Different Types Of Sand Research Articles

Investigation of the Mechanical Properties of Engineered Cementitious Composites with Low Fiber Content and with Crumb Rubber and High Fly Ash Content

Engineered cementitious composites (ECCs) are a type of micromechanically-designed cementitious composite reinforced with a moderate volume fraction of short fiber, typically 2% by volume. ECCs form steady-state multiple cracking that considerably improves the tensile strength and ductility of traditional concrete. In this study, the properties of matrix and the interface of ECCs were tailored through the use of crumb rubber, different types of sand, and different replacement levels of cement with fly ash. The study examined the effect of sand replacement with crumb rubber (20% by volume), two types of river sands (coarse and fine), increasing the content of class F fly ash (up to 75% cement replacement), and low fiber content (1.75%) on the mechanical properties of ECCs. Compressive strength, uniaxial tensile, and third-point bending tests were performed to characterize the properties of ECC mixes. Experimental results demonstrated that increasing fly ash content and using crumb rubber favored ductility of the composites. However, higher fly ash contents and a low water-to-binder (W/B) ratio produced lower strengths as these limited the pozzolanic reaction of fly ash making it act partially as a filler. While incorporation of crumb rubber showed adverse effects on the tensile strength of ECC materials (up to 26% decrease), the tensile ductility of ECC materials improved significantly (up to 434% improvement). Moreover, the implementation of different types of sand produced minor effects on the mechanical properties of ECCs. Overall, a tradeoff between the strength and ductility of the composites was detected, which highlights the implications of matrix/interface tailoring in the overall performance of ECC.

Predicting the thermal behaviour of sands considering its moisture content and grain size with applications to geothermal heat pump installations

Space conditioning has one of the highest end-use service demands in the building sector. To avoid negative effects on the energy system and the environment, efficient energy sources and technologies must be implemented to provide future heating and cooling requirements. Geothermal heat pump systems (GHPS) are one of the technologies with highest thermodynamic and cost performance; nevertheless, its performance highly depends on local geological characteristics. In this study, a thermodynamic assessment of different types of sands, that could potentially be used as energy sources for GHPS in dry regions, has been conducted. The experiment focuses on understanding the thermal behaviour of five dry sand samples with different standard sieve sizes according to ASTM designations (Nos. 50, 45, 30, 16, and 14) and moisture content capacities. Based on the obtained data, a mathematical model to predict sand temperatures has been derived considering grain size, shape and moisture content. Compared to previous models, our results show that the developed model computed more accurate approximations compared to actual temperatures, providing a robust thermal behaviour model of dry regions’ sands that could be used in building simulation tools more effectively.

On the small-strain stiffness of polypropylene fibre-sand mixtures

In this study, the effect of fibre reinforcement on the small-strain shear modulus (Gmax) of sandy soils is investigated. A comprehensive set of 47 specimens composed of different types of sand reinforced with variable percentages of polypropylene fibres were tested using a Hardin-type resonant column apparatus embedded with bender element inserts to study the effect of fibre inclusion and content on the Gmaxof sands with different particle shapes and gradations. Accordingly, an expression of Gmaxfor sands, previously proposed by the last two authors and their colleagues, was systematically modified in this study to include the effect of fibre content to estimate the small-strain shear modulus of fibre reinforced sands. An additional set of dynamic tests was performed to verify the newly proposed expression. It was shown that the newly developed expression can predict the Gmaxof sand-fibre mixtures with an accuracy of around ±20%, with the error being limited to ±10% in the majority of the cases.

