scholarly journals Qualitative and quantitative assessment of gravel deposits between Aaptar and Malekhu, Central Nepal for aggregates

2017 ◽  
Vol 18 ◽  
pp. 49-58
Author(s):  
Sunu Dawadi
Keyword(s):  
Los Angeles ◽  
Chemical Weathering ◽  
Physical And Mechanical Properties ◽  
Sodium Sulphate ◽  
Effective Porosity ◽  
Raw Material ◽  
Market Demand ◽  
Sediment Size ◽  
Los Angeles Abrasion

The Malekhu Khola is rich in sediments which are widely exposed along its banks. In recent years, river mining sites have been established and mining has been carried on to produce aggregates to meet a small portion of the market demand. Because the riverbank deposits are of heterogeneous composition, quality of the aggregate from such deposits is of main issue. This study therefore, aims to evaluate quality of river sediment to know its suitability for aggregate as raw material for various uses, and the volume of the deposit. Field observation and intensive laboratory works were carried out to evaluate aggregates. The samples of aggregates were analyzed for texture, composition, durability and physical and mechanical properties. Majority of the aggregate particles were found metamorphic rocks of the Lesser Himalaya like quartzite, schist, marble, metasandstone, amphibolites, gneiss and granite, etc. Most of the deposits were matrix-supported and the matrix was basically sandy. The majority of clasts showed bladed to disc, and were generally rounded to sub rounded. The sediment size ranged from granule to upto boulder but the modal size was of cobble grade. While tested for gradation, the coarse aggregates ranged from uniform to gap graded categories. In terms of shape, workability of aggregate was found satisfactory. Aggregate samples possessed low Water Absorption Value (0.53–1.08%) and thus low effective porosity. Aggregate Impact Value (13.40–15.70%) and Aggregate Crushing Value (17.50–19.67%) showed good soundness. Los Angeles Abrasion Value (37.00–48.40%) showed the consistent hardness of each of the samples. The low range of Sodium Sulphate Soundness Value (1.37–2.16%) indicated good resistance of aggregates against chemical weathering and frosting. The aggregates were also resistant to slaking as indicated by very high range of Slake Durability Strength Index (98.67–99.72%). Comparing with the existing Nepal Standard (NS), British Standard (BS) and American Standard of Testing Material (ASTM), the studied samples were suitable for concrete structures and unbound pavements. Six different localities were considered in the study area to estimate for resource of aggregates. The total volume of the deposits was estimated to be 392273 cubic meter.Bulletin of the Department of Geology, Vol. 18, 2015, pp. 49-58

scholarly journals Evaluation of gravel for concrete and road aggregates, Rapti River, Central Nepal Sub-Himalaya

1970 ◽  
Vol 10 ◽  
pp. 99-106 ◽  
Author(s):  
Surendra Maharjan ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Los Angeles ◽  
Chemical Weathering ◽  
Effective Porosity ◽  
Raw Material ◽  
British Standard Institution ◽  
Dry Density ◽  
Carbonate Group ◽  
British Standard ◽  
Los Angeles Abrasion

Several local mining sites of sand and gravel have been operating for decades in the Rapti River. River gravels are consumed in Hetauda, Narayanghad and areas in India near the border between Nepal and India. Until now little known about consumers concerning about quality of gravel. The present study was carried out to evaluate quality of river gravel to know its suitability for aggregate (raw material for concrete and road). The samples of river gravel were analysed for petrographic, physical, mechanical and chemical properties. Samples were categorised as quartzite group, carbonate group and granite group according to British Standard Institution (BSI). Among these, samples of quartzite group were found dominant. Image analysis of gravel showed that clasts were well graded. The majority of the samples had rounded, high sphericity and oblate triaxial clasts. The surface texture of clasts was rough to smooth. In terms of shape, workability of gravel was satisfactory. Gravel samples possessed low water absorption value (0.69 to 1.12%) and low effective porosity. Dry density of samples ranged from 2460 to 2680 kg/m3. Aggregate impact values of samples (14.2 to 16.1%) showed good soundness. Los Angeles abrasion test also showed consistent hardness of each of the samples as uniformity factor did not exceed 0.2. Magnesium sulphate values ranged between 4.46% and 7.29% suggesting good resistance against chemical weathering and frosting. Comparing with the existing Nepal Standard, British Standard and American Standard of Testing Material, the studied samples were suitable for concrete and road aggregates.   doi: 10.3126/bdg.v10i0.1425      Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 10, 2007, pp. 99-106

