Barite Powder Research Articles

Experimental study on static and dynamic properties of similar materials for engineering rock mass

To determine the static and dynamic properties of similar materials for engineering rock mass, static and dynamic triaxial tests were conducted on similar engineering rock mass materials. The materials comprised barite powder, quartz sand, gypsum powder, water, and laundry detergent, based on an optimal design. The relationship between deviator stress and an axial strain was investigated under various loading and confining pressure. The test results reveal that the deformation characteristics of similar materials gradually develop from brittleness to ductility with an increase in applied confining pressure, and the static and dynamic elastic moduli show an increasing trend. The hysteresis loop area of similar materials becomes larger with an increase in dynamic stress, suggesting a greater damping ratio of similar materials. The results of this study provide a basic reference for the characteristics model test, and the findings can guide the numerical simulation of the stability analysis of super large-span flat cavern in future studies.

Influence of barite particulate filler on the mechanical behaviour of carbon fiber reinforced LY556 epoxy matrix composites

This work is intended to explore the influence of barite particulate filler on the mechanical behaviour of carbon fiber (Cf) reinforced polymer matrix (CFRP) composites. The carbon fiber utilized for the study was T300 grade and the polymer matrix utilized was LY556 epoxy resin (Epr). The CFRP composites prepared with 55 weight (wt.) % T300 carbon fiber and 45 wt.% LY556 epoxy resin without barite particulate filler was utilized for control experimentation. The CFRP composites with barite filler were prepared by varying the proportion of barite particles from 2.5 wt.% to 15 wt.% in steps of 2.5 wt.%. The composites were prepared using the hand lay-up process and the barite particles were mixed with the epoxy resin by means of ultrasonic agitation. The prepared composites were subjected to tension, compression, hardness, flexural and impact testing. The CFRP composites with 10 wt.% barite particles yielded the best tensile strength, hardness and impact strength. The tensile strength, hardness and impact strength attained an increase of 13.18%, 5.6% and 18.68% respectively, compared to the CFRP composite without barite filler. The compressive strength of the CFRP composite with 15 wt.% barite filler was observed to be more than twice the compressive strength of the CFRP composite without barite filler. However, the flexure strength reduced steadily with the addition of barite particulates. The fractured surface morphologies of the prepared composites were characterised using the Scanning Electron Microscope (SEM). The chemical composition and morphology of barite powder was analysed using Energy Dispersive X-Ray Spectroscopy (EDX) and SEM, respectively.

Mixing Ratios and Cementing Mechanism of Similar Silty Mudstone Materials for Model Tests

The similarity model test is one of the important means to study the engineering properties of soft rock. This study aims to develop similar materials for silty mudstone, which has characteristics of low strength and water expansion, based on traditional materials including gypsum, barite powder, clay minerals, and distilled water. The orthogonal design method was used to determine the mixing ratios of the similar materials. The density, uniaxial compressive strength, tensile strength, elastic modulus, and Poisson’s ratio were selected as control indicators of the similar materials. The results show that the water content is the dominant factor for the density, tensile strength, elastic modulus, and Poisson’s ratio of the similar materials of silty mudstone, while the gypsum content is the dominant factor for the uniaxial compressive strength. The physical and mechanical properties of the similar material samples with water content of 19%, barite powder ratio of 32%, and gypsum mass of 250 g show good similarity to those of the raw silty mudstone. The water absorption and expansibility of similar materials with clay mineral ratio of 12% are consistent with those of the raw silty mudstone. The scanning electron microscopy (SEM) observation indicates that the similar material with optimal mixing ratios exhibits a similar microstructure to that of silty mudstone.