Effect of using Different Types of Sand on Workability, Mechanical and Durability Performance of High Strength Concrete

Effect of using Different Types of Sand on Workability, Mechanical and Durability Performance of High Strength Concrete

Generation of realistic sand particles with fractal nature using an improved spherical harmonic analysis

Based on X-ray micro-computed tomography images of natural sand particles, a set of spherical harmonic descriptors and an associated fractal dimension were introduced to characterise the multi-scale particle morphology. Based on the statistics of the fractal dimensions for different types of sands, this study proposed a practical method to generate realistic sand particles with the major morphological features of their mother sands. To validate this method, two virtual sand assemblies were generated, whose 3D printing and shape parameters were compared with those of real sand particles. Furthermore, these generated particle morphologies were incorporated into DEM simulations of granular column collapse.

Prospects for using broken stone quarries waste

The analysis of the production of broken stone materials shows that the processing enterprises of this product have problems with the storage of waste product. The dumps of waste cover huge areas of land suitable for agriculture use. The accumulation of waste also affects the environment. Its accumulation occurs due to the imperfect technology of waste products recycling. Granite screenings is the waste of this production. The introduction of modern waste recycling technologies allows to get washed sand, which becomes a competitive product. The paper analyzes the granulometric composition of different types of sand, compares granulometric composition of different types of sand and the directions of use of sand in various industries, also it highlights construction and road works. In general, the paper is dedicated to the production of granite sand. The physical and mechanical properties of granite sand and its fractional composition are described. A comparison of the granulometric composition of granite sand with an «ideal» granulometric curve of filler with a grain size of 2.5 mm (by Fuller) is made. The analysis shows that the curve for washed sand closely approximates to the «ideal» curve. This fact indicates that granite sand has a wide range of applications as filler for production plaster and building mortars. According to quality indicators, washed sand meets European quality standards. The widespread use of granite screenings makes it possible to reduce the environmental impact and improve the technical and economic performance of enterprises that are engaged in mining of broken stone.

Solar Reflector Materials Degradation Due to the Sand Deposited on the Backside Protective Paints

Concentrating solar power (CSP) technologies are foreseen to be a crucial actor in the future renewable energy mix. Soil accumulation on the optical surfaces of CSP plants involves significant expenses of the operation and maintenance activities because a high cleanliness level is required to achieve proper plant revenues. Normally, only the front side of the solar reflectors is cleaned to reflect the maximum possible amount of direct solar radiation towards the receiver. However, soil deposited on the backside of the reflector could provoke degradation and might need to be considered in the cleaning strategy. As this possible degradation has never been studied, this work is dedicated to assess if the backside of reflectors should be regularly cleaned. The influence of the sand in the possible paint degradation depends on its chemical composition and the weather conditions. Therefore, several climatic conditions of artificially soiled reflector samples with different types of sand were simulated in accelerated aging tests. Concerning the results obtained, the ambient conditions simulated by the damp heat and thermal cycling tests were the only ones that produced a significant degradation of the backside paints. Also, the sand from Ouarzazate was responsible for higher deterioration.

Effects of Resin Coated Sand Mixture on Bending Strength and Cost

This research proposed a method to find out the relationship between bending strength of resin coated sand and the proportion of different types of sand and resin. It was figured out that Central Composite Design (CCD) was suitable to be used to save the number of experimental runs. Then, backward elimination regression analysis was used to determine the relationship equation of bending strength and proportion of different types of sand and resin. Next, optimization technique was applied to determine the optimal new setting, which provided any targeted level of bending strength with the minimal total cost of sand and resin. The results showed that the experimental results obtained from the CCD experiments provided the regression model, which had less than 6% error from the actual bending strength value. With this proposed method the total cost of sand and resin was reduced by 28.6% on average and it also provided the bending strength on any required target level.