scholarly journals EVALUATING THE SAWABILITY OF ROCKS BY CHAIN-SAW MACHINES USING THE PROMETHEE TECHNIQUE

2021 ◽  
Vol 36 (1) ◽  
pp. 25-36
Author(s):  
Reza Mikaeil ◽  
Akbar Esmaeilzadeh ◽  
Sara Aghaei ◽  
Sina Shaffiee Haghshenas ◽  
Amir Jafarpour ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Los Angeles ◽  
Production Rate ◽  
Physical And Mechanical Properties ◽  
Dimension Stone ◽  
Quartz Content ◽  
Los Angeles Abrasion ◽  
Production Values ◽  
Schmidt Hardness ◽  
Dimension Stone Quarry

One of the most significant factors in the estimation of dimension stone quarry cost is the production rate of rock cutting machines. Evaluating the production rate of chain-saw machines is a very significant and practical issue. In this research, it has been attempted to evaluate and select the suitable working-face for a quarry by examining the maximum production rate in the Dehbid and Shayan marble quarries. For this purpose, fi eld studies were carried out which included measuring operational characteristics of the chain-saw cutting machine, the production rate and sampling for laboratory tests from seven active case studies. Subsequently, the physical and mechanical properties of rocks including: Uniaxial Compressive Strength (UCS), Brazilian Tensile Strength (BTS), Los Angeles abrasion, quartz content, water absorption percentage, porosity, Schmidt hardness and grain size for all sample measurements were studied after transferring the samples to a rock-mechanics laboratory. Finally, the sawability of the quarried working-faces was evaluated using the PROMETHEE multi-criteria decision-making (MCDM) model according to the physical and mechanical properties. The results of the study indicated that the number 1 and 5 working-faces from the Dehbid and Shayan quarries are the most suitable working-faces in terms of production rate with the maximum recorded production values (4.95 and 3.1 m2 /h), and with net fl ow rates (2.67 and -0.36) respectively.

Calculation of debarking drum in the Matlab environment.

2016 ◽  
Author(s):  
Л.Д. Бухтояров ◽  
И.В. Григорьев ◽  
О.А. Куницкая ◽  
А.Е. Лукин ◽  
Д.Е. Куницкая
Keyword(s):  
Physical And Mechanical Properties ◽  
Wood Chips ◽  
Raw Material ◽  
Structural Elements ◽  
Wood Processing ◽  
Processing Times ◽  
Basic Parameters ◽  
The Stability ◽  
Probabilistic Nature

