Study on Structural Improvement of Loess by Waxy Rice Powder in Weak Acid Environment. Issue 3 (August 2020)

• Record Type: Journal Article
• Authors: Tang, Xiaowu; Yu, Yue; Fei, Minliang; Sun, Guoping; Zhao, Wenfang
• Is Part Of: IOP conference series. Volume 558:Issue 3(2020)
• Publication Date: 2020-08
• Subjects: Earth sciences -- Periodicals; Environmental sciences -- Congresses; Environmental sciences -- Periodicals; 550.5
• DOI: 10.1088/1755-1315/558/3/032018
• Languages: English
• ISSNs: 1755-1307

Abstract

Abstract: Waxy rice is widely used in many ancient buildings due to their good performance in some fields (such as caking property, impermeability, weatherability, etc.). In the humid environment of South China, the excavation of ancient sites is faced with many problems, especially for sites with deep burial depth, it is necessary to set support and minimize the impact on the site environment. In the excavation project of Jingtoushan site, located in the town of Sanqi, Yuyao, Zhejiang Province, China, the loess between the steel structures supports needs to be reinforced. Waxy rice, as a traditional Chinese building additive, was used as the reinforcement of this project. Therefore, it is of great significance to explore the best proportion of waxy rice powder mixed with loess. In this paper, the standard columns with different proportion of waxy rice powder were made, and the uniaxial compression tests were carried out after curing for 0~180 days in standard humid environment (25°C and 60% humidity). It was found that the soil columns with 2% waxy rice powder had the best improvement effect. Due to the weak acidity of groundwater in South China, loess specimens mixed with 0%, 1%, 2%, 3% waxy rice powder was soaked in acetic acid solutions of 0mol/L, 0.5mol/L, 1mol/L and 2mol/L respectively, and the consolidation fast shear test, SEM test and mercury injection test were completed. The results show that the overall structure of the specimen is improved when the concentration of acetic acid is low. Acetic acid dissolves the calcium carbonate in the loess-waxy rice structure, quickly and effectively destroys the poor pore structure in the loess, and makes the waxy rice powder filled as the binder between the soil particles, forming a new structure. The improved structure has strong shear strength. When the concentration of acetic acid is high, the cementitious substance between the soil particles dissolves and the pore content increases. The waxy rice powder is not enough to fill the extra pores. Therefore, it is suggested that the proportion of waxy rice powder should be more than 2% in the areas with strong acidity. The study provides a useful reference for the excavation and follow-up protection of earthen sites in the acid environment of South China.