Name: choosing well-graded sand for concrete
Uploaded: 2024-11-07T14:48:54.000Z
Duration: 1 min 24 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Biology

BIO.2

BIO.2.D

Design Example: Aggregate Gradation

يحتاج مدير مصنع الخرسانة إلى الاختيار بين منشأتين لإنتاج الرمل المصنع، A و B، لشراء الرمل الذي يلبي التدرج المطلوب للاستخدام في الخرسانة.
يتم جمع عينات من الرمل المصنع من السيور الناقلة في كلا المنشأتين بعد إيقاف الأحزمة.
يتم تباعد قالبين وإدراجهما في تيار الرمال.
يتم نقل المواد الكاملة في الفراغ بين القالب إلى حاوية.
يتكرر هذا في موقعين عشوائيين آخرين على الحزام.
ثم يتم خلط العينات التي تم جمعها لتشكيل عينة تمثيلية ، ووضع علامات عليها ، وحفظها في فرن حتى تجف.
يتم تقسيم العينات المجففة باستخدام مقسم الرمل إلى أجزاء متساوية ، والتي تخضع بعد ذلك لتحليل الغربال عن طريق المرور عبر مجموعة من المناخل القياسية.
يتم رسم منحنى التدرج المقابل.
ويلاحظ أن منحنى التدرج للرمل من المنشأة A يقع ضمن المنطقة المربوطة بالحدود المحددة وفقا لتصميم الخلطة الخرسانية.
وعلى النقيض من ذلك، فإن الرمال من المرفق B تقع خارج هذه المنطقة. نتيجة لذلك ، يقرر المدير شراء الرمل المصنع في المنشأة أ.

مثال على التصميم: تدرج الجسيمات

<div dir="rtl">
إن اختيار النوع والجودة المناسبين من الجسيمات أمر بالغ الأهمية للخرسانة لأنها تؤثر بشكل كبير على خصائصها ونسب الخلط والفعالية من حيث التكلفة. إذا كانت هناك مصادر مختلفة للرمل، فأن الجسيمات الدقيقة هى الاكثراستخداماً في الخرسانة، ويعتمد اختيار الرمل في المقام الأول على تدرجه.
يتم تحديد تصنيف الرمل أو توزيع حجم الجسيمات باستخدام تحليل المنخل، حيث تتراوح الأحجام القياسية من 150 ميكرومتر إلى 10 مم ( ASTM رقم 100منخل إلى 9.52 مليمتر منخل ). يتم أخذ عينات من الرمل لتصنيفها من تيار متدفق من الكتل أو أحزمة ناقلة أو أكوام. تمثل العينة الواحدة عادة حوالي 45000 إلى 50000 كيلوجرام من الرمل. أخيرًا، يتم الحصول على أجزاء الاختبار لتحليل المنخل من العينة الميدانية باستخدام مقسم العينة.
إن الخرسانة التي تستخدم رمالاً ناعمة للغاية قد تكون غير اقتصادية، كما أن الرمال الخشنة قد تؤدي إلى خلطات أقل قابلية للعمل. وبشكل عام، يفضل استخدام رمل جيد التدرج في الخرسانة، دون نقص أو زيادة كبيرة من أي حجم، وإعطاء منحنى تدرج سلس ضمن المنطقة التي يحدها منحنى التدرج للرمل الناعم والخشن.
</div>

يحتاج مدير مصنع الخرسانة إلى الاختيار بين منشأتين لإنتاج الرمل المصنع، A و B، لشراء الرمل الذي يلبي المتطلبات ...

Education

JoVE Core

Civil Engineering

الهندسة المدنية

Unit 1

الوحدة الأولى

Design Examples

أمثلة على التصميم

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

choosing well-graded sand for concrete

Well-graded sand is important in concrete because aggregate choice affects strength, mix proportions, and cost. In concrete, sand is the common fine aggregate. When more than one sand source is available, its gradation often guides the selection.

Gradation means the particle-size distribution of the sand. Engineers measure it with sieve analysis, which uses standard sieve sizes from 150 μm to 10 mm, from ASTM No. 100 to the 3/8 in. sieve. This test shows how much sand stays on each sieve and helps compare one source with another.