Из древесины производится около 20 тысяч наименований продукции, причем около 95% приходится на продукцию химической и механо-химической переработки древесины. Большая часть таких производств в качестве сырья потребляет технологическую щепу, к которой предъявляются требования по наличию в ней коры, гнилей и минеральных включений. Наиболее трудо- и энергоемкой операцией технологического процесса по производству технологической щепы является окорка балансовой древесины, которая в подавляющем большинстве случаев производится методом групповой окорки в окорочных барабанах различной конструкции. В статье представлена математическая модель процесса групповой окорки лесоматериалов в окорочных барабанах, позволяющая оценивать один из основных параметров групповой окорки лесоматериалов – время их обработки, при котором будут минимизированы потери древесины без снижения качества окорки, с учетом конструктивных элементов барабана, параметров балансов, их свойств и температуры. Учтен вероятностный характер таких показателей, как время окорки, физико-механические свойства коры и древесины, особенности распределения слоев коры по глубине, что обусловило необходимость применения математической модели, основанной на принципах ситуационного моделирования процессов перехода лесоматериала из одного состояния в другое. Методика расчета и управления основными параметрами процесса позволяет разрабатывать организационные, технологические и технические мероприятия, обеспечивающие стабильность качественных показателей групповой окорки лесоматериалов в окорочных барабанах. Также модель представлена в виде функциональной блок-схемы, основанной на графическом интерфейсе Matlab с приложением Simulink. Используя наборы блоков Simulink, отвечающих за константы, переменные, функции, и вычислительные операции, организован процесс расчета основных параметров объектно-ориентированным ме­тодом. Wood is produced about 20 thousand kinds of products, with about 95% products of the chemical and mechano-chemical processing of wood. Most of these industries as raw material consumes wood chips, which are requirements for the presence of bark, rot and mineral inclusions. Most labor and energy intensive operation of the technological process for the manufacturing of wood chips is the debarking of pulpwood, which in the vast majority of cases, produced by a group of debarking in debarking drums of various designs. The article presents a mathematical model of the process of group debarking wood in debarking drums allows one to assess one of the key parameter group of debarking wood – processing times, which will be minimized wood losses without reducing the quality of the debarking, taking into account the structural elements of the drum, the balance parameters, their properties and temperature. Account the probabilistic nature of such indicators as: debarking, physical and mechanical properties of bark and wood, the distribution of layers of crust at depth, which necessitated the use of mathematical models based on the principles of situational simulation of the transition branch from one state to another. Calculation method and basic parameters of the process allows us to develop organizational, technological and technical measures ensuring the stability of quality indicators of group debarking wood in debarking drums. Also, the model presented in the form of functional block diagrams based on the graphical user interface of Matlab with Simulink application. Using the Simulink block sets of charge constants, variables, functions, and compute the organized process of calculating the basic parameters of the object-oriented method.

scholarly journals Optimal Manufacturing-Remanufacturing Production Policy for a Closed-Loop Supply Chain under Fill Rate and Budget Constraint in Bifuzzy Environments

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Soumita Kundu ◽  
Tripti Chakrabarti ◽  
Dipak Kumar Jana
Keyword(s):  
Supply Chain ◽  
Closed Loop ◽  
Budget Constraint ◽  
Raw Material ◽  
Market Demand ◽  
Fill Rate ◽  
Closed Loop Supply Chain ◽  
Manufacturing Facility ◽  
Production Policy

We study a closed-loop supply chain involving a manufacturing facility and a remanufacturing facility. The manufacturer satisfies stochastic market demand by remanufacturing the used product into “as-new” one and producing new products from raw material in the remanufacturing facility and the manufacturing facility, respectively. The remanufacturing cost depends on the quality of used product. The problem is maximizing the manufacturer’s expected profit by jointly determining the collected quantity of used product and the ordered quantity of raw material. Following that we analyze the model with a fill rate constraint and a budget constraint separately and then with both the constraints. Next, to handle the imprecise nature of some parameters of the model, we develop the model with both constraints in bifuzzy environment. Finally numerical examples are presented to illustrate the models. The sensitivity analysis is also conducted to generate managerial insight.

Comparative Evaluation of Dolerite and Syenite as Crushed Stone Aggregate

2013 ◽  
Vol 824 ◽  
pp. 73-78
Author(s):  
E.O. Eze ◽  
O.U. Orie
Keyword(s):  
Compressive Strength ◽  
Los Angeles ◽  
Specific Gravity ◽  
Moisture Absorption ◽  
Ultrasound Velocity ◽  
Sodium Sulphate ◽  
Point Load ◽  
Crushed Stone ◽  
Point Load Index ◽  
Los Angeles Abrasion

Dolerite and syenite were comparatively studied and evaluated for their potential as crushed stone for civil engineering construction. Properties of the rocks tested included specific gravity, moisture absorption, Schmidt hammer rebound, point-load strength, unconfined compressive strength, Los Angeles abrasion, aggregate crushing value, sodium sulphate soundness, and ultrasound velocity. The thermal heat capacity and coefficient of expansion of the stones were also determined. The rocks had high specific gravity of over 2.75, high compressive strength of 196-256 MPa, high point load index (Is50) of 17-23 MPa and low porosity of 0.27-0.29 % required of good aggregates. However, the rather high moisture absorption and high magnesium sulphate loss of the rocks exceeded the 3 and 18 % considered as the upper limits for good aggregates. This raised concern as to the durability of the rocks under aggressive environment. Also, the ferromagnesian minerals of the dolerite are prone to deteriorate badly under harsh environment. The typically elongate and angular aggregate shape of dolerite aggregate meant poor mix workability and more cement requirement for a given strength than the less angular syenite aggregate.