A Comparative Numerical Study on Soil–Geosynthetic Interactions Using Large Scale Direct Shear Test and Pullout Test

The direct shear test and the pullout tests are two widely used test procedures for determining the properties of the soil–geosynthetic interface. It is evident from the previous literature that the interface properties obtained from these tests differ considerably. In the present study, an attempt has been made to compare the interface properties obtained from the direct shear test and the pullout tests using the numerical simulations. A nonwoven polypropylene geotextile was used in the study. Three different types of sands with different fines content were considered. The analyses were carried using finite element package PLAXIS2D in two dimensional frameworks. Initially, the numerical model was validated with the existing literature and the validated model was used to study the interface behaviour of the sand-geotextile interface. The results revealed that the interface properties obtained from the direct shear test and the pullout tests vary significantly. The presence of the fines content in the soil reduces the frictional resistance of the soil-geotextile interface. The interaction ratio value was found to vary between 0.67 and 0.97 for different types of sand. The friction coefficient of the pullout test was about 50% of the friction coefficient value obtained from the direct shear test. The friction angles obtained from the pullout test were found to vary between 30 and 50% of the direct shear tests. However, the apparent cohesion of the pullout test was found approximately four times the cohesion value obtained from the direct shear test.

A compression model for sand–silt mixtures based on the concept of active and inactive voids

A compression model for sand–silt mixtures is needed in geotechnical engineering, for example in the analysis and prediction of deformation of levees and embankments due to internal erosion. In this paper, we introduce a novel concept of dividing the voids of a granular material into two hypothetical fractions: active and inactive voids. The active voids are kinematically available to the compression process. The inactive voids are kinematically unavailable to the compression process. The volume of active voids is dependent on the initial density and effective stress level. The volume of inactive voids is dependent on the amount of fines in the mixture. The current paper considers 1-D and isotropic compression behavior of sand–silt mixtures at stress levels lower than 2 MPa, so no substantial particle breakage is expected to occur. To successfully predict the void ratio for a sand–silt mixture during compression loading, we need (1) a mathematical expression for the evolution of the active void ratio during compression and (2) a relationship between the inactive void ratio and fines content of the mixture. For sand–silt mixtures with any amount of fines, the proposed model requires five material parameters, which are determined from two compression tests, and four minimum void ratio tests on sand–silt mixtures with different fines content. The performance of the proposed model is verified for six different types of sand–silt mixture with various fines contents, by comparing the predicted void ratios with the measured data from the experiments. The comparisons show a good agreement between the predictions and the measured data and prove the suitability of the proposed model for the prediction of compressibility of sand–silt mixtures with any amount of fines.

Effect of Particle Morphology, Compaction, and Confinement on the High Strain Rate Behavior of Sand

The effect of grain shape, size distribution, intergranular friction, confinement, and initial compaction state on the high strain rate compressive mechanical response of sand is quantified using Long Split Hopkinson Pressure Bar (LSHPB) experiments, generating up to 1.1 ms long load pulses. This allowed the dynamic characterisation of different types of sand until full compaction (lowest initial void ratio) at different strain rates. The effect of the grain morphology and size on the dynamic compressive mechanical response of sand is assessed by conducting experiments on three types of sand: Ottawa Sand with quasi-spherical grains, Euroquartz Siligran with subangular grains and Q-Rok with polyhedral grain shape are considered in this study. The adoption of rigid (Ti64) and deformable (Latex) sand containers allowed for quasi-uniaxial strain and quasi-uniaxial stress conditions to be achieved respectively. Additionally, the effect of intergranular friction was studied, for the first time in literature, by employing polymer coated Euroquartz sand. Appropriate procedures for the preparation of samples at different representative initial consolidation states are utilized to achieve realistic range of naturally occurring formations of granular assembly from loose to dense state. The results identify material and confining sample state parameters which have significant effect on the mechanical response of sand at high strain rates and their interdependency for future integration into rate dependent constitutive models.