Sand for gradation testing can be taken from a flowing aggregate stream, conveyor belts, or stockpiles. A single field sample usually represents about 45 to 50 tons of sand. The test portions for sieve analysis are then taken from that field sample with a sample splitter.

Both very fine and very coarse sands can cause problems in concrete. Very fine sands can make the mix uneconomical. Coarse sands can reduce workability, which makes the concrete harder to place and finish.

For this reason, well-graded sand is preferred. It has no major lack or excess of any size and gives a smooth grading curve between the limits for fine and coarse sand. This balance helps concrete perform better and keeps the mix practical to use.

Choosing Well-Graded Sand for Concrete

design example: dimensioning of concrete masonry construction

design-example-dimensioning-of-concrete-masonry-construction

Sizing a Storeroom with Masonry Blocks

Sizing a storeroom with concrete masonry blocks starts with matching the wall plan to the actual block size and mortar joints. The site has concrete masonry units with a nominal size of 8 by 8 by 16 inches. The storeroom is planned with external dimensions of 12 feet long and 8 feet wide. The wall layout uses nine blocks along the length and six blocks along the width. Each block is actually 7 and 5/8 inches high and wide, and 15 and 5/8 inches long. A 3/8 inch mortar joint is included, so the...

design example: joints in concrete pavements

design-example-joints-in-concrete-pavements

Concrete Pavement Joint Types and Functions

Concrete pavement joints guide where slabs crack and help protect the pavement over time. They support the structural integrity and long life of the concrete by controlling movement and cracking. Contraction joints, also called control joints, are made by sawing a groove into the concrete soon after it hardens. This groove creates a weakened vertical plane. It encourages cracking at a planned location instead of letting cracks form randomly across the slab. Isolation joints are used where the...

design example: aggregate gradation

Well-graded sand is important in concrete because aggregate choice affects strength, mix proportions, and cost. In concrete, sand is the common fine aggregate. When more than one sand source is available, its gradation often guides the selection. Gradation means the particle-size distribution of the sand. Engineers measure it with sieve analysis, which uses standard sieve sizes from 150 μm to 10 mm, from ASTM No. 100 to the 3/8 in. sieve. This test shows how much sand stays on each sieve and...

design example: managing concrete workability

design-example-managing-concrete-workability

Concrete Slump Test in Hot Weather

Concrete slump testing helps track workability during a raft foundation pour in hot weather. Workability means fresh concrete is easy to place, compact, and finish. In this example, the concrete had to be prepared for a large foundation, so keeping it workable was important for quality and durability. The first slump test showed low workability. The mix was losing water quickly, and the high temperature made the coarse aggregates hotter as well. To reduce that effect, the site engineer cooled...

design example: distributing reinforcements in concrete sections

design-example-distributing-reinforcements-in-concrete-sections

Sizing Steel Bars for a Concrete Beam

Sizing steel bars for a concrete beam helps meet a required reinforcement area. In reinforced concrete design, the steel must be arranged so the beam stays strong and uses material efficiently. This example uses a beam that needs a total steel cross-section of 4 square inches. The available bars in the example have a nominal diameter of 1.693 inches. Each bar provides a cross-sectional area of 2.25 square inches. When the engineer divides the required area by the area of one bar, the result is...

design example: sustainability in concrete building

design-example-sustainability-in-concrete-building

Green Features in a Concrete Building

A sustainable concrete building can use several green design features to save energy, water, and materials. Concrete is a flexible material for these choices, so it supports eco-friendly construction in commercial buildings. One strategy is to place a concrete parking area under the building. Open areas can use pervious concrete paver blocks, which let rainwater pass through and collect in an underground cistern. That stored water can then be reused for gardening, which improves water...

key terms and concepts

Learn how sand gradation affects concrete mix quality, workability, and cost. See how sieve analysis helps choose well-graded fine aggregate.

Choosing Well-Graded Sand for Concrete | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Molecular Models

Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models ...

Design Consideration

While designing a structure, the considerations start with the ultimate strength of a material, which is determined through tests, measuring changes under ...

Identify advantages and limitations of models such as their size, scale, properties, and materials.

BIO.2.A

Introduction to Statistics

The science of statistics involves collecting, analyzing, interpreting, and presenting data. The method of collecting, organizing, and summarizing data is ...