scholarly journals Quality of Pinus sp. pellets with kraft lignin and starch addition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paula Gabriella Surdi de Castro ◽  
Humberto Fauller de Siqueira ◽  
Vinícius Resende de Castro ◽  
Antônio José Vinha Zanuncio ◽  
José Cola Zanuncio ◽  
...  
Keyword(s):  
Corn Starch ◽  
Physical And Mechanical Properties ◽  
High Energy ◽  
Kraft Lignin ◽  
Raw Material ◽  
High Energy Density ◽  
Wood Pellets ◽  
Structural Fragility ◽  
Renewable Raw Material

AbstractPellets are widely used for power generation because they use renewable raw material with easy storage, transport and high energy density. However, the structural fragility, disintegrating during handling, transport and storage, is one of the main problems of pellets, but the addition of binders/additives can minimize this fragility. The objective of this study was to evaluate the properties of wood pellets with the addition of starch (corn and wheat) and kraft lignin in different proportions. Pellets were produced with the addition of starch (wheat and corn) and kraft lignin in the proportions of 1, 2, 3, 4 and 5% in relation to the mass of wood particles of Pinus sp., with 12% moisture (dry basis), classified in 3 and 1 mm sieves and compacted in a pelleting press in the laboratory, according to European standard EN 14961-2. Physical and mechanical properties of the pellets were evaluated and their densitometric profiles obtained from the Faxitron LX-60 X-ray equipment. Corn starch and kraft lignin additives at 4% improved pellet properties (density, fines and hardness), reducing their losses during handling, storage and transport.

scholarly journals PENGARUH PENAMBAHAN PASIR PADA ENDAPAN LUMPUR DANAU LIMBOTO SEBAGAI PEMBUATAN BATU BATA

2018 ◽  
Vol 1 (2) ◽  
pp. 8
Author(s):  
Ilyas Ichsan
Keyword(s):  
Mechanical Properties ◽  
Quantitative Research ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Sand Mixture ◽  
The Right ◽  
Lake Sludge

Research on the use of limboto lake sludge as raw material for bricks by adding sand as a mixture of materials using experimental quantitative research. In the study used limboto lake silt with sand mixture with variations of2%, 5%, 7%, 10% and 15%. Related variables are physical and mechanical properties of bricks. The controlling variable is the materials used.The results showed that bricks with raw material from limboto lake sludge with a mixture of sand with variations of 2%,5%, 7%, 10% and 15% did not produce the right composition to have the same quality of bricks with bricks using raw materials clay. Penelitian pemanfaatan endapan lumpur danau limboto sebagai bahan baku batu bata dengan penambahan pasir sebagai bahan campurnya menggunakan penalitian kuantitatif yang bersifat eksperimen. Dalam penelitian digunakan bahan endapan lumpur danau limboto dengan campuran pasir dengan variasi 2%, 5%, 7%, 10% dan 15%. Variabel terkait berupa sifat fisik dan mekanik batu  bata. Variabel pengendali adalah bahan-bahan yang digunakan. Hasil penelitian menunjukan bahwa batu bata dengan bahan baku endapan lumpur danau limboto dengan campuran pasir dengan variasi 2%, 5%, 7% 10% dan 15% tidak  menghasilkan komposisi yang tepat untuk memiliki kualitas batu bata yang sama dengan batu bata yang menggunakan bahan baku tanah liat.