SIMILAR MATERIALS FOR QUASI-STATIC SCALED TESTS OF FAULT-CROSSING TUNNELS

The design of similar materials is one of the key links to ensure the matching of the physic-mechanical properties between the prototype and the test specimens. Based on the prototype of the Xianglu mountain tunnel of the water diversion project in the central Yunnan province, China, the scaling relationship of the physical quantities in the quasi-static scaled test of a fault-crossing tunnel is derived in this study according to the similarity theory and dimensional analyses. The similar materials of concrete and rock mass used in the test are developed with barite powder and sand as the aggregates and with gypsum and lime as the cementing material. The effects of each component on the physic-mechanical properties of the similar materials are investigated through orthogonal tests. The test results indicate that the strength, elasticity modulus and density of the similar materials can be significantly changed by the overall content of the high-strength gypsum and water-gypsum ratio. Small variation of the strength of the similar material is found when the sand-gypsum ratio is between 0.8 and 1.2, but the strength significantly decreases when the sand-gypsum ratio is between 3 and 12. The elastoplastic performance and the brittle failure mode of Grade C30 concrete can be well simulated by the similar material made of high strength gypsum, low strength gypsum, barite powder and sand. The tensile splitting and the diagonal shear failure modes of rock mass of Grade IV and V can be well simulated by the proposed similar material made of high strength gypsum, lime and sand. The development process and ratios of similar materials can provide important reference for model test and numerical simulation.

Mechanical properties and reasonable proportioning of similar materials in physical model test of tunnel lining cracking

Similar materials of surrounding rock and lining suitable for crack of tunnel lining are developed through numerous matching tests according to the numerous theory of geomechanical model test to study the mechanism of crack damage of long-span tunnel lining and the variation rules, such as load and deformation, of physical fields. Similar material of surrounding rock is composed of quartz sand as coarse aggregate, barite powder as fine aggregate, and oil, vaseline, and paraffin as binder. Similar material of lining is based on gypsum and quartz sand, diatomite, fly ash, barite powder, and cement as additives. Physical and mechanical parameters such as uniaxial compressive strength, elastic modulus, and cohesion of materials are controlled through uniaxial compressive, direct shear, and splitting tests. The influence laws of mechanical parameters under various ratios are systematically studied. Test results show that the mechanical parameters of similar material of surrounding rock made of quartz sand, barite powder, and vaseline are stable. The range of variation is moderate, and the fabrication is convenient. The adjustment range of physical and mechanical parameters of similar materials in surrounding rocks is 30.1–52.2 MPa of elastic modulus, 0.23–0.33 MPa of uniaxial compressive strength and 2147–2396 kg/m3 of gravity. In the range of 1.2–2 water paste ratio, gypsum mixture is linearly weakened, and various admixtures strongly influence the mechanical properties of similar materials. Quartz sand as admixture can better replace aggregate in concrete. When the sand content is less than 20%, adding quartz sand into gypsum material can significantly improve the elastic modulus of the material, and the compressive strength changes minimally. When the sand content is more than 20%, the elastic modulus is basically unchanged and the compressive strength gradually decreases. When this similar material is applied to the model test of Fucunchuan tunnel lining crack in the Huangyan Road Capacity Expansion Project, the mechanical and physical properties meet the test requirements. The material can effectively simulate the development and evolution of cracks, provide material basis for obtaining good test results, and serve as a reference for the selection of similar materials for a similar model test.

Study and Application of Similar Material Ratio in Collapsible Loess

The similar material of collapsible loess is the basis and premise of the experimental study on the surface movement and deformation law of coal seam mining in collapsible loess‐covered areas. The orthogonal experiment is used to make up similar material with different proportions using river sand and barite powder as aggregate, clay and gypsum as cementing material, and diatomite as adjusting material. The reasonable proportion of similar material in collapsible loess is studied by using range analysis, similar simulation, and field measurement. The results show that the content of diatomite plays a leading role in the collapsibility coefficient of similar material, and the collapsibility coefficient is positively correlated with the content of diatomite; moisture content is the main control of the cohesion of the material, and cohesion is negatively correlated with the moisture content; the ratio of bone‐to‐glue has the most significant effect on the internal friction angle, and the internal friction angle is positively correlated with the ratio of bone‐to‐glue. The reasonable ratio of the similar material in collapsible loess is 8 : 2 of the ratio of bone‐to‐glue, the ratio of clay‐to‐gypsum is 9 : 1, the barite powder content is 6%, the diatomite content is 23%, and the moisture content is 13%, and the mechanical parameters of the collapsible loess are 5.3%–6.3% different from the target value of similar material through laboratory tests, which can meet the experimental requirements. It is verified by a similar simulation experiment that the maximum surface subsidence value and the surface fracture width in the simulation results are 6.9% and 7.8% different from the field measured results, indicating a high degree of agreement. The results of the study have important references and guiding significance for the preparation of similar material with similar models.