How Data are Classified: Categorical Data

A variable, usually notated by capital letters such as X and Y, is a characteristic or measurement that can be determined for each member of a population. ...

How Data are Classified: Numerical Data

Data that are countable or measurable in specific units are called numerical or quantitative data. Quantitative data are always numbers. Quantitative data ...

Correlations

Correlation means that there is a relationship between two or more variables (such as ice cream consumption and crime), but this relationship does not ...

Cause and Effect

While variables are sometimes correlated because one does cause the other, it could also be that some other factor, a confounding variable, is actually ...

Reliability and Validity

Reliability and validity are two important considerations that must be made with any type of data collection. Reliability refers to the ability to ...

Regression Toward the Mean

Regression toward the mean (&ldquo;RTM&rdquo;) is a phenomenon in which extremely high or low values&mdash;for example, and individual&rsquo;s blood ...

Measures of Central Tendency

The &quot;center&quot; of a data set is also a way of describing location. The two most widely used measures of the &quot;center&quot; of the data are the ...

variation-normal-distribution-range-and-standard-deviation

Variation: Normal Distribution, Range, and Standard Deviation

In the field of psychology, there are&nbsp;several ways to organize measurements of a trait, feature, or characteristic (i.e., variables). Qualitative ...

Statistical Significance

Once data is collected from both the experimental and the control groups, a statistical analysis is conducted to find out if there are meaningful ...

types-of-errors-detection-and-minimization

Types of Errors: Detection and Minimization

Error is the deflection of an obtained result from the expected or true results of an experiment. This happens due to the uncertainty associated with the ...

systematic-error-methodological-and-sampling-errors

Systematic Error: Methodological and Sampling Errors

Systematic errors, depending on their source, are of four types &#8211; sampling, instrumental, method, and personal errors.
Sampling errors occur due to ...

Random Error

Indeterminate or random errors arise from several uncontrollable variables in successive measurements.
Since these errors can neither be predicted nor ...

Standard Deviation of Calculated Results

A plot of relative deviation from the mean and its frequency of occurrence appears as a Gaussian curve. This probability distribution curve of a ...

Analyze data by identifying significant statistical features, patterns, sources of error, and limitations.

BIO.2.B

Numerical Calculations

In engineering applications, the representation of the numerical value is critical. Presenting or reporting the answer is one of the essential parts of ...

fundamental-mathematical-principles-pharmacokinetics-calculus

Fundamental Mathematical Principles in Pharmacokinetics: Calculus and Graphs

Pharmacokinetic models view drugs within the body as dynamic entities and rely on calculus as a vital tool for quantitative drug movement analysis.
...

fundamental-mathematical-principles-pharmacokinetics-mathematical

Fundamental Mathematical Principles in Pharmacokinetics: Mathematical Expressions and Units

Mathematical expressions help understand pharmacokinetic parameters by using equations to describe the relationships between different variables.
For ...

Quantitative Analysis

Quantitative analysis is a technique for measuring the amount of specific constituents in a sample. When the sample&#39;s composition is unknown, ...

Use mathematical calculations to assess quantitative relationships in data.

BIO.2.C

Experimental Designs

An experimental design is a systematic process that allows researchers to evaluate the relationship between dependent and independent variables. There are ...

from-theory-to-design-the-role-of-creativity-in-designing-experiments

From Theory to Design: The Role of Creativity in Designing Experiments

Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco&#8212;Monmouth University

Research studies come into being when a ...

design-example-strain-gauge-bridge-or-wheatstone-bridge

Design Example: Strain Gauge Bridge or Wheatstone Bridge

A strain gauge, a transducer that converts mechanical strain into electrical signals, is often used to measure force.
The engineer&#39;s role involves ...

The manager of a concrete plant needs to choose between two manufactured sand production facilities, A and B, to purchase sand that meets the required ...

Design Example: Distributing Reinforcements in Concrete Sections

Consider a reinforced concrete beam cross-section for which the required reinforcement cross-section equals 4 square inches according to the reinforcement ...

Evaluate experimental and engineering designs.

Scientific and engineering practices. The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

Choosing Well-Graded Sand for Concrete

Description

Transcript

Tags

More videos by Standards