Transport behavior of the pharmaceutical compounds carbamazepine, sulfamethoxazole, gemfibrozil, ibuprofen, and naproxen, and the lifestyle drug caffeine, in saturated laboratory columns

Despite the large number of pharmaceutically active compounds found in natural environments little is known about their transport behavior in groundwater, which is complicated by their wide range of physical and chemical properties. The transport behavior of five widely used and often detected pharmaceutical compounds and one lifestyle drug has therefore been investigated, using a set of three column experiments. The investigated compounds were the anticonvulsant carbamazepine, the lifestyle drug caffeine, the antibiotic sulfamethoxazole, the lipid regulator gemfibrozil, and the nonsteroidal anti-inflammatories ibuprofen and naproxen. The columns were filled with three different types of sand. The substrates consisted of artificially prepared iron-coated sand, artificially prepared organic carbon sand (with 5% leaf compost), and natural aquifer sand from Long Point, Ontario (Canada). The experiments were conducted simultaneously under the same hydraulic conditions and with the same input solution of about 1μg·L−1 of each compound. The transport behavior of the organic compounds differed significantly between both the different columns and the different compounds. A strong correlation was observed between the retardation factors for carbamazepine, gemfibrozil, and ibuprofen and the organic carbon content of the substrate. While the retardation increased with increasing organic carbon content, no direct relationship was observed between the organic carbon content and the removal of these compounds. In contrast, the retardation factors for sulfamethoxazole and naproxen showed no correlation with the organic carbon content but these compounds were significantly removed in the presence of organic matter. The influence of the Fe3+ surfaces in the iron-coated sand was less significant than expected, with all compounds except for sulfamethoxazole having retardation factors <1.8. Caffeine was so strongly removed during transport through those substrates containing organic carbon that no reliable retardation factor could be determined.

Study of the combined effect of different types of sand on the characteristics of high performance self-compacting concrete

The characteristics of self-compacting concrete at high performance (SCCHP) made with different types of sand were investigated. Three types of sands were used separately and in binary combinations: river sand (RS), dune sand (DS) and crushed sand (CS). The introduction of CS and DS aims to valorize the by-products of crushing and local materials for the formulation of the SCCHP. Different compositions containing RS, CS, DS and their binary mixtures were experimentally studied. First we started by the measurement of loose compactness’s of different combinations of aggregates and concretes. Thereafter, the SCCHPs were characterized by different test methods such as (slump flow test, L-box test and sieve stability test). Finally, the SCCHPs are subjected to mechanical testing. The obtained results proved that the binary combinations of different sands have a positive effect on the compactness. However, they do not give the best results in rheological and mechanical characteristics of the SCCHP. The results obtained by studying SCCHPs formulated by the addition of CS to the RS with moderate contents (≤40%), and by the addition of DS to the RS at low contents (≤20%) were very interesting from an economic, environmental or technological point of view.

Practical technical solution for clay-contaminated sands used in concrete

Sand, whether natural or manufactured, shows in many instances varying degrees of high levels of clay contamination. This fact is encountered in different parts of the globe and can lead to serious problems in adjusting concrete mix proportions and requiring high water to cement ratios and/or high dosages of superplasticizers without necessarily meeting the workability requirements, even when the sand is previously washed with fresh water. In this paper, different types of sand from the Gulf Cooperation Council (GCC) region are being screened, analysed for their clay contents and consequent effects on plastic concrete quality. A technical solution is being proposed based on engineered superplasticizers. A testing protocol has been established to verify the robustness of optimized mix designs demonstrating the performance of the admixture in terms of initial and extended workability. In particular, it will be demonstrated that the customized concrete admixtures constitute by themselves a stand-alone answer to the usage of clay-contaminated sands in concrete.