SIFAT FISIS DAN MEKANIS ANYAMAN BAMBAN (Donax canniformis) DENGAN BAHAN STABILISATOR PEG 1000 DAN TANIN KULIT AKASIA

2014 ◽  
Vol 7 (2) ◽  
pp. 23
Author(s):  
Dwi Harsono
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Biological Resources

Bamban (Donax canniformis) is one of the biological resources that grow in the swampy areas and has been used by the community as a raw material in the form of woven handicrafts. Bamban bark that used as raw material woven texture is hard and the surface was very slippery so hard to make. This study was conducted to determine the nature of the characteristics of stem Bamban and determine the effectiveness of the stabilizers PEG 1000 and tannin from extract acacia bark in improving the quality of physical and mechanical properties strands of Bamban. Treatments include immersion with PEG 1000 and acacia bark tannins for 2 hours. Results of the study the effectiveness of treatments of soaking the material stabilizers PEG 1000 and tannins from extract acacia bark all of them can improve the physical and mechanical properties of raw material of Bamban woven handicraft and make it easier for artisans in the process of weaving due to the treated material can make more limp strands of Bamban and not to stiff, in addition to making the product brighter and more attractive.Keywords : bamban, physical properties , mechanical  properties

scholarly journals Some Properties of Eastern Red Cedar (Juniperus Virginiana L.) Particleboard Panels Made Using Modified Starch as Binder

2020 ◽  
Vol 71 (4) ◽  
pp. 371-377
Author(s):  
Onur Ulker ◽  
Salim Hiziroglu
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Juniperus Virginiana ◽  
Modified Starch ◽  
Thickness Swelling ◽  
Eastern Red Cedar ◽  
Red Cedar

The objective of this study was to evaluate physical and mechanical properties of experimental panels manufactured from eastern red cedar (Juniperus virginiana L.) using modified starch as binder. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB), hardness and dimensional stability in the form of thickness swelling and water absorption in addition to surface quality of the samples were tested. Panels were manufactured at three density levels, which are 0.60 g/cm3, 0.70 g/cm3 and 0.80 g/cm3. The highest MOE, MOR and IB values for the samples having 0.80 g/cm3 density were determined as 2207.16 MPa, 15.17 MPa and 0.87 MPa, respectively. Thickness swelling values of the samples soaked in water for 2 h ranged from 15.38 % to 23.23 %. Micrographs taken on the samples using scanning electron microscope revealed that starch was uniformly distributed within the particles. Based on the findings in this study, it appears that eastern red cedar would have a potential as a raw material to manufacture particleboard panel using modifi ed starch as green adhesive with accepted physical and mechanical properties.

scholarly journals PREDICTION OF LIFESPAN OF RAILWAY BALLAST AGGREGATE ACCORDING TO MECHANICAL PROPERTIES OF IT

2017 ◽  
Vol 12 (3) ◽  
pp. 203-209 ◽  
Author(s):  
Vaidas Ramūnas ◽  
Audrius Vaitkus ◽  
Alfredas Laurinavičius ◽  
Donatas Čygas ◽  
Aurimas Šiukščius
Keyword(s):  
Mechanical Properties ◽  
Los Angeles ◽  
Static Loading ◽  
Main Criterion ◽  
Railway Ballast ◽  
Los Angeles Abrasion ◽  
Structure Assessment ◽  
The Relationship ◽  
Selection Of

As the railway lifespan is the main criterion for selection of the aggregate for ballast and for planning the maintenance of the railroad, it is important to define the relationship between the particle load resistant characteristics and a lifetime of ballast in structure. Assessment of the quality of the ballast aggregate particles under dynamic and static loading reflect both, the toughness and hardness, and these are identified with the Los Angeles Abrasion and Micro-Deval Abrasion values. The model formerly developed by Canadian Pacific Railroads was adapted to predict possible loads expressed in cumulated tonnes. Different ballast aggregate mixtures were tested in the laboratory including dolomite and granite. Calculated potential gross tonnage (expressed in Million Gross Tonnes) of the railway per lifetime for each different aggregate type presented. The outcome of this research is established classification system of railway ballast aggregate and defined Los Angeles Abrasion and Micro-Deval Abrasion values of aggregate dependently on required lifetime.

Sign in / Sign up

Export Citation Format

Share Document