Radiation Shielding Properties Prediction of Barite used as Small Aggregate in Mortar

Construction materials used in the nuclear industry used to be mainly heavy materials, including lead plates, radiation-resistant heavy concrete, etc. However, these materials are either toxic after a long time of use (lead) or difficult to construct (radiation-resistant heavy concrete) and their cost is rather high. Therefore, there is a need for the manufacturing of a new kind of material with good radiation resistance, which is light, easy to use, and costs less. Barium is less toxic and more cost-effective than lead. Due to the importance of barium compounds in radiation shielding, the study of gamma radiation interactions within these compounds becomes essential, so the most important part of such a study is the experimental one, which shows the effect of the barite powder in the radiation resistance of the mortar. The research results show that the higher the thickness and percentage of barite powder, the higher is the radiation resistance.

Numerical Simulation of Shallow Geothermal Field in Operating of a Ground Source Heat Pump System—A Case Study in Nan Cha Village, Ping Gu District, Beijing

The inefficient use of single energy and cold accumulation in the shallow geothermal field seriously affect the efficient operation of the ground source heat pump system (GSHPS). The operation of solar-assisted GSHPS can effectively solve the above problems. In this paper, a shallow geothermal utilization project in Nan cha Village, Ping Gu District of Beijing, is chosen as the study area. A three-dimensional numerical model of groundwater flow and heat transfer considering ambient temperature and backfill materials is established, and the level of model integration and validation are novel features of this paper. The thermal response test data in summer and winter conditions are used to validate the model. The results show that increasing hydraulic gradient has a positive impact on the heat exchange. The mixture of sand and barite powder is recognized as a more efficient and economical backfill material. The changes of thermal influence radius, heat balance, and shallow geothermal field are simulated and analyzed by three schemes. It is demonstrated that the thermal influence radius is 5 m, 3.9 m and 3.9 m for Scheme 1, Scheme 2 and Scheme 3, respectively. The ground temperature is always lower than the initial formation temperature in Scheme 1 and Scheme 2; however, under Scheme 3 it is higher than the initial values. The closer the hole wall is, the larger the difference between the initial formation temperature and the ground temperature, and vice versa. The thermal equilibrium of Scheme 1, Scheme 2 and Scheme 3 is −728 × 106 KJ, −269 × 106 KJ and +514 × 106 KJ. Through comprehensive analysis of the above three factors, Scheme 3 is regarded as the most reasonable scheme for a solar system to assist GSHPS.

Experimental Development Process of a New Cement and Gypsum-Cemented Similar Material considering the Effect of Moisture

A new type of similar material considering water characteristics is developed through orthogonal experiments. The similar material is composed of river sand, barite powder, cement, gypsum, and water. We determine the best test development process. First, the proportion test scheme is designed based on the orthogonal test. Then, the effects of the moisture content, mass ratio of aggregate to binder and other components on the density, uniaxial compressive strength, elastic model, and Poisson’s ratio of similar materials are analyzed by range analysis. Finally, the multiple linear regression equation between the parameters and the composition of similar materials is obtained, and the optimal composition ratio is determined according to the relationship between the test’s influencing factors and the mechanical properties of similar materials. The results show that the selected raw materials and their proportioning method are feasible. The content of barite powder plays a major role in controlling the density and Poisson’s ratio of similar materials. The mass ratio of aggregate to binder is the main factor that affects the uniaxial compressive strength and elastic modulus of similar materials, while the moisture content has the second largest effect on the density, uniaxial compressive strength, elastic modulus, and Poisson’s ratio of similar materials. When the residual moisture content increased from 0 to 4%, the uniaxial compressive strength and elastic modulus of similar materials decrease by 49.5% and 53.3%, respectively, and Poisson’s ratio increases by 54.8%. Determining the residual moisture content that matches the design of similar material model tests is critical to improving the test accuracy and provides a reference to prepare similar materials with different requirements.

