scholarly journals Analysis on Physical and Mechanical Properties of Red Mud Materials and Stockpile Stability after Dilatation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yanbo Feng ◽  
Chao Yang

Red mud is the tailings generated from the production process of aluminum industry and is mainly stacked in open-air at present, so how to ensure the stability of red mud stockpile is very important. Regarding mud stockpile of Guizhou Aluminum Factory as the research object, this paper studies the physical and mechanical properties of Bayer red mud from wetting process, Bayer red mud from drying process, and sintering red mud through laboratory test and finally analyzes its stability under extreme rainfall condition in this region by the Geo-Studio software. The research results show that the red muds in different processes have big difference in physical and mechanical properties. The strength of sintering red mud is about 4.2 times of that of Bayer red mud from wetting process on average, and the strength of Bayer red mud from drying process is about 1.5 times of that of Bayer red mud from wetting process on average. So, the sintering red mud can be used as the subdam of red mud stockpile, to reduce the risk of collapse and dam break. The stability coefficients of the mixed stocking method under three rainfall conditions are 2.611, 2.597, and 2.631, respectively, all of which are above 1.0. It reveals that the dilatation scheme of using the sintering red mud with good engineering properties to stockpile the Bayer red mud is feasible. It can not only guarantee the safety and stability of red mud stockpiles, but also reduce the risk of red mud dam break and the capital investment of red mud yard.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 268
Author(s):  
Jitong Zhao ◽  
Huawei Tong ◽  
Yi Shan ◽  
Jie Yuan ◽  
Qiuwang Peng ◽  
...  

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.


Author(s):  
K. Z. Tilloev ◽  
S. V. Kondakov

The construction and method of calculating the stability of a crawler excavator equipped with a new working body (cone roller) are considered. The calculation is made on two working positions (longitudinal and transverse) of the excavator, provided that the excavator must apply the maximum force on the working body at an angle of 90°. The force applied by the excavator boom to the cone roller during the introduction depends on the physical and mechanical properties of the compacted soil. The calculation method differs in that during the compaction of the roadbed, the cone sinks into the ground, and the excavator tends to roll in the direction of the rear track support roller, in contrast to the traditional danger of tipping over the front support roller when working with a bucket.


2019 ◽  
Vol 945 ◽  
pp. 433-437
Author(s):  
M.D. Sokolova ◽  
A.F. Fedorova ◽  
M.L. Davydova

The present paper outlines the results of full-scale tests of climatic stability and the study of resistance to the action of hydrocarbon media of rubbers based on BNKS-18-18 (butadiene-nitrile rubber) and Hydrin T6000 epichlorohydrin rubber containing one of 6PPDstabilizerwith an aromatic amine moiety widely used in synthetic rubbers. Samples are exposed in an open ground under natural conditions of exposure to climatic external factors of Yakutsk in the Republic of Sakha (Yakutia), as well as in the oil environment of Talakanskoye field and I-50A hydraulic fluid in an unheated room. Such indexes of the samples as conditional tensile strength, elongation at rupture, hardness and degree of swelling are measured to determine the resistance of rubbers to aging after the first, third, and sixth months of exposing. The results of the study reveal the contribution of 6PPD stabilizer in maintaining the stability of the physical and mechanical properties of BNKS-18: rubber containing 6PPD has less property changes both in the open air and in hydrocarbon media compared to rubber without a stabilizer. It should be noted that the oil environment is the most aggressive environment, the swelling of rubbers in oil leads to a significant reduction in strength due to a decrease in intermolecular interaction.6PPD stabilizer occurred less effective for the rubber based on Hydrin T6000: changes in properties of the samples containing the stabilizer are larger than those of the samples without the stabilizer. However, unlike BNKS-18-18-based rubber, the swelling of rubber based on Hydrin T6000 led to the greatest stability of the physical and mechanical properties in the oil environment compared to the open air and hydraulic fluids.


2011 ◽  
Vol 331 ◽  
pp. 270-274 ◽  
Author(s):  
Yan Yan Chu ◽  
Qing Wang ◽  
Shi Zhong Cui

Abstract:Pure TiO2 water sol, pure ZnO water sol and three compound TiO2/ZnO water sols are prepared under low temperature. Then the padding and baking process is used to put the functional sol liquid on the fabric. SEM is use to analyzed the change of surface feature and the result show that all of the water sol except pure ZnO water sol liquid formed a thin film on the fiber The stability of pure ZnO water sol is the best one and the pure TiO2 water sol is the worst one at temperature of 15°C. The compound water sols stabilities are between these two water sols and with the more amount of ZnO, the stability last longer. Both mole of TiO2 and ZnO with the rate of 5 to 5 and 7 to 3 display the best antistatic behavior, but the washing fastnesses are not good. After treatment, the moisture regain displays most dramatically changes; the next one is whiteness of fabric, but the other physical and mechanical properties have a little change.


