Mechanical Performance of Biotreated Sandy Road Bases

Xiao, Yang; Xiao, W.; Ma, Guoliang; He, Xiang; Wu, Huanran; Shi, Jinquan

doi:10.1061/(asce)cf.1943-5509.0001671

Cited by 28 publications

(9 citation statements)

References 48 publications

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“…Failure mode is another important aspect of the mechanical responses, apart from the stress–strain characteristics. Inclined shear bands and vertical tensile cracks are the two often observed failure modes in the uniaxial compression tests on MICP‐treated sands 84,85 . The failure mode might be affected by many uncertainties during the experimental process, for example, the inhomogeneity of the specimen and the contacting properties between the specimen and loading platen.…”

Section: Resultsmentioning

confidence: 99%

“…Inclined shear bands and vertical tensile cracks are the two often observed failure modes in the uniaxial compression tests on MICP-treated sands. 84,85 The failure mode might be affected by many uncertainties during the experimental process, for example, the inhomogeneity of the specimen and the contacting properties between the specimen and loading platen. Numerical simulations have some major advantages over experiments in this aspect, thanks to the well-controlled specimen preparation and boundary conditions.…”

Section: Failure Mode Analysismentioning

confidence: 99%

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3D DEM modeling of biocemented sand with fines as cementing agents

Liang

et al. 2022

Num Anal Meth Geomechanics

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Microbially induced calcium carbonate precipitation (MICP) has attracted much attention as a promising green technique for soil improvement. Despite the significance of precipitation pattern in mind, constitutive relations or numerical models considering the finite-strain mechanical effects of the various precipitation patterns are rarely developed. In this paper, we propose a novel 3D DEM modeling scheme by using coarse particles to represent sand grains and fines as cementing agents, to reproduce the various precipitation patterns in MICPtreated sand. Based on the topological relations with adjacent particles and the contribution to the mechanical improvement, the cementing fines are classified into effective, partially effective, surface coating, and pore filling ones. The microstructural characteristics and their evolution upon external loading are investigated quantitatively after a careful calibration and validation. The microstructural variation in experiments can be well reproduced, pinpointing this variation as a possible cause for the fluctuation in experimental data. Massive coating fines are produced accompanying the microstructural degradation, which is initiated by the breakage of effective bonds. The breakage of partially effective bonds may become dominating later in the medium to strong cemented specimens. One weakly cemented specimen shows diffuse failure with simultaneous bond-breakage and friction. In contrast, the medium to strong cemented specimens show localized failure with the dominating mechanism transiting from bond-breakage to friction producing notable pore filling fines. We propose a relation between unconfined compressive strength and the equivalent effective volume fraction of cementing agents normalized by the pretreatment porosity, which reveals the coupling effects of the initial configuration and the precipitation pattern on the mechanical improvement.

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Section: Resultsmentioning

confidence: 99%

Section: Failure Mode Analysismentioning

confidence: 99%

3D DEM modeling of biocemented sand with fines as cementing agents

Liang

et al. 2022

Num Anal Meth Geomechanics

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“…The particle-scale mechanical characteristics of interparticle biocementation are likely affected by the properties of particulate materials. Quartz and calcareous sands are the two common materials encountered in the MICP treatment (Cui et al 2017;Liu et al 2019;Xiao et al 2022d). Given the great impact of particle shape on the mechanical responses (Xiao et al 2019c, d), spherical quartz beads (SQBs, i.e., glass beads from BKMAM, Changde, Hunan) and spherical calcareous beads (SCBs, i.e., homemade natural coral sands from the South China Sea) are adopted as the particles for cementation.…”

Section: Experimental Details and Testing Proceduresmentioning

confidence: 99%

Fracture of Interparticle MICP Bonds under Compression

Xiao

et al. 2023

Int. J. Geomech.

