To compare the engineering properties of different fly ash modified soil, pH, Atterberg limits and compaction properties were investigated in this study, and several performance indicators were compared, such as liquid limit, plastic limit, maximum dry density and optimum water content of Shanghai silty clay and heavy loam mixed with fly ash. The test results were as follows. The addition of fly ash improved pH of the silty clay and heavy loam. The liquid limit and plastic limit of two types of soil decreased with the increase of fly ash, the maximum reduction rate of silty clay was 7.1%, 4.9%, while the heavy loam was 5.8%, 2.4%. The influence of fly ash on liquid limit and plastic limit of silty clay was higher than that of heavy loam. The plasticity index and the maximum dry density were reduced, specifically, optimum water content of the silty clay increased with the fly ash added more, while heavy loam was the opposite. The experiment provided a useful reference for modification research of different soil textures and the rational utilization of fly ash.

engineering properties; fly ash; soil texture; modification