Development and Application of Fluid-Solid Coupling Similar Materials in Discharge Test of Old Goaf Water

To study the evolution law of the discharge pathway for the old goaf water in the Datong mining area, a new fluid-solid coupling similar material was developed based on the fluid-solid coupling similarity theory. In the developed similar material, sand and barite powder were used as aggregate, polyurethane and white portland cement as binder, and water and silicone oil as regulator. The effects of different proportions on mechanical properties and water physical properties of materials were obtained through the experiments. The results show that the strength of the developed material is mainly controlled by cement and polyurethane, the hydrophilicity is affected by silicone oil, and the permeability coefficient is mainly affected by cement and polyurethane. For grouting agent, cement can realize the overall control function, and polyurethane can realize the local control in a certain range. As an ideal fluid-solid coupling similar simulation material, the developed material can simulate rock mass with different permeability and different strength. Besides, this material has been successfully applied to an experimental study on the mechanism of old goaf water discharge in an extra-thick coal seam in the Datong mining area, and the development and evolution characteristics of the old goaf water discharge pathway is obtained. This new kind of fluid-solid coupling similar material is developed based on the fluid-solid coupling similarity theory, which is suitable for revealing the evolution law of discharge pathway for the old golf water in the Datong mining area.

Rheological study of heavy cement grouts with physical and chemical characterization of barite powder

This study aims to prepare heavy cement grouts mixtures with different contents of barite powder. Different analytical techniques were used to characterize barite. The Fourier transform infrared and Raman spectroscopy showed that barite has C3ν as a symmetry site. The scanning electron microscopy coupled with X-ray, and X-ray fluorescence showed that barite is the main mineral appearing as platelets. The study of physical properties of mixtures showed that 15% of barite can maintain a normal consistency (5–6 mm). The setting time was inversely proportional to BaO content. The steady-state flow was conducted using a controlled-stress rheometer. The obtained results showed that the mixtures exhibit shear thinning behavior and the presence of barite leads to different rheological behavior as a function of the percentage used. The critical shear rate was proportional to barite content in mixtures prepared by addition and inversely proportional in those prepared by substitution. Concerning yield stress, substitution by 15% leads to a best formulation characterized by low yield stress compared to controller grout.

Numerical Simulation of a Flow Field in a Turbo Air Classifier and Optimization of the Process Parameters

Due to the rapid development of powder technology around the world, powder materials are being widely used in various fields, including metallurgy, the chemical industry, and petroleum. The turbo air classifier, as a powder production equipment, is one of the most important mechanical facilities in the industry today. In order to investigate the production efficiency of ultrafine powder and improve the classification performance in a turbo air classifier, two process parameters were optimized by analyzing the influence of the rotor cage speed and air velocity on the flow field. Numerical simulations using the ANSYS-Fluent Software, as well as material classification experiments, were implemented to verify the optimal process parameters. The simulation results provide many optimal process parameters. Several sets of the optimal process parameters were selected, and the product particle size distribution was used as the inspection index to conduct a material grading experiment. The experimental results demonstrate that the process parameters of the turbo air classifier with better classification efficiency for the products of barite and iron-ore powder were an 1800 rpm rotor cage speed and 8 m/s air inlet velocity. This research study provides theoretical guidance and engineering application value for air classifiers.

Mechanical and Shielding Properties of Concrete Subject to Gamma-ray

In this research, concrete with different percentages of 0, 10, 25, 50, 75 and 100 of barite powder and 10% of graphite powder were investigated for the study of gamma protective properties. The transmitted fluxes of gamma-rays that were emitted from Cs-137 source were detected by a NaI(Tl) detector and analyzed by an MCA analyzer. Then, the samples were tested for compressive strength, tensile strength, ultrasonic pulse wave velocity and the linear attenuation coefficients. By comparing the obtained samples, it was observed that a sample containing 10% barite powder plus 10% graphite powder could be used as a protective material against gamma rays.

Rheological and Mechanical Properties of Heavy Density Concrete Including Barite Powder

Heavy weight concretes (HWCs) or heavy density concretes are commonly used for radiation shielding in nuclear plant to ensure protection against X-rays and Gamma rays. It can also be required in other structures where a large mass is needed. This experimental study was effected to design a HWC, which can be used in bentonite-bored piles concreting in order to remove as much as possible the amount of mud that resides in the pile. In this study, barite is used as fine aggregate mixed with Portland cement to design HWC. Different barite concrete mixes were designed, where barite is used once as an addition while maintaining constant the amount of cement (400 kg/m3) and as a substituent, with different percentage (38, 46, 53 and 57%) to reach different concrete densities. The effect of barite on rheological, heat hydration and mechanical behavior of concrete was investigated. The use of barite as an addition leads to an increase in viscosity and yield stress of concrete; however, when barite is used as a cement substituent, a viscosity decrease is recorded. Barite concrete has shown a lower heat of hydration generation in comparison with a standard mix, which is correlated with compressive strength results.

