CTEVT | Engineering Material | Diploma in Civil engineering | Question paper |1st year / 2nd part |3rd semester diploma in civil engineering
Engineering Material 2075 | Diploma in Civil Engineering
solution of Engineering Material, diploma in Civil Engineering 2075
1. a). What do you mean by the quarrying of stones? Describe the different process of quarrying of stones.
Quarrying of stones refers to the process of extracting natural stones from quarries or mines. These stones are typically used for various construction purposes, including building materials, landscaping, and decorative purposes. The process of quarrying stones involves several steps, which may vary depending on the type of stone and the geological characteristics of the quarry site. Here are the main processes involved:
- Prospecting: This is the initial stage where geologists or surveyors identify potential quarry sites based on the presence of suitable rock formations and the quality of the stone.
- Clearing the Site: Before quarrying can begin, vegetation, topsoil, and any other obstacles need to be removed from the site to expose the rock bed.
- Drilling and Blasting: In many cases, the stone is too large or embedded within the rock to be extracted directly. Therefore, holes are drilled into the rock using specialized drilling equipment. Explosives are then inserted into these holes and detonated to break the rock into smaller, more manageable pieces.
- Extraction: Once the rock has been fragmented, heavy machinery such as excavators, loaders, and dump trucks are used to remove the broken pieces of stone from the quarry site.
- Transportation: The extracted stones are transported from the quarry to processing plants or distribution centers using trucks, conveyor belts, or other means of transportation.
- Cutting and Dressing: Depending on the intended use of the stone, it may undergo further processing such as cutting, shaping, or polishing to achieve the desired size, shape, and finish.
1. b). Describe briefly the constituents of brick earth. explain the procedure for the compressive strength test for bricks.
Brick earth refers to the type of soil or clay used in the production of bricks. The constituents of brick earth typically include the following:
- Clay: Clay is the primary component of brick earth and provides cohesion and plasticity to the mixture. It helps the bricks maintain their shape and structure during molding and firing.
- Silt: Silt particles contribute to the overall workability of the brick-earth mixture. They help improve the texture and binding properties of the soil.
- Sand: Sand is often added to brick earth to improve its strength and reduce shrinkage during the drying and firing process. It also helps in achieving a smoother surface finish on the bricks.
- Organic Matter: Organic matter, such as decomposed plant material or humus, may be present in small amounts in brick earth. However, excessive organic content can lead to weaknesses in the bricks and may cause them to crack or deform during firing.
The compressive strength test for bricks is an important procedure to evaluate the strength and quality of bricks. Here's a brief explanation of the procedure:
- Sample Preparation: Select representative samples of bricks from the batch to be tested. The bricks should be clean, dry, and free from any visible defects. Remove any mortar adhering to the bricks.
- Conditioning: If the bricks are not already dry, they should be dried in an oven at a temperature of about 105°C to 115°C until they reach a constant weight. This ensures that the bricks are tested under consistent conditions.
- Testing Apparatus: The compressive strength test is typically performed using a compression testing machine. The machine consists of a hydraulic or mechanical loading system capable of applying a compressive load to the brick specimen.
- Test Setup: Place the brick specimen on the base of the testing machine in such a way that the load is applied along the longitudinal axis of the brick. Ensure that the specimen is properly aligned and centered.
- Loading: Gradually apply a compressive load to the brick specimen at a uniform rate until the brick fails. Record the maximum load applied to the brick and the corresponding failure load.
- Calculation: Calculate the compressive strength of the brick using the formula:
Compressive Strength = Maximum Load / Cross-sectional Area of the Brick
- Reporting: Report the compressive strength of the brick in units of pressure, such as megapascals (MPa) or newtons per square millimeter (N/mm²).
2.a. List out the classification of bricks. what are the qualities of good bricks?
Bricks can be classified into various types based on different criteria such as raw material composition, manufacturing process, and intended use. Here are some common classifications of bricks:
1. Based on Raw Material Composition:
- Clay Bricks: Made primarily from clay, often with additives like sand or shale.
