Journal Published Online: 30 September 2021
Volume 50, Issue 6

Effect of Superhydrophobic Nano-SiO on the Geotechnical Characteristics of Expansive Soil

CODEN: JTEVAB

Abstract

The application of an environmentally friendly modifier-superhydrophobic nano-silicon dioxide (SiO2) on improving the geotechnical characteristics of expansive soil is explored to examine the effect of different percentages of superhydrophobic nano-SiO2 (0.2 %, 0.4 %, 0.6 %, 0.8 %, and 1.0 % by weight of the parent soil) on soil expansion, shrinkage, permeability, and unconfined compressive strength (UCS). Two types of samples, unmodified soil (without nano-SiO2) and modified soil (with nano-SiO2), were used. Results revealed that the shrinkage rate, the Expansion rate, and permeability decreased for the soil samples modified with different contents of superhydrophobic nano-SiO2 and the UCS increased. The shrinkage rate decreased from 3.8 to 2.2 %. The minimum expansion rate of the soil samples modified with superhydrophobic nano-SiO2 was a quarter of that of the unmodified soil. Permeability decreased gradually from 1.38 × 10−8 cm/s to 6.25 × 10−10 cm/s as the superhydrophobic nano-SiO2 content increased. The peak UCS (647 kPa) of modified soil increased by almost 212 % compared with that of the unmodified soil. Superhydrophobic nano-SiO2 helped improve the geotechnical characteristics of expansive soil. In the shrinkage and unconfined compressive tests, 0.6 % nano-SiO2 content had a better effect on the modified soil. In the unloaded expansion and permeability test, the expansion rate and permeability decreased as the nano-SiO2 content increased. After the nano-SiO2 content reached 0.6 %, the decreasing speed became slow. The expansion rate and permeability were similar when the nano-SiO2 contents were 0.6 %, 0.8 %, and 1.0 %, respectively. Therefore, the optimum superhydrophobic nano-SiO2 content was 0.6 %.

Author Information

Luo, Xiaoqian
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, China University of Chinese Academy of Sciences, Beijing, China
Kong, Lingwei
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, China
Bai, Wei
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, China
Jian, Tao
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei, China University of Chinese Academy of Sciences, Beijing, China
Pages: 16
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Stock #: JTE20210026
ISSN: 0090-3973
DOI: 10.1520/JTE20210026