Fiber Concrete for 3-D Additive Technologies

2019 ◽  
Vol 974 ◽  
pp. 367-372 ◽  
Author(s):  
Sergey V. Klyuev ◽  
Andrey V. Shevchenko ◽  
E.S. Shorstova
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Additive Technologies ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Fine Grained ◽  
Fiber Concrete ◽  
Concrete Placement

Fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

scholarly journals FIBER CONCRETE FOR 3-D ADDITIVE TECHNOLOGIES

2020 ◽  
Vol 2 (4) ◽  
pp. 14-20 ◽  
Author(s):  
Sergey Klyuev ◽  
Aleksandr Klyuev ◽  
Elena Shorstova
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Additive Technologies ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Fine Grained ◽  
Fiber Concrete ◽  
Concrete Placement

fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

scholarly journals Dust Particle Size and Statistical Parameters

2021 ◽  
pp. 57-93
Author(s):  
Noor Al-Dousari ◽  
Modi Ahmed ◽  
Ali Al-Dousari ◽  
Musaad Al-Daihani ◽  
Murahib Al-Elaj
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Fine Sand ◽  
Coarse Sand ◽  
Optical Methods ◽  
Size Analysis ◽  
Coarse Silt ◽  
Statistical Parameters ◽  
Fine Silt

AbstractGrain ‘size’ can be specified and measured in several different ways. All methods of grain size determination have blemishes, and the choice of the most appropriate method is governed by the nature of the sample and the use to which the data are placed. Four main methods are currently used for size analysis of sands: (a) sieving; (b) settling tube analysis; (c) electro-optical methods, including Coulter Counter analysis and laser granulometry; and (d) computerized image analysis. The classification of the particle size distribution of Kuwait dust was mapped according to the parameters proposed by Folk And Ward (1957) which were widely used for quantitative comparisons between natural grain size distribution and the lognormal distribution that shows better sorted sediments have lower values of σ1. Maps of the distribution of dust in Kuwait were obtained that included: fine sand (F.S.), Coarse sand (C.S), Medium Sand (M.S), Very Fine Sane (V.F.S), Very Coarse Silt (V.C.Silt), Coarse Silt (C.Silt), Medium Silt (M.Silt), Fine Silt (F.Silt), Very Fine Silt (V.F.Silt), in addition to that, the deposition percentage of Clay, Sand, mud (silt plus clay) and silt were provided.

scholarly journals Marine substrate response from the analysis of seismic attributes in CHIRP sub-bottom profiles

2017 ◽  
Vol 65 (3) ◽  
pp. 332-345 ◽  
Author(s):  
Larissa Felicidade Werkhauser Demarco ◽  
Antonio Henrique da Fontoura Klein ◽  
Jorge Antonio Guimarães de Souza
Keyword(s):  
Grain Size ◽  
Seismic Reflection ◽  
Ground Truth ◽  
Fine Sand ◽  
Seismic Attributes ◽  
Coarse Sand ◽  
Unconsolidated Sediments ◽  
Shallow Gas ◽  
Size Classes ◽  
Seismic Reflection Profiles

Abstract This paper presents an evaluation of the response of seismic reflection attributes in different types of marine substrate (rock, shallow gas, sediments) using seafloor samples for ground-truth statistical comparisons. The data analyzed include seismic reflection profiles collected using two CHIRP subbottom profilers (Edgetech Model 3100 SB-216S), with frequency ranging between 2 and 16 kHz, and a number (38) of sediment samples collected from the seafloor. The statistical method used to discriminate between different substratum responses was the non-parametric Kruskal-Wallis analysis, carried out in two steps: 1) comparison of Seismic Attributes between different marine substrates (unconsolidated sediments, rock and shallow gas); 2) comparison of Seismic Attributes between different sediment classes in seafloors characterized by unconsolidated sediments (subdivided according to sorting). These analyses suggest that amplitude-related attributes were effective in discriminating between sediment and gassy/rocky substratum, but did not differentiate between rocks and shallow gas. On the other hand, the Instantaneous Frequency attribute was effective in differentiating sediments, rocks and shallow gas, with sediment showing higher frequency range, rock an intermediate range, and shallow gas the lowest response. Regarding grain-size classes and sorting, statistical analysis discriminated between two distinct groups of samples, the SVFS (silt and very fine sand) and the SFMC (fine, medium and coarse sand) groups. Using a Spearman coefficient, it was found that the Instantaneous Amplitude was more efficient in distinguishing between the two groups. None of the attributes was able to distinguish between the closest grain size classes such as those of silt and very fine sand.