Similar Materials and Engineering Application of Cemented Sand and Gravel Dam Model

This paper takes the cemented sand and gravel dam (CSGD) in Shoukoubao reservoir as the prototype to introduce in detail the similarity principle of model test and describe the selection steps of materials for CSG model. It has developed similar materials for CSGD model by mixing coarse sand, barite powder, gypsum powder, cement, and iron powder so as to provide reference for CSGD model test in the future. The dam model test has studied the stress distribution and displacement deformation of the dam during construction and normal operation, in order to provide experimental support for the study of failure mechanism of the CSGD and facilitate the design and construction of dams of this kind. The stress level of the body and the foundation of the model dam varied from 1/9 to 1/17 of the designed compressive strength of dam material. The results showed that CSGD is a safe new type of dams.

Experimental Research and Sensitivity Analysis of Mudstone Similar Materials Based on Orthogonal Design

Due to the strong hydration sensitivity of mudstone, drilling of deep mudstone is difficult and pricy, which results in the study on its physical and mechanical properties inseparable from similar material tests. On these bases, triaxial compression and Brazilian tensile tests of the original mudstone drilled from the caprock of the D5 aquifer structure are carried out. Then, orthogonal experiments of mudstone similar materials with river sand and barite powder as aggregate and cement and gypsum as the binder are conducted, which include 3 factors that, respectively, are mass ratio of aggregate to binder, mass ratio of cement to gypsum, and barite powder content, and each factor contains 5 levels, totalling 25 groups of 150 samples. By comparing the results of mudstone and artificial samples made of similar materials, it is obvious that artificial samples and mudstone are significantly similar in terms of density, compressive strength, elastic modulus, and compressive strength when the aggregate‐binder ratio is about 4, 8, 5, and 4, respectively. Further sensitivity analysis showed that the aggregate‐binder ratio played a major role in controlling the properties of artificial samples, while the sensitivity of different parameters to the cement‐gypsum ratio and barite content was different. The results indicate that the selected raw materials and their proportion are feasible, which can meet similar requirements and can be a reference for similar material experimental research of target mudstone.

Prevention of Barite Sag in Oil-Based Drilling Fluids Using a Mixture of Barite and Ilmenite as Weighting Material

Drilling high-pressure high-temperature (HPHT) wells requires a special fluid formulation that is capable of controlling the high pressure and is stable under the high downhole temperature. Barite-weighted fluids are common for such purpose because of the good properties of barite, its low cost, and its availability. However, solids settlement is a major problem encountered with this type of fluids, especially at elevated downhole temperatures. This phenomenon is known as barite sag, and it is encountered in vertical and directional wells under static or dynamic conditions leading to serious well control issues. This study aims to evaluate the use of barite-ilmenite mixture as a weighting agent to prevent solids sag in oil-based muds at elevated temperatures. Sag test was conducted under static conditions (vertical and inclined) at 350 °F and under dynamic conditions at 120 °F to determine the optimum ilmenite concentration. Afterward, a complete evaluation of the drilling fluid was performed by monitoring density, electrical stability, rheological and viscoelastic properties, and filtration performance to study the impact of adding ilmenite on drilling fluid performance. The results of this study showed that adding ilmenite reduces sag tendency, and only 40 wt.% ilmenite (from the total weighting material) was adequate to eliminate barite sag under both static and dynamic conditions with a sag factor of around 0.51. Adding ilmenite enhanced the rheological and viscoelastic properties and the suspension of solid particles in the drilling fluid, which confirmed sag test results. Adding ilmenite slightly increased the density of the drilling fluid, with a slight decrease in the electrical stability within the acceptable range of field applications. Moreover, a minor improvement in the filtration performance of the drilling fluid and filter cake sealing properties was observed with the combined weighting agent. The findings of this study provide a practical solution to the barite sag issue in oil-based fluids using a combination of barite and ilmenite powder as a weighting agent to drill HPHT oil and gas wells safely and efficiently with such type of fluids.

