Fine Quartz Sand Research Articles

Evaluation of the combination of desert sand and calcium sulfoaluminate cement for the production of concrete

The production of concrete requires large quantities of sand. At first sight, sand seems to be a cheap, widely available and abundant resource, however, in some regions of the earth sand is getting rare because of the high demand. An alternative might be desert sand, which is available from many sources around the world, but is not yet widely used in concrete due to its narrow particle size distribution.In this study, a new concept of combining desert sands with a binder based on calcium sulfoaluminate cements (CSA) and gypsum is tested to obtain a suitable workability and packing density and hence allows for a high sand replacement level in standard concrete. Unlike typical CSA applications, a high gypsum content is used in order to produce a large amount of ettringite, which is able to bind large quantities of mixing water.The concept is applied on a series of pastes and concretes with different standard sand replacement levels. A very fine quartz sand is used as a model desert sand. Mechanical properties (compressive and bending strength) are determined and compared to reference systems based on ordinary Portland cement (OPC). It is shown that the formation of ettringite is capable to fill the voids between the small and narrow-sized desert sand particles leading to a very dense microstructure. Drying shrinkage data show volumetric stability and reduced shrinkage. Owing to the low CSA dosage and the low carbon dioxide emissions related to CSA production, the proposed concrete mixtures can be regarded as eco-friendly.

Permeability measurement and discovery of dissociation process of hydrate sediments

The study on the permeability of methane hydrates in fine quartz sands contributes to the accurate prediction of gas/water production and can effectively express the characteristics of fluid migration. In this study, the water effective permeability (kw) of methane hydrates in three fine quartz sands containing various hydrate saturation (SH) were carried out under steady water injection and production. Experimental results indicated that the effect of particle sizes on kw was significant even though the difference in the average particle size of three fine quartz sands was relatively limited. The differential pressure of the hydrate sediments was completely recorded during permeability measurement, and the stabilization and decomposition process of hydrate could be clearly represented by differential pressure. The kw increased rapidly with the decomposition of hydrate and the appearance of flow channel in the hydrate sediments. Hydrate dissociation process was recorded in situ by Cold Field Emission Scanning Electron Microscopy (CFE–SEM), the dissociation of hydrates in pore space was clearly visible, and the hydrates in pore space were first dissociated into many small regions. A new reduction model between water relative permeability (krw) and SH was proposed on the basis of experimental results, and the experimental data fitted well with hydrates occupying pore centers. The effect of particle sizes on krw was eliminated, the Archie saturation exponent n tended to increase with the increase of SH, and n was recommended between 20 and 30.

Influence of mixture composition on fresh concrete workability for ballastless track slabs

There are several factors that affect the fresh concrete workability: water demand and composition of Portland cement, properties of fine and coarse aggregates, presence of superplasticizer and others admixtures, etc. Influence of quantity and fineness of ground quartz additives as well as polycarboxylate-based superplasticizer amount on workability of fresh concrete was studied in the paper. The properties of fresh mixture (slump) and hardened concrete (compressive strength at the age of 24 hours, 28 and 360 days) were estimated. Enhancing the fresh concrete workability using fine ground quartz sand was stated. Savings of superplasticizer per 1 m3 of slab concrete and 1 km of the ballastless track were calculated.

Grouting of Waste of the Baikal Pulp and Paper Mill to Reduce the Technogenic Impact to the Baikal Lake Ecosystem

Research is devoted to the problem of recycling waste of the Baikal Pulp and Paper Mill, whose activity has caused serious damage to the ecological environment of Lake Baikal and its environs. Grouting waste production is currently the most effective possible decision to the problem of pollutants, such as sludge-lignin and ash, in water objects and groundwater. The results on the grouting of liquid and solid waste from the Baikal Pulp and Paper Mill, represented by sludge lignin and ash, are presented. Cement, liquid glass, colloidal silica, ammonium persulfate, hydrogen peroxide were used as the main hardeners. Samples were formed by mixing the original waste with astringent. The strength in time, shrinkage, resistance to water were studied. Samples formed on the basis of colloidal silica solution have a maximum uniaxial compressive strength of 0.4 - 0.5 MPa, on the basis of liquid glass—0.2 - 0.3 MPa. Adding fine sand increases the strength by 1.5 - 1.7 times. Samples based on ammonium persulfate and hydrogen peroxide do not have sufficient strength. Adding fine quartz sand increases the strength up to 1.0 - 1.2 MPa.