scholarly journals Relationship between Grain Size Distribution and Radon Content in Surficial Sediments of Wadi Arar, Saudi Arabia

2018 ◽  
Vol 8 (1) ◽  
pp. 2447-2451 ◽  
Author(s):  
M. A. M. Alghamdi
Keyword(s):  
Grain Size ◽  
Saudi Arabia ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Fine Sand ◽  
Coarse Sand ◽  
Negative Slope ◽  
Surficial Sediments ◽  
Fourth Degree ◽  
Radon Content

Surficial sediments with low radon content are desirable materials in construction applications. In this study, the relationship between grain size and radon content was investigated in sediments collected from seven sites in Wadi Arar, Saudi Arabia, with the intent of determining whether grain size analysis could be used for rapidly assessing the suitability of potential construction materials. Thirty-five samples were collected (five per site) and the grain size distribution was determined using sieves. Radon contents were measured on composite samples with a RAD7 radon detector. Among the sediment types (gravel, coarse sand, medium sand, fine sand, and silt and clay), the best linear correlations between grain size and radon contents were found for the coarse sand (negative slope, r=0.82) and fine sand (positive slope, r=0.78). Polynomial relationships were also tested. A fourth-degree polynomial equation effectively described the correlation between grain size and radon content (R2 = 0.933). As shown by this model, the highest correlations with radon contents were detected at grain sizes smaller than 2.0 mm. Thus, grain size may be useful for preliminary site assessment work.

scholarly journals Universal relation with regime transition for sediment transport in fine-grained rivers

2019 ◽  
Vol 117 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Hongbo Ma ◽  
Jeffrey A. Nittrouer ◽  
Baosheng Wu ◽  
Michael P. Lamb ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sediment Load ◽  
Yellow River ◽  
Fine Sand ◽  
Sediment Flux ◽  
Universal Relation ◽  
Sediment Grain Size ◽  
Fine Grained ◽  
Predictive Algorithm ◽  
Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

scholarly journals Anisotropic Shear Strength Behavior of Soil–Geogrid Interfaces

2021 ◽  
Vol 11 (23) ◽  
pp. 11387
Author(s):  
Jun Zhang ◽  
Mingchang Ji ◽  
Yafei Jia ◽  
Chenxi Miao ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Great Influence ◽  
Fine Sand ◽  
Coarse Sand ◽  
Shear Direction ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Strength Behavior ◽  
Sand And Gravel

This paper presents an experimental study on the anisotropic shear strength behavior of soil–geogrid interfaces. A new type of interface shear test device was developed, and a series of soil–geogrid interface shear tests were conducted for three different biaxial geogrids and three different triaxial geogrids under the shear directions of 0°, 45° and 90°. Clean fine sand, coarse sand, and gravel were selected as the testing materials to investigate the influence of particle size. The experimental results for the interface shear strength behavior, and the influences of shear direction and particle size are presented and discussed. The results indicate that the interface shear strength under the same normal stress varies with shear direction for all the biaxial and triaxial geogrids investigated, which shows anisotropic shear strength behavior of soil–geogrid interfaces. The soil–biaxial geogrid interfaces show stronger anisotropy than that of the soil–triaxial geogrid interfaces under different shear directions. Particle size has a great influence on the anisotropy shear strength behavior of soil–geogrid interfaces.

scholarly journals Particle Size Imbalance Index from Compositional Analysis to Evaluate Cereal Sustainability for Arid Soils in Eastern Algeria

Agriculture ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 296
Author(s):  
Siham Zaaboubi ◽  
Lotfi Khiari ◽  
Salah Abdesselam ◽  
Jacques Gallichand ◽  
Fassil Kebede ◽  
...  
Keyword(s):  
Particle Size ◽  
Management Practices ◽  
Compositional Analysis ◽  
Fine Sand ◽  
Particle Size Analysis ◽  
Coarse Sand ◽  
Richards Equation ◽  
Size Analysis ◽  
Fine Silt ◽  
Eastern Algeria