Ultra-low permeability rock-analogue material for gas–solid coupling model tests

In fluid–solid coupling model tests, most existing rock-analogue materials have high permeability, making them unsuitable for gas–solid coupling model tests. Here, a new type of rock-analogue material was developed, which catered to gas–solid coupling model tests that used iron powder, barite powder and quartz sand as aggregates, a special cement as a binder and a cement sealant as a regulator. The physical and mechanical parameters of the material and its influence patterns were determined by laboratory tests. The results showed that the material had a uniaxial compressive strength of 4·16–8·8 MPa and a permeability of 1–460 × 10−3 mD, which is stable at a gas pressure of 1·5 MPa. The density, uniaxial compressive strength, modulus of elasticity and permeability of the material could be precisely adjusted by the moulding pressure, binder content and regulator content. The material can be used to simulate rock with high strength and ultra-low permeability in gas–solid coupling model tests. A model test of coal and gas outburst triggered by roadway excavation was successfully performed using this material to simulate the roof rock and floor rock of a coal seam with low permeability, which demonstrates the feasibility and applicability of the material.

EXPERIMENTAL STUDY ON PROPERTY OF DYNAMIC SIMILAR MATERIAL MADE OF DIFFERENT RAW MATERIALS

With the development of dynamic model test such as centrifuge and shaking table, the requirement for dynamic similar material is more detailed. On the basis of dynamic similitude theory of model test, how to select the ratio of raw materials accurately plays an important role in the model test. This paper selects river sand with different particle gradations, iron powder, barite powder and mica sheet as the raw materials, and jet cement as the cementing agent. It then studies the physical and mechanical property of the similar materials with the elastic wave speed simulation measurement and uniaxial compressive test. The results show the follows. (1)The density, dynamic and static elasticity modulus of the specimens with better particle gradation are bigger and the sand-blinder ratio has a greater influence on the density of similar material as the gap gradation enlarges. (2)The dynamic similar material can be obtained whose density is between 1.5-2.2g·cm-3, dynamic Poisson's ratio is between 0.2-0.4 and dynamic elasticity modulus is between 2.5-5.5Gpa if we choose the river sand as aggregate and cement as cementing agent. (3)Iron powder has better effect on gaining weight than the barite powder. The dynamic and static elasticity modulus of the barite specimen have no obvious changes with the change of barite powder content. Therefore, barite powder is an ideal raw material to make dynamic similar material with high-density and low-strength. (4)With the increase of mica sheet content, the dynamic Poisson's ratio, dynamic and static elasticity modulus of specimen can reduce evidently. As a result, the mica sheet is not suitable for similar material with high density but it can make similar material of weak intercalation or structural plane.

Permeability and Gamma-Ray Shielding Efficiency of Clay Modified by Barite Powder

Environmental protection around radioactive waste disposal is a very important issue for safety purposes. Consequently, permeability and radiation shielding are the two important factors for isolating radioactive disposals. Clay is relatively impermeable soil that is naturally available, cheap and environmentally friendly. In this research, the influence of modifying clay by barite powder was investigated to improve the gamma ray shielding performance while keeping the low permeability of clay soil. This research was conducted using both experimental and simulation methods. In this study, bentonite clay samples with 10%, 20%, 30%, 40%, 60% and 80% of barite powder was prepared to find the optimum percent of barite powder. A HPGe detector was used to measure the attenuation coefficients at commonly used gamma ray energies of 137Cs (661.6 keV) and 60Co (1173.2 and 1332.5 keV) for all the samples. The attenuation coefficients for samples were determined by both simulation method, using the MCNP code, and XCOM database to compare with the experimental results. Simulation results were found to be in good agreements with the experimental results. The obtained results show that with increasing the percent of barite powder, radiation shielding coefficient (µ) increase while permeability coefficient becomes grater. However, according to the obtained results, the bentonite clay with 40% of barite powder is the optimum composition with a permeability factor of 8.87 × 10−11 m/s and attenuation coefficient of 16.46 m−1, 12.2 m−1 and 11.99 m−1 at 661.6, 1173.2 and 1332.5 keV energies, respectively. In addition, the results for clayey soil samples were compared to the concrete mixture. It was found that clay mixture with 40% barite powder would overcome concrete regarding gamma-ray shielding performance. As a result, the clay composite particularly due to its imperviousness and availability, seems to be an appropriate alternative for radiation shielding in radioactive waste disposal landfills.