scholarly journals Affectivity of biological cement's application to sandy soil for geotechnical engineering

2018 ◽  
Vol 169 ◽  
pp. 01011
Author(s):  
Hung Wen Yi ◽  
Emma Yuliani ◽  
Maytri Handayani ◽  
Hsu Chia Sseng ◽  
Chen Ssu Ching
Keyword(s):  
Sandy Soil ◽  
Environmental Scanning Electron Microscopy ◽  
Friction Angle ◽  
Soil Stability ◽  
Precipitation Process ◽  
Ratio Test ◽  
Calcite Precipitation ◽  
Soil Particles ◽  
Filling Materials ◽  
Urease Enzyme

In this research, the authors analyze the addition of bacterial producer of biological cement on sandy soil to increase its stability. Pseudomonas sp was injected into the soil to produce urease enzyme, which converts urea that reacted with water become ammonium and carbonate, causing calcite precipitation. Soil stability can be improved by the production of pore-filling materials and particle-binding materials through the calcite precipitation process. The aim of these applications is to improve the mechanical properties of soil that it will be more suitable for construction or environmental purposes. After bacterial inoculation, the experiment with variation of bacterial content concluded the best way to increase soil stability is inject 15% bacteria relative to total weight of soil. Highest permeability reduction is 73,73% and highest shear strength increation for cohesion is 6,84 with friction angle 44,46°. California Bearing Ratio test with 10 of hits generated that the treatment soil can proved a significant penetration stress changed. From Environmental Scanning Electron Microscopy test results of the inoculation sand test images and surface scan, the formed exopolysaccharide attached to the wall of the sand soil particles which expected will fill, patch, and close the pores between the sandy soil particles.

scholarly journals Improving Shear Strength Parameters of Sandy Soil using Enzyme-Mediated Calcite Precipitation Technique

2018 ◽  
Vol 20 (2) ◽  
pp. 91 ◽  
Author(s):  
Heriansyah Putra ◽  
Hideaki Yasuhara ◽  
Naoki Kinoshita ◽  
Erizal . ◽  
Tri Sudibyo
Keyword(s):  
Shear Strength ◽  
Sandy Soil ◽  
Friction Angle ◽  
Soil Improvement ◽  
Soil Mass ◽  
Shear Strength Parameters ◽  
Calcite Precipitation ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Potential Applications

Several methods have been established for their various potential applications as soil improvement technique, and recently the application of grouting technique using biological process have been proposed. This study discussed the applicability of enzyme-mediated calcite precipitation (EMCP) in improving the shear strength parameters of sandy soil.  In this study, soil specimens were prepared and treated with the grouting solutions composed of urea, calcium chloride, magnesium sulfate and enzyme of urease. Evolutions in the cohesion and internal friction angle of the improved soil were examined through the direct shear tests. The presence of the precipitated materials, comprising 4.1 percent of the soil mass of the treated sand, generated a cohesion of 53 kPa. However, contrary to the improvement of cohesion, the friction angle is relatively constant. It indicated that the application of the EMCP technique has no significant impact on the friction angle

scholarly journals Review of Enzyme-Induced Calcite Precipitation as a Ground-Improvement Technique

2020 ◽  
Vol 5 (8) ◽  
pp. 66 ◽  
Author(s):  
Heriansyah Putra ◽  
Hideaki Yasuhara ◽  
Erizal ◽  
Sutoyo ◽  
Muhammad Fauzan
Keyword(s):  
Sandy Soil ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Engineering Properties ◽  
Future Research ◽  
Mixed Solution ◽  
Calcite Precipitation ◽  
Urease Enzyme ◽  
Challenges And Opportunities ◽  
Strength And Stiffness

Calcite-induced precipitation methods (CIPMs) have recently become potential techniques in geotechnical engineering for improving the shear strength of sandy soil. One of the most promising methods among them is enzyme-induced calcite precipitation (EICP). In this technique, a mixed solution composed of reagents and the urease enzyme, which produces calcite, is utilized as the grouting material. The precipitated calcite in granular soil provides ties among the grains of soil and limits their mobility, thus promoting an improvement in strength and stiffness and also a reduction in the hydraulic conductivity of sandy soil. This paper discusses the potential increase in the strength and stiffness of the soil, the additional materials for grouting, the effect of these materials on the treatment process, and the engineering properties of the soil. The possible sources of the urease enzyme and the applicability of the EICP method to other soil types are also discussed in this paper. The environmental and economic impacts of the application of EICP are also presented. The envisioned plans for application, potential advantages, and limitations of EICP for soil stabilization are discussed. Finally, the primary challenges and opportunities for development in future research are briefly addressed.

