scholarly journals Mechanism of Sand Cementation with an Efficient Method of Microbial-Induced Calcite Precipitation

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5631
Author(s):  
Lu Wang ◽  
Shuhua Liu
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Efficient Method ◽  
Sand Particle ◽  
Carbonate Content ◽  
Calcite Precipitation ◽  
Sand Column ◽  
Cemented Sand ◽  
Initial Ph ◽  
Sand Particles

This paper presents an efficient method of microbial-induced calcite precipitation (MICP) for cementation of sand particles. First, the influence of initial pH value of the culture medium on the growth of bacteria was discussed. Then, the compressive strength and calcium carbonate content of cemented sand columns with different sand particle sizes were measured to indicate the cementation effectiveness. The microstructure of cemented sand columns as well as the mineral composition and distribution of calcium carbonate were characterised by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The results showed that the urease-producing bacteria S. pasteurii can be cultured at the initial pH values of 7–10, while a higher pH (e.g., 11) would hinder its growth and decrease its urease activity. The injection method of MICP with high standing time can cement sand columns effectively. Small average sand particle size of sand columns and high injection cycles can facilitate the gain of compressive strength, while calcium carbonate content of sand column higher than 8% can promote the increase of compressive strength. XRD results indicate that the fine grains generated on the surface of sand particles are calcite. The distribution of calcite on sand particles’ surface is broad and uniform. First, calcite was precipitated on the surface of sand particles, and then a precipitation layer was formed, which would connect sand particles through its high enough thickness and contribute to the development of compressive strength of the whole sand column.

scholarly journals Effect of Particle Size on Mechanical Property of Bio-Treated Sand Foundation

2020 ◽  
Vol 10 (22) ◽  
pp. 8294
Author(s):  
Defeng Yang ◽  
Guobin Xu ◽  
Yu Duan
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Sand Particle ◽  
Bacterial Suspension ◽  
Particle Sizes ◽  
Sand Column ◽  
Engineering Characteristics ◽  
Geological Conditions ◽  
Long Time ◽  
Effect Of Particle Size

In the field of geotechnical engineering, microbially induced calcium precipitation technology is feasible and sustainable alternative to improve the engineering characteristics of sand foundation under different geological conditions for a long time. However, it is unclear how the effects of different sand particle sizes on the engineering characteristics of bio-treated sand column. The method of intermittent injection in batches was used to develop a series of bio-treated sand columns. The results showed that the mechanical properties of the bio-treated column improved by increasing the particle size. Low concentration of bacterial suspension and cementation reagent leads to the increase of calcium carbonate and unconfined compressive strength. Additionally, the total injection times increased, thus risking time cost. Furthermore, the increase of sand particle size was beneficial to the uniformity of the spatial distribution of calcium carbonate in the bio-treated column. The coefficient of variation was reduced by up to 52.0%. Scanning electron microscopy results confirmed that the size and uniformity of calcite crystals on the surface of sand particles were related to the concentration of cementation solution.

Solidification of CaCO3 containing SrCO3 by hydrothermal hot-pressing

1993 ◽  
Vol 8 (8) ◽  
pp. 1972-1976 ◽  
Author(s):  
Nakamichi Yamasaki ◽  
Tang Weiping ◽  
Kazumichi Yanagisawa
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Hot Pressing ◽  
Strontium Carbonate ◽  
Reaction Process ◽  
Carbonate Content ◽  
Mechanical Compression ◽  
Hydrothermal Conditions ◽  
Bonding Material

Powders of calcium carbonate with strontium carbonate were solidified by mechanical compression under hydrothermal conditions. The effects of hydrothermal conditions such as temperature, pressure, and ratio of Ca/Sr on the reaction process and microstructure of the solidified bodies were examined. Solidification of every powder easily proceeded with shrinkage above 200 °C to 300 °C. The compacts of strontium carbonate were more easily solidified, and compressive strength was 190 MPa and its density was 93.5%. The solidification with shrinkage of compacts consisting of mixed powders of calcium and strontium carbonates was accelerated with an increase in strontium carbonate content. It was revealed that the small amount of strontium carbonate powder acts as a bonding material among large calcium carbonate particles.

