess by calcium lignosulfonate: soil particles cementing and pore filling.

Key words: loess, lignosulfonate, properties of stabilized soil, stabilization mechanism