Experience in determining viscosity of soil on the basis of experimental studies

Modern construction is developing at enormous speed, which leads to the need for more in-depth study of the physical and mechanical properties of soils in general, and clay soils in particular, in order to make rational use of their natural properties in the construction and design of foundations, foundations and soil structures. In this regard, recently, special attention has been paid to the study of the rheological properties of soils. One of the main rheological parameters of the soil is its viscosity. To determine the coefficient of viscosity of the soil in this study, a simple shear device was used. An artificially created sandy loam consisting of fine quartz sand (60% by weight) and clay particles (40% by weight) was adopted as the test soil. In the course of the study, characteristic graphs of the dependence of tangential stresses on shear deformation at different test speeds were obtained. Also, taking the Newton equation as a basis, the average value of the soil viscosity coefficient was determined for each shear rate.

CEMENT STONE STRUCTURE COMPACTION WITH COMPOSITE BINDER

The aim of the paper is to improve the strength properties of cement stone via control for structure formation. The composite binder composition includes the type CEM I 42.5N (58–70%) Portland cement, active silica additive (25–37%), quartz sand (2.5–7.5%) and limestone crushed waste (2.5–7.5%). The optimum technology of mechanochemical activation is proposed for the cement stone. The optimization of the structure formation process is provided by the mineral-mineral modifier, crushed together with Portland cement in a planetary mill to a specific surface of 550 m2/kg. The amorphous phase of silicon dioxide in the composition of the modifier intensifies the calcium hydroxide binding forming during alite hydration. It contributes to the growth in low-basic calcium silicate and lowers the cement stone basicity, while reducing the amount of portlandite. The crystalline phase of β-quartz silicon dioxide plays the role of crystallization centers new formations and the cement stone microstructure compaction. Limestone particles contribute to the formation of calcium hydrocarbonate and act as a microfiller together with fine ground quartz sand clogging the pores in the cement stone.

Modified fine-grained concretes based on highly filled self-compacting mixtures

In this article the results of study of rheo-technological characteristics of cement-carbonate suspensions and physical and mechanical characteristics of cement composites from highly filled self-compacting mixtures are presented. The optimal dosage of polycarboxylate superplasticizer (Melflux 5581 F) and rheologically active mineral filler (microcalcite) in cement-mineral suspensions when developing self-compacting fine-grained concrete mixtures is defined. The water demand of fine natural quartz sands using the methodology of Skramtayev and Bazhenov is studied. The compositions of self-compacting fine-grained concrete mixtures of workability class SF1 with fine natural quartz sand are developed. High physical and mechanical characteristics of fine-grained concretes from highly filled self-compacting mixtures are fixed: density in normal humidity conditions at the age of 28 days up 2393 kg/m3; bending and compressive strength at the age of 28 days up 14.9 and 115.8 MPa, respectively.

N2O hydrate formation in porous media: A potential method to mitigate N2O emissions

Increasing nitrous oxide (N2O) emissions and their potential impacts on the ozone layer are of worldwide concern. Hydrate-based sequestration technology is considered to be a promising method for N2O control. This study investigated the conditions required for N2O sequestration through forming hydrates. Magnetic resonance imagining (MRI) was used to capture and quantify N2O hydrate formation in porous media simulated by fine quartz sands. The effect of the sequestration conditions on hydrate formation were investigated, involving pressure (1.5, 2, and 2.5 MPa), temperature (275.15, 276.15, and 277.15 K) and initial water saturation (25.06, 33.23, 42.13, and 50.81%). The results indicated the inhomogeneous formation and distribution of N2O hydrates in pore spaces. Initial water saturation and pressure were found to significantly impact the hydrate distribution during the initial formation stage. Moreover, N2O hydrates formed more rapidly in sediments with a lower water saturation and temperature, indicating that sufficient contact between gas and water and a higher driving force are crucial for abundant hydrate formation. A higher initial water saturation could help improve the sequestration efficiency, which would play a crucial role in locating the sequestration site. This work could provide some insights of the mechanism of N2O sequestration via hydrate formation in sediments, making contributions to potential applications in field tests.