2014 ◽  
Vol 496-500 ◽  
pp. 2398-2401 ◽  
Author(s):  
Xin Zhe Li ◽  
Geng Feng Wang ◽  
Ling Cao

As a regional metamorphic rock, the engineering properties of the phyllite are rather complex. It is common that the tunnel construction safety has tremendous difficulty due to the groundwater, the initial stress state, joints, cracks and faults and other factors, so it is necessary to find an effective construction method for the construction of phyllite tunnel. To master the regular pattern of the influence of relative factors on physical and mechanical properties of phyllite is the basis to establish an effective construction method. The paper tries to analyze the influence of water and mineral composition on physical and mechanical properties of phyllite by making relevant tests on Lu Lin tunnel, and hope to give some clue to the design and construction of phyllite tunnels.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bao-tian Wang ◽  
Can-hong Zhang ◽  
Xue-lian Qiu ◽  
En-yue Ji ◽  
Wen-hui Zhang

Expansive soil experiences periodic swelling and shrinkage during the alternate wet and dry environments, which will result in severe damage to the slope stability. In this study, a promising modifier OTAC-KCl is introduced, which has a good diffusivity and is soluble in water or other solvents easily. Firstly, a reasonable combination of ameliorant 0.3% STAC and 3% KCl is chosen referring to the free swell test. Then, the best curing period, 14 days, is gotten from UCS tests. The effect of wetting and drying cycles on engineering properties of expansive soil improved by OTAC-KCl admixtures after 14-day curing is also studied accordingly. Both treated and untreated expansive soil samples are prepared for the cyclic wetting-drying tests which mainly include cyclic swelling potential and cyclic strength tests. Experimental results show that the swelling potential of expansive soil samples stabilized with OTAC-KCl is suppressed efficiently, and the untreated soil specimens will collapse when immersed in water while the treated specimens keep in good conditions. Moreover, expansive soil samples modified with 0.3% OTAC + 3% KCl show enough durability on the swelling ability, shear strength, and unconfined compressive strength, which means, that both the physical and the mechanical properties of stabilized expansive soil have been improved effectively.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3018 ◽  
Author(s):  
Mirjana Vukićević ◽  
Miloš Marjanović ◽  
Veljko Pujević ◽  
Sanja Jocković

Major infrastructure projects require significant amount of natural materials, often followed by the soft soil stabilization using hydraulic binders. This paper presents the results of a laboratory study of alternative waste materials (fly ash and slag) that can be used for earthworks. Results of high plasticity clay stabilization using fly ash from Serbian power plants are presented in the first part. In the second part of the paper, engineering properties of ash and ash-slag mixtures are discussed with the emphasis on the application in road subgrade and embankment construction. Physical and mechanical properties were determined via following laboratory tests: Specific gravity, grain size distribution, the moisture–density relationship (Proctor compaction test), unconfined compressive strength (UCS), oedometer and swell tests, direct shear and the California bearing ratio (CBR). The results indicate the positive effects of the clay stabilization using fly ash, in terms of increasing strength and stiffness and reducing expansivity. Fly ashes and ash-slag mixtures have also comparable mechanical properties with sands, which in combination with multiple other benefits (lower energy consumption and CO2 emission, saving of natural materials and smaller waste landfill areas), make them suitable fill materials for embankments, especially considering the necessity for sustainable development.


Author(s):  
A. B. Petrovsky ◽  
V. Ya. Prushak ◽  
E. A. Lutovich

The geological structure and the physical-mechanical properties of rocks composing and overlapping the Third potash formation in the areas of the mine field mine No. 4 JSC Belaruskali, which are scheduled to practice, are studied. The geological sections of the Third potash layer and its roof were built, the thickness of sylvinite and halite layers was measured, the roof falling of the rocks of the layer with a height of up to 20 m was assessed, and the type of immediate roof was determined by the composition and structure of its constituent rocks. It was established that the strength under uniaxial compression of both sylvinite and halite layers for the areas under consideration differs slightly. Therefore, to solve engineering problems of ensuring the stability of mine workings and to calculate fastening parameters, strength values averaged over the groups of layers can be used that correlate well with the percentage of weak and clay interlayers. The same applies to Poisson’s ratio, the values of which for various layers of formation are slightly different and can be taken by their averaging. It is shown that the main factor that negatively affects the strength of rocks occurring in the roof of the Third potash seam is the presence of weak and clay interlayers, which increases with depth. The introduction of the obtained results allows us to improve the calculation accuracy of securing mining parameters, to reduce the costs of their maintenance, and to improve the safety of mining operations in developing the Third potash formation in complex geological and mining conditions.


2019 ◽  
Vol 11 (1) ◽  
pp. 440-446
Author(s):  
Supandi Supandi ◽  
Zufialdi Zakaria ◽  
Emi Sukiyah ◽  
Adjat Sudradjat

Abstract This study investigates the relationship between clay minerals (kaolinite and illite) and rock properties of the claystone, including both mechanical (cohesion, friction angle, stress, and strain) and physical properties (natural water content, void ratio, and wet density), belonging to Warukin Formation of Kalimantan, Indonesia. Mineralogical characteristics of these rocks were studied using petrological and X-ray diffraction techniques, whereas the mechanical and physical properties were tested by conducting uniaxial and triaxial tests. Relationship among the variables was determined using correlation coefficients. It was observed that the mineralogy of the rocks pose strong constraints on their engineering properties. The results showed that an increase in illite content decreases cohesion, friction angle, strength, and safety factor; and increases natural moisture content, void ratio, and wet density. Although illite content of these rocks was just about 10.8% of the total minerals, it has significantly contributed to the modification of physical and mechanical properties. In contrast, kaolinite did not have a significant impact; since the correlation between various parameters was significantly low (correlation coefficient was much less, <0.3). Therefore while selecting the materials for geotechnical engineering applications, illite emerges as a safer alternative to kaolinite, especially when its concentration is less than 10.8% of the total rock mass.


2014 ◽  
Vol 60 (1) ◽  
pp. 55-75 ◽  
Author(s):  
P. Gomathi ◽  
A. Sivakumar

Abstract This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fl y ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2-100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.


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