For homogeneous fertilization and crop management practices, this work hypothesized that texture could influence cereal yield, particularly in dry regions. Particle size analysis could help improve knowledge of the soil-plant relationship to obtain favorable conditions for better yield. The objective of this work is to develop a single granulometric index for durum wheat (Triticum durum) that is well correlated with yield. For this purpose, 350 independent samples of cereal soils from eastern Algeria were taken and the recorded yields were linked to these samples. The cutoff yield, which separates sub-populations with acceptable yield from those with less acceptable yield, was determined from the inflection point of the cumulative variance ratio functions related to yield by the Richards’ equation. The result obtained is 2.0 Mg.ha−1, with a theoretical critical chi-square value of 4.2, close to 4.6, which is the critical value of r2granulo as obtained by the Cate-Nelson procedure. The five-granulometric indices were found to be symmetrical around zero as follows: ±0.83 for clay (IC), ±1.73 for fine silt (IFL), ±0.31 for coarse silt (ICL), ±0.44 for fine sand (IFS), and ±1.30 for coarse sand (ICS). The two fractions that most influence the textural imbalance are fine silt (IFL) and coarse sand (ICS), with a contribution of 41% and 37%, respectively. The critical single imbalance index r g r a n u l o 2 can be used for determining cereal suitability for soils in the arid region of eastern Algeria. The lower the   r g r a n u l o 2 is, the better the soil for cereal crops.

CARACTERIZAÇÃO DOS ASPECTOS SEDIMENTOLÓGICOS E GRANULOMÉTRICOS ASSOCIADOS À FOZ DO RIO COREAÚ – CE, BRASIL

2019 ◽  
Vol 21 (2) ◽  
pp. 265-278
Author(s):  
Tarcyana Câmara Barroso ◽  
Paulo Roberto Silva Pessoa ◽  
Antônio Rodrigues Ximenes Neto ◽  
Jáder Onofre de Morais
Keyword(s):  
Grain Size ◽  
River Mouth ◽  
Fine Sand ◽  
Fine Grained ◽  
Quartz Sands ◽  
Geomorphological Units ◽  
Marine Influence ◽  
Del Rio ◽  
Atmospheric Systems ◽  
Fine Gravel

A zona costeira é um ambiente dinâmico de transição que apresenta uma interface entre os sistemas continentais, marinhos e atmosféricos. A área de estudo se localiza no município de Camocim-CE na região da foz do rio Coreaú, compreendendo também áreas adjacentes em ambas às margens. O objetivo deste trabalho foi analisar os aspectos deposicionais a partir da granulometria dos sistemas ambientais costeiros, para caracterização sedimentológica das principais unidades geomorfológicas da foz do rio Coreaú. Em campo foram coletadas amostras superficiais de três sistemas litorâneos – Duna; Estirâncio e Estuário. A sedimentação da área estudada é controlada pela influência marinha, com a predominância de areias quartzosas muito fina no subsistema duna e estuário. No estirâncio defronte a falésia costeira na margem esquerda houve predominância de cascalho fino. Já o estirâncio da Ilha do amor apresentou areia grossa e muito fina no estirâncio superior e inferior, respectivamente.Palavras-chave: Rio Coreaú; Sedimentologia; Granulometria. ABSTRACTThe coastal zone is a dynamic transition between the continental, marine, and atmospheric systems. The study area is located in the Coreaú river mouth, Camocim-CE. The aim was to characterize the depositional aspects from the grain size and sedimentology of coastal environmental systems to characterize the main geomorphological units. It was collected superficial samples of three coastal systems - Dune; Foreshore and Estuary. The sedimentation is controlled by the marine influence, with the predominance of very fine-grained quartz sands in the dune and estuary. In the foreshore of the coastal cliff at the left margin there was a predominance of fine gravel, as well as coarse and very fine sand in the upper and lower foreshore, respectively (Ilha do Amor).Keywords: Coreaú River; Sedimentology; Grain Size. RESUMEN La zona costera es un entorno dinámico de transición que presenta una interfaz entre los sistemas continentales, marinos y atmosféricos. La zona de investigación está ubicada en la ciudad de Camocim-CE, en la desembocadura del río Coreaú, y además comprende zonas adyacentes en ambas márgenes. El objetivo de la investigación fue caracterizar los aspectos deposicionales desde la granulometría de los sistemas ambientales costeros presentes en la zona, para caracterización sedimentario de las principales unidades geomorfológicas de la desembocadura del río Coreaú. La continuación se recogieron muestras superficiales de tres sistemas litorales – Duna; estrán y estuario. La sedimentación del área está controlada por la influencia marina, con la predominancia de arenas cuarzo muy fina en el subsistema duna y estuario. En la zona intermareale frente al acantilado costero en la margen izquierda hubo predominancia de arena fina. Ya en la zona intermareale de la Ilha do Amor presentó arena gruesa y muy fina en la estrán superior e inferior, respectivamente.Palabras clave: Río Coreaú; sedimentología; granulometría.