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Microbiologically induced calcium carbonate precipitation (MICP), as a promising reinforcement technique, has been investigated extensively through element and model tests. However, tests on the particle-scale behaviors of MICP bonds are rarely conducted yet, which constrains the development of constitutive and numerical models of MICP-treated sands. In this paper, a set of devices is designed to form MICP bonds between spherical quartz beads (SQBs) and spherical calcareous beads (SCBs) and investigate the microscopic compression behavior of the interparticle MICP bonds in comparison with portland cement (PC) bonds. The experimental results reveal that the PC bonds are the strongest, whereas the MICP bonds between SQB are the weakest. A higher cementation degree leads to higher strength and smaller dispersion among parallel specimens, while a larger interparticle distance causes smaller strength and greater dispersion. Identified with force-displacement curves and optical photos, the PC-treated SQB specimens are dominated by brittle failure, the MICP-treated SQB specimens can present ductile or brittle failure, and possible grain crushing is observed in the MICP-treated SCB specimens. Scanning electron microscopy (SEM) images suggest better interfacial bonding for the MICP-treated SCB specimens than for the MICP-treated SQB specimens. Gravity-related inhomogeneity is observed in the MICP bonds, whereas a homogeneous dense microstructure is observed in the PC bonds.

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“…In addition, Whiffin (2004) successfully manufactured the first biocemented sand column using bacteria, which opened a new era for manipulating the engineering characteristics of geomaterials using biological methods. Various biotreated methods have been developed to tackle geotechnical problems (Decho 2010;, for example, biocementation to improve soil strength and reduce erosion and seepage Gomez et al 2018a;Nassar et al 2018;Li et al 2019;Montoya et al 2019;Wu et al 2019b;Xiao et al 2022c), biodesaturation to enhance liquefaction resistance (Rebata-Landa and Santamarina 2012; He et al 2013O'Donnell et al 2017a;Nakano 2018;O'Donnell et al 2019;Mousavi and Ghayoomi 2021;Wang et al 2021a), bioclogging or biosealing (Davis et al 2009;Mitchell et al 2010Mitchell et al , 2013Phillips et al 2013a, b;DeJong et al 2016;Phillips et al 2018;Kirkland et al 2020), and the bioremediation of heavy metal and oil pollution in soil and water (Davis et al 2003;Wang and Chen 2006;Keimowitz et al 2007;Beolchini et al 2009;Wang and Zhao 2009;Luo and Gu 2011;Zhao et al 2015;Beolchini et al 2017;Cheng and Shahin 2017;Cornu et al 2017;Li et al 2017b;Qi et al 2018;Shapiro et al 2018;Naguib et al 2019;Asta et al 2020;…”

Section: Introductionmentioning

confidence: 99%

Review of Strength Improvements of Biocemented Soils

Xiao

Zaman

et al. 2022

Int. J. Geomech.

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Microbially induced calcium carbonate precipitation (MICP) has attracted great attention recently for its ability to improve the mechanical properties of soils. Calcium carbonate (CaCO 3 ) precipitates that formed at the contact points and on the surface of particles or in the pore space of soil matrixes could increase the bonding strength, friction, and interlocking resistances due to the enhancement of the interparticle bonds, particle roughness, and packing density, and therefore, greatly improve the macroscopic performances of biocemented soils that were subjected to external loading. Strength is one of the key factors when determining the application of biotreatments in geotechnical engineering during the construction and operation periods. This study presented a systematic, objective, and extensive review of the strength of biocemented soils that was based on previous research. The improvement characteristics were comprehensively investigated under compression, tension, and static and cyclic shear conditions, for unconfined compressive (UCS), splitting tensile (STS), yielding, shear, and cyclic resistance strengths. Particle scale regimes were elaborated to interpret the improvement mechanism in the biotreatment and failure modes in biocemented specimens under external loading. Furthermore, the challenges of biocementation were discussed, and future investigations were envisioned.

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Mechanical Performance of Biotreated Sandy Road Bases

Cited by 28 publications

References 48 publications

3D DEM modeling of biocemented sand with fines as cementing agents

3D DEM modeling of biocemented sand with fines as cementing agents

Fracture of Interparticle MICP Bonds under Compression

Review of Strength Improvements of Biocemented Soils

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