Enhancing the Strength of Sandy Soil Through Enzyme-Induced Calcite Precipitation

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Abubakar Sadiq Muhammed ◽  
Khairul Anuar Kassim ◽  
Muttaqa U. Zango ◽  
Kamarudin Ahmad ◽  
Jodin Makinda
Keyword(s):  
Sandy Soil ◽  
Calcite Precipitation

scholarly journals Geotechnical engineering behaviors of gellan gum biopolymer treated sand

2016 ◽  
Vol 53 (10) ◽  
pp. 1658-1670 ◽  
Author(s):  
Ilhan Chang ◽  
Jooyoung Im ◽  
Gye-Chun Cho
Keyword(s):  
Geotechnical Engineering ◽  
Friction Angle ◽  
Soil Improvement ◽  
Gellan Gum ◽  
Strengthening Effect ◽  
Calcite Precipitation ◽  
Unconfined Compression Test ◽  
Sand Particles ◽  
Engineering Practices ◽  
Moisture Conditions

Biological approaches have recently been explored as environmentally friendly alternatives to engineered soil methods in geotechnical engineering practices. The use of microbial induced calcite precipitation, reactive enzymes, and microbial polymers, such as biopolymers, in soil improvement has been studied by researchers around the world. In the present study, gellan gum, a microbial polysaccharide generally used in the food industry due to its hydrogel rheology, was used to strengthen sand. The effects of gellan gum on the geotechnical behaviors of cohesionless sand were evaluated through a series of experimental programs including an unconfined compression test, direct shear test, falling head permeability test, and scanning electron microscopy. The geotechnical properties (friction angle, cohesion, and unconfined compressive strength) of gellan gum–treated sands were determined based on varying moisture conditions: initial, dried, and re-submerged. Gellan gum has a distinct strengthening effect on cohesionless sands through artificial cohesion that varies with the moisture conditions. The strengthening effect of gellan gum on sand appears to be a result of the combination of enhanced bonding between unreactive sand particles and the agglomeration of sand particles through hydrogel condensation, in which the agglomerated sand particles behave as enlarged aggregates in soil.

scholarly journals Undrained Behavior of Microbially Induced Calcite Precipitated Sand with Polyvinyl Alcohol Fiber

2019 ◽  
Vol 9 (6) ◽  
pp. 1214 ◽  
Author(s):  
Sun-Gyu Choi ◽  
Tung Hoang ◽  
Sung-Sik Park
Keyword(s):  
Hydraulic Conductivity ◽  
Polyvinyl Alcohol ◽  
Friction Angle ◽  
Triaxial Tests ◽  
Calcite Precipitation ◽  
Environment Friendly ◽  
Ottawa Sand ◽  
Polyvinyl Alcohol Fiber ◽  
Constant Head ◽  
Undrained Behavior

Microbially induced calcite precipitation can cement sand and is an environment-friendly alternative to ordinary Portland cement. In this study, clean Ottawa sand was microbially treated to induce calcite contents (CCs) of 0%, 2%, and 4%. Polyvinyl alcohol fiber was also mixed with the sand at four different contents (0%, 0.2%, 0.4%, and 0.6%) with a constant CC of 4%. A series of undrained triaxial tests was conducted on the treated sands to evaluate the effects of the calcite treatment and fiber inclusion. Their hydraulic conductivity was also determined using a constant head test. As the CC increased from 0% to 4%, the friction angle and cohesion increased from 35.3° to 39.6° and from 0 to 93 kPa, respectively. For specimens with a CC of 4%, as the fiber content increased from 0% to 0.6%, the friction angle and cohesion increased from 39.6° to 42.8° and from 93 to 139 kPa, respectively. The hydraulic conductivity of clean Ottawa sand decreased by a factor of more than 100 as the CC increased from 0% to 4%. The fiber inclusion had less effect on the hydraulic conductivity of the specimen with 4% CC.

Effect of Urease Dosages in Biocementation Process for Improving Strength of Sandy Soil

2014 ◽  
Vol 931-932 ◽  
pp. 698-702 ◽  
Author(s):  
Janjit Iamchaturapatr ◽  
Keeratikan Piriyakul
Keyword(s):  
Calcium Carbonate ◽  
Shear Modulus ◽  
Sandy Soil ◽  
Strength Development ◽  
Biochemical Process ◽  
Solution Ph ◽  
Crystal Forms ◽  
Soil Particles ◽  
Earth Structures ◽  
G Value

Soil biocementation is the new technique using biochemical process to initiate the crystal forms of calcium carbonate (CaCO3) to bind the soil particles resulting in soil mechanical improvement. This research examines the effect of urease (UR) dosages on the strength development of sandy soil in biocemented sand reactor (BSR). Our results found that urease dosages between 5-30% (v/v) affected the strength development in sandy soil in term of shear modulus (G). Addition of UR resulted on an increase of solution pH. Highest solution pH during the treatment was found at UR 20%, as well as highest G value. Formation of CaCO3 in biocemented sand could be useful for the stabilization of the sand or earth structures.

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