Constitutive modelling of sand: a progressive calibration procedure accounting for intrinsic and stress-induced anisotropy

The recently developed constitutive model for sand, designated as Ta-Ger sand (as described by the present authors in another recent paper), is reformulated to account for intrinsic and stress-induced anisotropy. The model combines features of bounding surface plasticity and Bouc–Wen type hysteresis, and incorporates Rowe's dilatancy theory and the critical state concept. A physically motivated calibration methodology is developed with the aim to reduce the number of internal model parameters by expressing them as functions of four state variables: (a) Bolton's relative density index, Ir, for measuring the ‘distance’ between the current stress state and the critical state; (b) cumulative absolute deviatoric strain increment for controlling the evolution in stress space of the bounding and phase transformation lines; (c) principal stress rotation angle; and (d) intermediate stress ratio accounting for stress-induced anisotropy. The calibration procedure is step-by-step validated against experimental data for various drained and undrained loading paths (including triaxial compression and extension, plane-strain compression and direct simple shear) and initial states (relative density and pressure). Three different types of sand are examined to account for diverse behaviour, even for the same initial states and applied stress paths, due to intrinsic anisotropy attributed to fabric effects (e.g. grain size, shape and packing).

Influência da utilização de procedimentos não padronizados de ensaio para a determinação experimental da resistência à compressão simples e do módulo estático de elasticidade do cimento Portland

A resistência à compressão é um dos parâmetros fundamentais usados para controle e caracterização do cimento. O ensaio padrão para determinação da resistência à compressão simples do cimento Portland, normatizado pela NBR 7215 (1), especifica o uso de areia com granulometria determinada e estabelece procedimentos de mistura rigorosos na preparação dos corpos de prova. Sabe-se que, nem sempre, os procedimentos padrão são rigorosamente seguidos, seja devido a fatores relacionados com competência técnica ou pela simplificação da norma, entre outros fatores. O objetivo principal deste trabalho foi avaliar a influência de determinadas simplificações dos procedimentos padrão de ensaio na determinação experimental da resistência à compressão simples do cimento Portland. Foram testados diferentes procedimentos de mistura e utilizados diferentes tipos de agregado miúdo, especificamente, areia média comum ou com granulometria controlada, tomando como referência a denominada areia do Tietê. Foram utilizadas duas amostras de cimento CPV-ARI, provenientes de fabricantes distintos. Para todas as combinações foram realizados ensaios de resistência à compressão e módulo estático de elasticidade nas idades de 1, 3, 7 e 28 dias. Foi efetuada uma análise de variância (ANOVA) para avaliar se as variáveis estudadas geravam diferenças estatisticamente significativas nos resultados experimentais. Foi possível concluir que, de forma geral, a moldagem simplificada não influenciou significativamente a resistência à compressão simples nem o módulo estático de elasticidade do cimento Portland. Por outro lado, o tipo de agregado miúdo utilizado influenciou significativamente a resistência à compressão, mas não impactou o módulo de elasticidade das amostras.

Modelling of Non-linear Shear Displacement Behaviour of Soil–Geotextile Interface

Behaviour of reinforced soil structures depends on the material properties of soil and geosynthetics. Apart from individual properties of soil and reinforcement, the interaction between reinforcement and soil also plays important role in deciding the behaviour of reinforced soil structures. The modelling of the interface characteristics is a very important aspect in developing a correct numerical model for predicting the performance of reinforced soil structures. For simulating the interface behaviour a linearly elastic model with Mohr–Coulomb criterion is commonly used. Experimental observations made from direct shear tests usually show that the force–displacement relationship is non-linear till a peak is attained, beyond which softening behaviour is observed. In this paper a constitutive model appropriate for geosynthetic interfaces has been implemented in FLAC3D and used to simulate the shear stress displacement behaviour of different sand–geotextile interfaces. In the present study, shear stress–displacement behaviour of interfaces of different types of sands and geotextiles (monofilament woven, multifilament woven and nonwoven) have been considered for simulation. The simulated curves using the FLAC3D showed very good agreement with the experimental data over the complete stress-displacement ranges.

