Abstract
The microbial-induced carbonate precipitation (MICP) method has gained intense attention in recent years as a safe and sustainable alternative for soil improvement and for use in construction materials. In this study, the effects of the addition of plant-based natural jute fibers to MICP-treated sand and the corresponding microstructures were measured to investigate their subsequent impacts on the MICP-treated biocemented sand. The fibers used were at 0%, 0.5%, 1.5%, 3%, 5%, 10%, and 20% by weight of the sand, while the fiber lengths were 5, 15, and 25 mm. The microbial interactions with the fibers, the CaCO3 precipitation trend, and the biocemented specimen (microstructure) were also evaluated based on the unconfined compressive strength (UCS) values, scanning electron microscopy (SEM), and fluorescence microscopy. The results of this study showed that the added jute fibers improved the engineering properties (ductility, toughness, and brittleness behavior) of the biocemented sand using MICP method. Furthermore, the fiber content more significantly affected the engineering properties of the MICP-treated sand than the fiber length. In this study, the optimal fiber content was 3%, whereas the optimal fiber length was s 15 mm. The SEM results indicated that the fiber facilitated the MICP process by bridging the pores in the calcareous sand, reduced the brittleness of the treated samples, and increased the mechanical properties of the biocemented sand. The results of this study could significantly contribute to further improvement of fiber-reinforced biocemented sand in geotechnical engineering field applications.
Highlights
Significant interest in bio-mediated soil improvement has been highlighted as an innovative and effective approach for soil and ground improvement
The results showed that the fracture jute fibers in the microbial-induced carbonate precipitation (MICP)-treated sample significantly improved the unconfined compressive strength, morphologies of the biocemented samples were closely interlinked with the different fiber contents and because of the lower biocementation level, the fractures generally started from the lower end (Figure 16a) and lengths (Figure 16b), due to the interaction and friction within the sand–fiber matrix
The results showed that the fracture morphologies soil matrix, which restricted the development of the failure pattern and effectively improved the of the biocemented samples were closely interlinked with the different fiber contents (Figure 16a) and strength of the soil, while enhancing the brittleness delayed the overall damages of the MICP-treated lengths (Figure 16b), due to the interaction and friction within the sand–fiber matrix
Summary
Significant interest in bio-mediated soil improvement has been highlighted as an innovative and effective approach for soil and ground improvement. Among the various bio-mediated soil development approaches, microbial-induced carbonate precipitation (MICP) has been recognized as a promising approach for soil improvement in recent years. Most of the previous studies [1,2,3,4] have focused on the impacts of various environmental factors on microorganism immobilization and strength improvement using several types of soil materials, including the capability of microorganisms to form CaCO3 within sand particles and pores; the relationship between the precipitated CaCO3 content and the strength of MICP-treated sand; Materials 2020, 13, 4198; doi:10.3390/ma13184198 www.mdpi.com/journal/materials. Materials 2020, 13, 4198 the study of the engineering properties of MICP-treated sand, such as the volume, permeability, strength, and compressibility, which was assessed using introductory numerical simulations [5]. Many recent experiments have demonstrated the mechanism of CaCO3 deposition and improvement of soil strength after curing samples using the MICP method. Earlier research demonstrated the non-uniformity of precipitation of CaCO3 and brittle failure behavior of MICP-treated soil [6]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
