Sulfate transport assessment of cementitious materials-solidified saline soil

Abstract

Subgrade is an essential factor for the service life of highways and railways, especially the sulfate attack of subgrade made of saline soil. Therefore, it is necessary to improve the transport property of subgrade. In this study, sulfate transport of cementitious materials-solidified saline soil was assessed. Firstly, factors affecting sulfate transport were characterized in natural soil. Furthermore, fly ash and lime were implemented to prepare a new kind of improved soil. By analyzing the microstructure development, influence of fly ash and lime on sulfate transport was investigated and the improved mix proportion was addressed. Finally, the last section focused on the mechanism for sulfate resistance of the soil. Raw materials, phase assemblage improvement, and pore structure refinement caused by filler effect and pozzolanic reaction effect of fly ash were the main reasons for the sulfate resistance increase. This study is helpful for the service life improvement of highways and railways.

Keywords:

• solidified saline soil
• sulfate transport
• fly ash
• pore structure
• pozzolanic reaction

Additional information

Funding

The study was funded by the National Natural Science Foundation of China Joint Fund for regional innovation and development (U21A20150), National Postdoctoral Program for Innovative Talents (BX2021065), the National Natural Science Foundation of China (No. 52108225), the Open Research Fund of Jiangsu Key Laboratory of Construction Materials, Southeast University (202202), the State Key Laboratory of High Performance Civil Engineering Materials (2020CEM001), and the Science and Technology Research Project of China Railway (2020YY240610 and K2020G033). The authors are greatly thankful for the support.