scholarly journals Major Characteristics of Surface Sediments Within the Shallow Water of the Cat Ba Island, North Vietnam

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Nguyen Huy Hoang ◽  
Bui Van Vuong ◽  
Evgenii Egidarev ◽  
Vasiliy Zharikov ◽  
Le Anh Xuan ◽  
...  
Keyword(s):  
Mineral Composition ◽  
Surface Sediments ◽  
Ph Value ◽  
Fine Sand ◽  
Coarse Sand ◽  
Coarse Silt ◽  
Terrigenous Sediment ◽  
Fine Grained ◽  
Reducing Environment ◽  
North Vietnam

The Cat Ba is one of the largest Islands offshore North Vietnam, which is characterized by an abundance of coral reefs in the East and Southeast of the island. The surface sediments are considered the basic elements for the coral ecosystem development. In this study, the authors present some new results studying pH, Eh, mineral composition, and grain size as the basic information for environmental assessment of this area. The results show that the pH value of the surface sediment varies from 6.90 to 8.09, with an average of 7.24 while the Eh value of the sediment ranges from -121.10 to -48.20mV,  an average of -68.39mV, demonstrating a reducing environment. The surface sediments have been classified into 8 size classes: the coarse silt > very coarse silt > medium sand, very fine sand > very coarse sand, fine sand > coarse sand, very fine gravel. Most of the sediments are poorly sorted - very poorly sorted, only a few sedimentary samples are well sorted, moderately sorted, and moderately well sorted. The average mineral composition of the surface sediments consists of: 25% quartz, 17% illite, 16% aragonite, 13% kaolinite, 10% calcite, 5% chlorite, 4% gothite, 3% halite, 2% feldspar and less montmorillonite, and dolomite. These results allowed the researcher to interpret that the sediments have been deposited in a relatively calm environment and the terrigenous sediment sources are dominant over the marine sources. Source marine sediment groups are characterized by coarse grains, high pH, and are rich in carbonate minerals, which have been produced by biological materials. In contrast, the terrigenous sediment group is dominated by fine-grained sediments, rich clay minerals, quartz, and gothite. These fine-grained sediments are commonly distributed in the area and are favorable places for pollutant accumulation.  

scholarly journals PROBABILITY OF PARTICLE-SIZE FRACTIONS OCCURRENCE IN DIFFERENT LANDFORMS

2018 ◽  
Vol 26 (4) ◽  
pp. 352-359
Author(s):  
Julião Soares de Souza Lima ◽  
Samuel Assis Silva ◽  
Daniel Pena Pereira ◽  
Marcelo Soares Altoé
Keyword(s):  
Particle Size ◽  
Clay Fraction ◽  
Spherical Model ◽  
Fine Sand ◽  
Coarse Sand ◽  
Indicator Kriging ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Probability Of Occurrence ◽  
Present Pattern

Knowing the variation of particle-size fractions, considering the relief forms, contributes for understanding the variation of other soil attributes. This work aimed to study the spatial distribution of the probability of particle-size fractions occurrence (clay, silt, very fine sand, fine sand, coarse sand, and total sand) in a clayey Oxisol with predominance of concave and convex curvatures. A sampling grid with 94 sampling points in 33x33m spacing at a depth of 0–0.20 m was built using a GPS. The spatial analysis was performed through indicator kriging. The spherical model was fit for all soil fractions, with ranges varying from 130 m to 280 m. In the region of convex curvature, the clay fraction presented the highest probability of occurrence (0.75 to 1.00), whereas in the concave region the coarse sand and total sand fractions presented the highest probability of occurrence. The very fine sand fraction and the silt did not present pattern of distribution in relation to the dominant curvatures of the relief.

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