Effects of Shell and Calcium Carbonate on Properties of Portland Cement

2012 ◽  
Vol 450-451 ◽  
pp. 495-498 ◽  
Author(s):  
Gui Yun Wang ◽  
Ling Chao Lu ◽  
Shou De Wang
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Calcium Carbonate ◽  
Portland Cement ◽  
Resistance Coefficient ◽  
Carbonate Content ◽  
Hardened Cement ◽  
Hydration Reaction ◽  
Calcium Carbonate Content ◽  
Acceleration Period

Different amounts of shell and calcium carbonate were added into the Portland cement, their influences on the compressive strength, sulfate corrosion resistance, hydration heat and porosity of the hardened cement paste were studied. Results show that with the increasing of shell content, the compressive strength decreases, however, modest reduction; as the increase of calcium carbonate content, the strength first increases and then decreases, the compressive strength reaches the highest value when the content is 15%. After addition of shell and calcium carbonate, the initial hydration reaction rate accelerates, meanwhile the induction period and acceleration period are brought forward. With the raising of shell and calcium carbonate content, the corrosion resistance coefficient increases gradually, and the sulfate corrosion resistance increases as well. The proportion of the harmless hole which diameter is smaller than 50nm increases after adding the shell and calcium carbonate, it’s beneficial to improve the performance of concrete.

scholarly journals Effect of Nutrient Solution Composition on Bio-Cemented Sand

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1572
Author(s):  
Shihua Liang ◽  
Xueli Xiao ◽  
Zhanlin Li ◽  
Deluan Feng
Keyword(s):  
Calcium Carbonate ◽  
Sodium Bicarbonate ◽  
Calcium Chloride ◽  
Ammonium Chloride ◽  
Nutrient Solution ◽  
Nutrient Broth ◽  
Carbonate Precipitation ◽  
Solution Composition ◽  
Cemented Sand ◽  
Sand Particles

Microbial-induced carbonate precipitation is an environmentally friendly foundation treatment technology that effectively improves soil engineering performance. The various nutrient components of liquid curing compounds significantly influence the curing effect. On the basis of penetration, dry density, water absorption, and unconfined compressive strength tests, this study showed the effect of nutrient solution composition, including urea, calcium chloride, sodium bicarbonate, ammonium chloride, and nutrient broth, on the physicomechanical properties of bio-cemented sand. The morphological differences of calcium carbonate precipitates under nutrient solution composition were compared through scanning electron microscopy (SEM). Results showed that the curing effect of compound nutrient solution was improved compared with the basic nutrient solution (urea and calcium chloride). Among the individual components added, ammonium chloride had the most remarkable effect, followed by sodium bicarbonate and nutrient broth. Among the paired components added, sodium bicarbonate + ammonium chloride had the most significant effect, followed by sodium bicarbonate + nutrient broth and ammonium chloride + nutrient broth. The strength of bio-cemented sand cured with compound nutrient solution containing five components could reach 3.43 MPa, which was 1.92 times higher than the strength of the basic nutrient solution. As shown by the SEM image, the calcium carbonate precipitation in the solidified sand was distributed in the clearance of sand particles, effectively bonding the sand particles. The calcium carbonate obtained by the composition of the compound nutrient solution precipitated the sand particles, and some of the sand particles were wrapped. Moreover, the amount of precipitation was evidently greater than that of the basic nutrient solution. Compared with the basic nutrient solution, the compound nutrient solution effectively reduced the apparent porosity and average pore size of the sand. Thus, the curing effect of the compound nutrient solution was better than that of the basic nutrient solution.

Experimental Research on Unconfined Compressive Strength of Artificially Cemented Sand

2013 ◽  
Vol 689 ◽  
pp. 324-328
Author(s):  
Xin Shan Zhuang ◽  
Can Zhao ◽  
Xu Min Wang
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Quantitative Relation ◽  
Curing Time ◽  
Test Results ◽  
Cemented Sand ◽  
Cement Ratio ◽  
Content Ratio

Unconfined compressive strength tests and calcium carbonate (CaCO3) quantitative chemical tests are conducted on artificially cemented sand which have different cement ratio (Cv) and curing time (t). Through the analysis of experimental results, the unconfined compressive strength (qu) of cemented sand are affected by curing time (t), cement ratio (Cv) and void ratio (η). Test results show that the longer the curing time (t), the lower the void/cement ratio (η/Cv) and the higher calcium carbonate/calcium hydroxide content ratio (CaCO3/Ca(OH)2 ratio or mC/mH), the higher the unconfined compressive strength (qu) of cemented sand. It is established the compressive strength equation based on the variables of cement ratio (Cv), void ratio (η) and curing time (t). By mC/mH-qu curve analysis, it is obtained the quantitative relation of chemical composition and mechanical strength.