Erosion–corrosion behavior and corrosion resistance of AISI 316 stainless steel in flow jet impingement

The purpose of this investigation was to document and understand the tribo-corrosive wear of AISI 316 (UNS S31600) stainless steel under high-speed jet impingement by a sand–liquid, two-phase flow. Wear was determined by weight-loss, the surfaces were characterized, and electrochemical measurements were also performed. Two different types of sands, silica sand and sea sand, were used in the experiments to investigate the effects of working time and chloride ions (from the sea sand). The cumulative weight-losses of the specimens increase with time. Upon the effect of particle size on weight-loss, it is found that the weight loss caused by the smallest particles, over a three hour time increment, decreases more slowly than that from other-sized particles. In addition, the weight-losses of the specimens increase with decreasing impact angle. Erosion from flowing sea sand caused more weight-loss than from flowing silica sand. From electrochemical measurements, the specimen impinged at a moderate angle (60°) shows the best corrosion resistance. The specimens subjected to flowing sea sand had worse corrosion resistance than those subjected to flowing silica sand. The specimen impinged by short time represents a passivation process on the anodic polarization behavior, but the passivation disappears on the specimen impinged by long time.

A Modified Philip–Dunne Infiltrometer for Measuring the Field‐Saturated Hydraulic Conductivity of Surface Soil

There is a current and expanding need to measure surface infiltration rate parameters for stormwater infiltration practices used to mitigate the detrimental effects of land development activities on watershed hydrology. We have developed a falling‐head soil surface infiltrometer, termed the modified Philip–Dunne (MPD) infiltrometer, that is inexpensive to construct, easy to use, and requires a minimal water volume per test. Because of these characteristics, many MPD devices can be deployed simultaneously to obtain infiltration rate data at multiple locations within a given infiltration practice. Green–Ampt theory was used to derive the expressions needed for analyzing the falling‐head data to solve for the field‐saturated hydraulic conductivity (Kfs) and Green–Ampt wetting‐front suction (ψ). The accuracy of the analysis was determined using numerical experiments in which falling‐head data were generated from a computational solution of the axisymmetric form of the three‐dimensional Richards' equation for homogeneous and isotropic porous media with specified input parameters. The falling‐head data were then analyzed using a quasi‐analytical procedure, and the resulting values of Kfs and ψ were compared with the input values. The accuracy of Kfs and ψ derived from data acquired using the MPD device was then assessed using physical experiments involving three large barrels packed with different types of sand. The Kfs values obtained for the media in the barrels using an MPD infiltrometer were, on average, 82% of the values obtained from whole barrel falling‐head tests. The resulting uncertainty in Kfs values from the MPD infiltrometer is considered to be small compared with the orders of magnitude of variability commonly observed for Kfs values in the field.

Exploration Results of Applying Limestone Powder in Crushed-Stone-Sand Mixtures for Road Pavement Layers

This paper presents results of exploration related to C2 and C6 crushed-stone-and-sand ready mixtures strengthened with limestone powder used in road pavement layers. Limestone powder is an industrial waste, which in Ararat region is in big volumes. The samples were taken composed of different fractions of crushed-stone and two types of sand produced from crushed basalt and crushed gravel, and were tested. The composition of ready mixtures meets the requirements of corresponding standard on grain size. To these mixtures limestone powder was added of the percentage range 0-30% of the mixture mass. The main purposes of experimental exploration were to determine the influence of different percentages of limestone powder on compression strength of crushed-stone-and-sand ready mixtures and optimal content of powder. The change of the influence grade was studied by applying different types of sands. Three cylindrical samples were made for each percentage of limestone powder according to a standard method. Compressive strengths of samples have been determined. It was concluded, that the applying limestone powder in C2 and C6 ready mixtures contributes to the cohesion of stone grains as well as to obtaining high indicators of compaction in road pavement layers. The received results allow to arrive to a conclusion that applying limestone powder according to the optimal range distinctly increases the strength characteristics of crushed-stone-sand ready mixtures which in tur contributes the effective implementation of the compacting process. Especially the influence grade is considerable in C6 ready mixtures containing a large amount of crushed stone, as well as in mixtures using sands with smaller fineness modulus.