Mechanical behaviour and microstructure of an artificial stone slab prepared using a SiO2 waste crucible and quartz sand

This paper presents an experimental investigation of the production of a high-quality artificial stone slab using a SiO2 waste crucible. A fine SiO2 waste crucible powder and quartz sand were mixed with unsaturated polymer resin (UPR) as a binder, and all samples of artificial stone slabs were prepared using vibratory compaction in a vacuum environment. The properties of the artificial stone slabs as a function of different coupling agent contents, UPR contents, compaction times and curing time were studied using compression, three-point bending, bulk density and water absorption tests. The structural features of the samples were also characterized. Compaction served to prevent the formation of pores between particles; however, excessive compaction crushed the particles. The compressive and flexural strength of the samples increased as the curing time increased. Optimal proportions of the contents of the UPR and coupling agent achieved the most cost-effective production parameters. The artificial stone slabs obtained in this work have high compressive and flexural strengths of 170.9 and 73.5 MPa under a compaction time of 3 min and a curing time of 60 min, which are superior to natural construction slab and most artificial stone slabs.

Testing the auto‐abrasion hypothesis for dust production using diatomite dune sediments from the Bodélé Depression in Chad

AbstractThis study examines the role of quartz sand in the production of dust using mixtures of quartz sand from the Sahara and diatomite aggregates from the Bodélé Depression in Chad. An aeolian abrasion chamber is used to reproduce the physical processes of aeolian abrasion and test the hypothesis that the breakdown of saltating diatomite flakes as they collide in saltation, and with the surface, is the most prolific mechanism of dust production (auto‐abrasion). This hypothesis is tested against the competing hypothesis that a hard, higher‐density quartz sand impactor is required to abrade fine‐grained sediments to generate dust. The results show that dust can be produced by a mixture of saltating diatomite and quartz sand particles. However, quartz sand is not required for saltating aggregates to produce dust. Indeed, these results, which used a mixture of very coarse‐grained aggregate (1 to 2 mm diameter) with fine quartz sand, indicate that the addition of quartz sand can decrease dust production. For a very coarse aggregate (1 to 2 mm), a pure diatomite aggregate produced the most dust, although using a coarse‐grained aggregate (0·5 to 1·0 mm) with a mixture of 20% quartz and 80% aggregate was found to produce the most dust overall. The results of this study confirm the auto‐abrasion hypothesis for the breakdown of diatomite particles in the Bodélé Depression, which is the single biggest source of atmospheric mineral dust on Earth.

Sulfur and iron influence the transformation and accumulation of mercury and methylmercury in the soil-rice system

Much attention is directed to the accumulation of mercury and methylmercury (MeHg) in rice grown on Hg-contaminated paddy fields, since they pose a risk to the health of both people and wildlife. Ultimately, measures to control the accumulation of Hg and MeHg in rice should become a key focus of research on this topic. The objective of this study is to test whether Hg and MeHg accumulation are reduced in polished rice when iron and sulfur are added together to the paddy fields during the cultivation of rice. In this experimental study, rice plants were grown in pots amended with sulfur and iron. Rice paddy soil contaminated by mercury chloride in the sewage water used for irrigation was simulated in this experiment by Hg-contaminated soil. The total mercury (THg) content added to the soil as mercury chloride reached 120 mg kg−1 as the weight of the dry soil. Two levels of iron (0 and 200 mg kg−1 as FeCl2) as well as sodium sulfate and cysteine (Cys) were added via watering. Two 30-day rice seedlings were transplanted into a root-bag (20 cm long, 12 cm wide), filled with fine quartz sand and cultured in a plastic barrel filled with 4.5 kg of waterlogged soil. When the rice plants matured, samples were taken. The addition of iron and sulfur to the Hg-contaminated paddy soil increased the dry weight of rice grains. The THg and MeHg mainly concentrated in the upper soil layer, and the concentrations of MeHg in the treatments with iron and sulfur were especially higher than that of the control. The addition of iron, sulfate and iron, and cysteine and iron decreased THg concentrations in polished rice by 17.7, 38.3, and 21.3%, respectively. The addition of iron, sulfate and iron, or cysteine and iron decreased the MeHg concentration up to 29.9, 36.4, and 48.2% in polished rice, respectively. Thus, we infer that the coupling of sulfur and iron (II) plays an important role in decreasing the accumulation of MeHg in polished rice. The addition of iron and sulfur together decreased the concentration of THg and MeHg in polished rice. These results can help control concentration levels of MeHg in rice; however, further study of the mechanism of the interaction of sulfur and iron in Hg-contaminated paddy soil should be conducted.