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

scholarly journals Statistical Law and Predictive Analysis of Compressive Strength of Cemented Sand and Gravel

2020 ◽  
Vol 27 (1) ◽  
pp. 291-298
Author(s):  
Shoukai Chen ◽  
Yongqiwen Fu ◽  
Lei Guo ◽  
Shifeng Yang ◽  
Yajing Bie
Keyword(s):  
Compressive Strength ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Predictive Analysis ◽  
Distribution Law ◽  
Data Set ◽  
Cemented Sand ◽  
Mix Proportion ◽  
Kolmogorov Smirnov ◽  
Sand And Gravel

AbstractA data set of cemented sand and gravel (CSG) mix proportion and 28-day compressive strength was established, with outliers determined and removed based on the Boxplot. Then, the distribution law of compressive strength of CSG was analyzed using the skewness kurtosis and single-sample Kolmogorov-Smirnov tests. And with the help of Python software, a model based on Back Propagation neural network was built to predict the compressive strength of CSG according to its mix proportion. The results showed that the compressive strength follows the normal distribution law, the expected value and variance were 5.471 MPa and 3.962 MPa respectively, and the average relative error was 7.16%, indicating the predictability of compressive strength of CSG and its correlation with the mix proportion.

scholarly journals Opto‐electrochemical Dissolution Reveals Coccolith Calcium Carbonate Content

2021 ◽  
Author(s):  
Minjun Yang ◽  
Christopher Batchelor-McAuley ◽  
Samuel Barton ◽  
Rosalind E.M. Rickaby ◽  
Heather A. Bouman ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Carbonate Content ◽  
Electrochemical Dissolution ◽  
Calcium Carbonate Content

scholarly journals A Novel Resorbable Composite Material Containing Poly(ester-co-urethane) and Precipitated Calcium Carbonate Spherulites for Bone Augmentation—Development and Preclinical Pilot Trials

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 102
Author(s):  
Claudia Rode ◽  
Ralf Wyrwa ◽  
Juergen Weisser ◽  
Matthias Schnabelrauch ◽  
Marijan Vučak ◽  
...  
Keyword(s):  
Composite Material ◽  
Calcium Carbonate ◽  
Bone Substitute ◽  
Pilot Trial ◽  
Carbonate Content ◽  
Precipitated Calcium Carbonate ◽  
Degradation Behaviour ◽  
Biodegradable Composite ◽  
Loss Of Mass

Polyurethanes have the potential to impart cell-relevant properties like excellent biocompatibility, high and interconnecting porosity and controlled degradability into biomaterials in a relatively simple way. In this context, a biodegradable composite material made of an isocyanate-terminated co-oligoester prepolymer and precipitated calcium carbonated spherulites (up to 60% w/w) was synthesized and investigated with regard to an application as bone substitute in dental and orthodontic application. After foaming the composite material, a predominantly interconnecting porous structure is obtained, which can be easily machined. The compressive strength of the foamed composites increases with raising calcium carbonate content and decreasing calcium carbonate particle size. When stored in an aqueous medium, there is a decrease in pressure stability of the composite, but this decrease is smaller the higher the proportion of the calcium carbonate component is. In vitro cytocompatibility studies of the foamed composites on MC3T3-E1 pre-osteoblasts revealed an excellent cytocompatibility. The in vitro degradation behaviour of foamed composite is characterised by a continuous loss of mass, which is slower with higher calcium carbonate contents. In a first pre-clinical pilot trial the foamed composite bone substitute material (fcm) was successfully evaluated in a model of vertical augmentation in an established animal model on the calvaria and on the lateral mandible of pigs.

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