@article{liu_montoya_2022, title={Effects of microbially induced carbonate precipitation on diffuse double layer and particle fabric of oil sands fine tailings}, volume={49}, ISSN={0315-1468 1208-6029}, url={http://dx.doi.org/10.1139/cjce-2021-0240}, DOI={10.1139/cjce-2021-0240}, abstractNote={ Microbially induced carbonate precipitation (MICP) is a sustainable biological process that catalyzes carbonate mineral precipitation within geomaterials. This study evaluates the performance and mechanisms of the MICP treatment for flocculating the oil sands fine tailings (FT). Column tests showed that the untreated FT did not decant during the 31 days. However, the MICP technique shortened the dewatering process. To elucidate the mechanisms of the MICP-induced flocculation of the FT, the diffuse double layer (DDL) thickness and microstructure of the specimens were evaluated. Three chemical equilibrium scenarios that gradually considered the MICP-biochemical reactions were explored to analyze the change of the DDL thickness. The results showed that increasing of ionic strength by urea hydrolysis decreased the DDL thickness. The fabric observation indicated that the specimens with the most calcium carbonate precipitation had the densest fabric. In summary, the MICP technique densified the fabric of FT via the ureolysis process and precipitating minerals. }, number={7}, journal={Canadian Journal of Civil Engineering}, publisher={Canadian Science Publishing}, author={Liu, Qianwen and Montoya, Brina M.}, year={2022}, month={Jul}, pages={1310–1316} } @article{nafisi_liu_montoya_2021, title={Effect of stress path on the shear response of bio-cemented sands}, volume={6}, ISSN={["1861-1133"]}, DOI={10.1007/s11440-021-01286-7}, journal={ACTA GEOTECHNICA}, author={Nafisi, Ashkan and Liu, Qianwen and Montoya, Brina M.}, year={2021}, month={Jun} } @article{liu_montoya_2021, title={Microbial-Induced Calcium Carbonate Precipitation to Accelerate Sedimentation of Fine Tailings}, volume={147}, ISSN={["1943-5606"]}, url={https://doi.org/10.1061/(ASCE)GT.1943-5606.0002651}, DOI={10.1061/(ASCE)GT.1943-5606.0002651}, number={10}, journal={JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING}, author={Liu, Qianwen and Montoya, Brina M.}, year={2021}, month={Oct} } @article{wu_liu_deng_yu_feng_yan_2019, title={Expansive soil modified by waste steel slag and its application in subbase layer of highways}, volume={59}, ISSN={["0038-0806"]}, DOI={10.1016/j.sandf.2019.03.009}, abstractNote={Steel slag is a waste by-product of the steel industry. The recycling usage of steel slag is limited due to the mutative chemical compositions it contains and its low cementation. In this investigation, the composition adjustment and activation of steel slag were studied to produce an optimal slag-based composite with improved cementation efficiency. The controlling moduli of cement clinker were introduced to standardise the composite. Subsequently, the composite was used to modify Hefei expansive soil (a kind of engineering waste for swelling properties) in embankment construction. The basic physical properties including free swelling ratio, California bearing ratio, unconfined compressive strength, microstructure, and mineral evolution were evaluated to understand the engineering performance and mechanism of modified expansive soils. The results show that the cementation of the slag was significantly improved after the composition adjustment and activation. Furthermore, the treated soil can satisfy the requirement of the Chinese standard for first-class road/highway when the composite incorporation ratio is more than 5%. The microstructural and mineralogical analysis shows that the component adjustment and activation enrich the cementation of the slag, resulting in the suppression of the swelling potential and improved strength. The above findings improve the reuse efficiency of steel slag, especially in expansive soil modifications.}, number={4}, journal={SOILS AND FOUNDATIONS}, author={Wu, Jun and Liu, Qianwen and Deng, Yongfeng and Yu, Xinbao and Feng, Qi and Yan, Chao}, year={2019}, month={Aug}, pages={955–965} } @misc{zamani_liu_montoya_2018, title={Effect of Microbial Induced Carbonate Precipitation on the Stability of Mine Tailings}, url={http://dx.doi.org/10.1061/9780784481615.024}, DOI={10.1061/9780784481615.024}, abstractNote={Dams and impoundments are the most conventional method for depositing mine tailings material. Regular operation of the tailings dams often increase the height of the dams, which may make them susceptible to failure. Many existing mine tailings dams are prone to slope failure and require remediation. In this study, microbial induced calcium carbonate precipitation (MICP) is presented as a new method to improve the stability of mine tailings dams against slope failure. MICP also has the potential to improve other deficiencies of the mine tailings material such as surface erosion, static liquefaction, and dynamic liquefaction. In the present study, Slope/W program is used to perform slope stability analysis and observe the effect of MICP on the static slope stability of mine tailings material. The results show an increase in the slope stability after biocementation. The level of improvement in the factor of safety against slope failure depends on the level of treatment.}, number={298}, journal={IFCEE 2018}, publisher={American Society of Civil Engineers}, author={Zamani, Atefeh and Liu, Qianwen and Montoya, Brina M.}, year={2018}, month={Jun}, pages={291–300} } @article{deng_liu_cui_wang_liu_2019, title={Revisiting Relationships among Specific Surface Area, Soil Consistency Limits, and Group Index of Clays}, volume={47}, ISSN={["1945-7553"]}, DOI={10.1520/JTE20170257}, abstractNote={Abstract Investigations correlating specific surface area (SSA) with other soil parameters like consistency limits are helpful in understanding the internal meaning of soil properties. In this study, a large database (267 groups of test results) from the literature is established, and the performed statistical analyses show that the traditional relationship with limited data may be invalid when large data are involved. Hereafter, there is a relatively good relationship between the soil consistency limits and SSA when the threshold SSA value (about 80 m2/g) is identified, which suggests that the soils totally behave as pellets and platelets in the geometry, respectively, before and after this value. Despite the fact that this threshold SSA should complicatedly depend on the crystalline formation, clay mineral, and clay fraction in the particle size distribution, this threshold is relatively reliable in view of these large data statistics. Additionally, the group index by ASTM and the methylene blue value by Laboratoire Centrale des Ponts et Chaussées in France can be mutually converted to characterize subgrade soils to account for the established relationship between consistency limits and SSA.}, number={2}, journal={JOURNAL OF TESTING AND EVALUATION}, author={Deng, Yongfeng and Liu, Qianwen and Cui, Yujun and Wang, Qiong and Liu, Songyu}, year={2019}, month={Mar}, pages={1392–1404} }