The influence of small-scale interlayer heterogeneity on DDT removal efficiency for flushing technology

With an aim to investigate the influence of small-scale interlayer heterogeneity on DDT removal efficiency, batch test including surfactant-stabilized foam flushing and solution flushing were carried out. Two man-made heterogeneous patterns consisting of coarse and fine quartz sand were designed to reveal the influencing mechanism. Moreover, the removal mechanism and the corresponding contribution by foam flushing were quantitatively studied. Compared with surfactant solution flushing, the DDT removal efficiency by surfactant-stabilized foam flushing increased by 9.47% and 11.28% under heterogeneous patterns 1 and 2, respectively. The DDT removal contributions of improving sweep efficiency for heterogeneous patterns 1 and 2 by foam flushing were 40.82% and 45.98%, and the contribution of dissolving capacity were 59.18% and 54.02%, respectively. The dissolving capacity of DDT played a major role in DDT removal efficiency by foam flushing under laboratory conditions. And the DDT removal contribution of significant improving sweep efficiency was higher than that of removal decline caused by weak solubilizing ability of foam film compared with solution flushing. The obtained results indicated that the difference of DDT removal efficiency by foam flushing was decreased under two different heterogeneous patterns with the increase of the contribution of improving foam flushing sweep efficiency. It suggested that foam flushing can reduce the disturbance from interlayer heterogeneity in remediating DDT contaminated heterogeneous medium.

Use of alternative waste materials in producing ultra-high performance concrete

In a corrosive environment similar to that of the Arabian Gulf, use of high-performance concrete is one of the options to ensure a target service life of concrete structures. However, in absence of good quality coarse aggregates, it is a challenging task to produce high-performance concrete. Recently, the possibility of producing ultra-high-performance concrete (UHPC) has been widely reported in the literature. UHPC is produced without coarse aggregates at very low water to cementitious materials ratio, high amounts of cement, mineral admixtures, and superplasticizer along with fine quartz sand as aggregate, quartz powder as micro-filler, a nd steel fibres for fracture toughness. In the present work, an effort was made to utilize local waste materials as alternative mineral admixtures and local dune sand as aggregate in producing different UHPC mixtures without addition of quartz powder. The mechanical properties, shrinkage, and durability characteristics of the UHPC mixtures were studied. Test results indicate that it is possible to produce UHPC mixtures using alternative waste materials, which would have targeted flow, strength, toughness, and resistance against reinforcement corrosion. The information presented in the paper would help in optimum selection of a mixture of UHPC considering the availability of local materials, exposure conditions and structural requirements.

Experimental Study on Influence of Fly Ash on Properties of Gold Tailings Reactive Powder Concrete

In this study, the tail ore was be used as a fine aggregate of RPC or gelled material, because it is rich of silicon and its particle size is peculiar. Through choosing the raw materials reasonably, optimizing the water/cement ratio, water reducing agent dosage and mineral admixture content, the economical RPC was be prepared with tail sand instead of the grinding fine quartz sand, mixing different properties of mineral admixtures.

A Multi-Functional Penta-Needle Thermo-Dielectric Sensor for Porous Media Sensing

There is growing interest in multifunctional sensors that expand sensing capabilities, especially for environmental measurement needs. This paper aims to develop a multifunctional penta-needle thermo-dielectric sensor (MPTDS) by coupling an electromagnetic (EM) sensor for determining water content with a penta-needle heat pulse probe (PHPP) for determining thermal properties. The thermal properties were inverse fit to the measured temperature rise at four surrounding thermistor needles from an 8-s heat pulse on a central heater needle. The dielectric permittivity was obtained from an impedance measurement made on the heater needle and two adjacent thermistor needles, leading to water content estimates. To determine water content and thermal properties for porous media, a two-step permittivity calibration and an in-situ effective needle spacing calibration were also made. The prototype MPTDS was evaluated in fine quartz sand across a range of water contents from dry to saturated to determine dielectric permittivity, thermal conductivity, and thermal diffusivity, followed by the accurate calculation of water content and soil heat capacity. The limited comparison here demonstrates substantially improved substrate water content determination accuracy from the EM sensor (RSME = 0.012 cm3/cm $^{3})$ when compared with heat-pulse estimates (RSME = 0.042 cm3/cm3).

Investigation of using recycled powder from waste of clay bricks and cement solids in reactive powder concrete

Recycled powder, produced from the construction and demolition wastes, contains unhydrated cement particles. It can reduce environment pollution to use recycled powder as a cementing material. It is investigated to use recycled powder to partially replace silica fume or cement in Reactive Powder Concrete (RPC) to develop environmentally-friendly and cost-saving RPC mixture with high performance. Properties of the recycled powder are tested firstly. And according to maximum packing theory, the RPC mix with the recycled powder is designed. Influences of the fine aggregate, quartz and natural sand, on the RPC are investigated. The water-cementitious materials ratio (w/cm) for RPC mixes with the recycled powder are studied and selected. The recycled powder is used to replace the silica fume and cement in RPC respectively, and influences of the replacement ratio on the flowability, strength and durability are investigated. The standard curing is used for all the tests instead of steam curing normally required for RPC. Considering the flowability, strength, durability, cost and environmental savings, it is suggested that the recycled powder can be used to replace the silica fume and cement in RPC partially, and natural sand can be used instead of quartz. Additionally, influences of GGBFS powder on RPC mix with the recycled powder are investigated.

Encapsulation of light hydrophobic liquids with fine quartz sand: Property based characterization and stability in aqueous media with different salinities

A novel method for capturing oil slicks in aquatic environments with granular solids was investigated. Experiments were conducted with pure hydrophobic liquids (HL) (decane, tetradecane, hexadecane, benzene, toluene, ethylbenzene, and m-xylene) representing the main groups in crude oil (alkanes and aromatics), and fine quartz sand (passing sieve no. 40 with 0.425mm openings). The amounts of HL captured in the HL/sand globules were correlated with the properties of HLs. Positive correlations between the aggregated HL volume with density and surface tension were observed. Aggregation number (AN) is introduced to estimate the amount of HL aggregated with fine quartz sand (using 0.5mL HL and 1.0g sand; floating HL layer thickness to particle diameter ratio >4:1). Change in the aggregated HL volume over time was examined and dissolution rate constants were obtained. Benzene and toluene completely dissolved from the aggregated globules within 3–4 days after the aggregation, while the other HLs exhibited relatively small change in the globule size over time. Salinity of water did not affect the aggregation rates of HLs but slightly decreased the dissolution rate constants for some HLs.

Cadmium removal from urban stormwater runoff via bioretention technology and effluent risk assessment for discharge to surface water

Bioretention technology, a low-impact development stormwater management measure, was evaluated for its ability to remove heavy metals (specifically cadmium, Cd) from urban stormwater runoff. Fine sand, zeolite, sand and quartz sand were selected as composite bioretention media. The effects of these materials on the removal efficiency, chemical forms, and accumulation and migration characteristics of Cd were examined in laboratory scale bioretention columns. Heretofore, few studies have examined the removal of Cd by bioretention. A five-step sequential extraction method, a single-contamination index method, and an empirical migration equation were used in the experiments. The average Cd removal efficiency of quartz sand approached 99%, and removal by the other media all exceeded 90%. The media types markedly affected the forms of Cd found in the columns as well as its vertical migration rate. The Cd accumulated in the four media was mainly in residual form; moreover, accumulation of Cd occurred mainly in the surface layer of the bioretention column. The migration depth of Cd in the four media increased with elapsed time, in the following sequence: zeolite>quartz sand>fine sand>sand. In contrast, the migration rate decreased with elapsed time, and the migration rate of Cd was lowest in sand (0.015m per annum over the first ten years). The comprehensive risk index analysis indicated that the risk arising from Cd discharge to surface water was “intermediate”, and that the degree of risk was lowest in sand, then quartz sand, zeolite, and fine sand in sequence. These results indicate that the adsorption and accumulation of Cd in the four media are more significant than the migration of Cd. In addition, the results of Cd risk assessment for the effluent indicate that each of the four media can serve as long-term adsorption material in a bioretention facility for purifying stormwater runoff.

Tillites at the base of the Vendian Taseeva Group in the stratotype section (Siberian craton)

Isolated lenses of diamictites laying discordantly over the Late Riphean (Cryogenian) Kirgitei Formation were found in the immediate vicinity of the Vendian Taseeva Group stratotype in the Taseeva River valley and assigned to the Shishina Member a few meters in visible thickness. The Shishina diamictites are, likely, of glacial origin as they (i) lie at the base of the Vendian section, (ii) consist of unsorted dolomitic clasts from fine gravel to more than 0.5 m boulders suspended in a mud matrix, and (iii) show glacial striation on clasts. The glacial origin is further supported by the morphology of stones, which resemble a smoothing iron or a bullet, with a swelly top, a flat bottom, and a steeply cut rear and form clusters produced by disintegration of larger boulders. The stones bear signatures of cleavage, cracks, grooves, and striation on the faces, while the matrix looks undeformed. The Shishina Member has no genetic relation with the underlying Kirgitei Formation but rather correlates sedimentologically with the Ulyakha Member tillites at the base of the Vendian Marnya Formation (Oselok Group) in the Sayan foothills. The Shishina Member stones may derive from the Late Riphean (Cryogenian) Dzhura Formation exposed 4 km downstream of the site along the Taseeva. They occur near the base of the Aleshinsky Formation (lowermost unit of the Taseeva Group) of cross-bedded glaciofluvial sandstone, gravelstone, conglomerate, and sandy gravel mixtite transported from east to west (from the Siberian Craton interior to its margins) and deposited in channel bars or as gravel lags. The lower member of the Aleshinsky Formation comprises two associations of clasts: (i) coarse quartzose sand and gravel and (ii) fine and medium quartz and lithoclastic sand. Rocks in the former are well rounded, with traces of wind erosion, while the latter association is composed of mechanically eroded angular material transported to short distances from a metamorphic and metasedimentary source on the Craton margin. The Aleshinsky clastics have their composition and grain size patterns similar to those of the glaciofluvial Plity, Nersya, and Kedrovy members of the Marnya Formation in the Sayan area. According to sedimentological evidence, the Shishina diamictites are tillites identical to the Ulyakha moraine at the base of the Sayan Oselok Group and may be a missing link in the Taseeva Group stratigraphy.

Granular encapsulation of light hydrophobic liquids (LHL) in LHL-salt water systems: Particle induced densification with quartz sand.

Addition of granular materials to floating crude oil slicks can be effective in capturing and densifying the floating hydrophobic phase, which settles by gravity. Interaction of light hydrophobic liquids (LHL) with quartz sand was investigated in LHL-salt water systems. The LHLs studied were decane, tetradecane, hexadecane, benzene, toluene, ethylbenzene, m-xylene, and 2-cholorotoluene. Experiments were conducted with fine quartz sand (passing sieve No. 40 with openings 0.425 mm). Each LHL was dyed with few crystals of Sudan IV dye for ease of visual observation. A volume of 0.5 mL of each LHL was added to 100 mL salt water (34 g/L). Addition of one gram of quartz sand to the floating hydrophobic liquid layer resulted in formation of sand-encapsulated globules, which settled due to increased density. All LHLs (except for a few globules of decane) formed globules covered with fine sand particles that were heavy enough to settle by gravity. The encapsulated globules were stable and retained their shape upon settling. Polarity of hydrophobic liquids as the main factor of aggregation with minerals was found to be insufficient to explain LHL aggregation with sand. Contact angle measurements were made by submerging a large quartz crystal with the LHL drop on its surface into salt water. A positive correlation was observed between the wetting angle of LHL and the LHL volume captured (r = 0.75). The dependence of the globule density on globule radius was analyzed in relation to the coverage (%) of globule surface (LHL-salt water interface) by fine quartz particles.