- Sand Lime Bricks: Made from sand, lime, and water, typically produced by a chemical process involving steam curing.
2. Based on the Manufacturing Process:
- Extruded Bricks: Formed by forcing clay or other materials through a die to produce uniform shapes.
- Wire-cut Bricks: Produced by cutting clay into individual bricks using a wire cutter.
3. Based on Use:
- Facing Bricks: Used for exterior walls and facades due to their attractive appearance and durability.
- Engineering Bricks: Designed for structural applications requiring high strength and resistance to water absorption.
4. Based on Size:
- Standard Bricks: Have regular dimensions (e.g., 9" x 4.5" x 3").
- Modular Bricks: Slightly smaller in size to account for mortar joints.
Qualities of Good Bricks:
- Uniformity in Size and Shape: Good bricks should have consistent dimensions to ensure easy and uniform construction.
- Low Water Absorption: Bricks with low water absorption rates are less prone to damage from moisture and weathering.
- Soundness: Good bricks should produce a clear metallic sound when struck, indicating their solid and homogeneous structure.
- Durability: Bricks should be durable, capable of withstanding environmental factors and retaining their strength and appearance over an extended period.
- Fire Resistance: Bricks used in areas prone to fire should have high fire resistance to prevent structural damage.
- Eco-Friendly: Environmentally friendly bricks are those that use sustainable materials or production methods, minimizing environmental impact.
2. b) What are the characteristics of good building stone? define dressing and the purpose of dressing the stone.
Characteristics of good building stone:
- Strength: Building stones should have sufficient compressive strength to withstand the loads imposed on them without crumbling or breaking.
- Durability: Stones should be durable and able to withstand weathering, freeze-thaw cycles, and other environmental factors without significant deterioration.
- Hardness: Good building stones should be hard enough to resist abrasion and wear, ensuring long-term structural integrity.
- Density: Stones with higher density tend to be more durable and less porous, making them suitable for construction purposes.
- Workability: Stones should be easy to work with using common tools and techniques, allowing for precise cutting, shaping, and installation.
Dressing of stone refers to the process of shaping, smoothing, and finishing the surfaces of rough stone blocks to achieve the desired size, shape, and texture for construction purposes. The purpose of dressing stone includes:
- Improved Appearance: Dressing enhances the appearance of the stone by removing rough surfaces, irregularities, and imperfections, resulting in a smooth and uniform finish.
- Dimensional Accuracy: Dressing ensures that the stone blocks are cut to precise dimensions, facilitating proper alignment and fitting during construction.
- Enhanced Strength: Dressing removes weak or defective portions of the stone, improving its structural integrity and resistance to loading.
- Ease of Installation: Properly dressed stones are easier to handle and install, reducing labor and time requirements during construction.
- Better Bonding: Dressing creates flat and uniform surfaces on stone blocks, promoting better adhesion and bonding with mortar or other construction materials.
- Reduced Waste: Dressing minimizes waste by optimizing the use of stone blocks and reducing the need for additional trimming or cutting during construction.
3. a) List out the major steps involved in the manufacture of tiles. Explain briefly about the wall tiles and floor tiles.
The manufacture of tiles involves several major steps, regardless of the type of tile being produced. Here are the major steps involved:
- Raw Material Preparation: Raw materials such as clay, sand, feldspar, and other additives are collected and prepared according to the desired composition and properties of the tiles.
- Mixing: The raw materials are mixed in precise proportions to form a homogeneous mixture. Water may be added to achieve the desired consistency.
- Forming: The mixed raw materials are then formed into the desired shape and size of the tiles. This can be done through various methods such as pressing, extrusion, or molding.
- Drying: The formed tiles are dried to remove excess moisture. This is typically done in a controlled environment to prevent cracking or warping of the tiles.
- Decoration (Optional): Depending on the design requirements, the tiles may undergo additional processes such as glazing, painting, or printing to add decorative patterns or colors.
- Firing: The dried tiles are fired in a kiln at high temperatures to harden them and develop their final properties. This process is crucial for enhancing the strength and durability of the tiles.
- Quality Control: Throughout the manufacturing process, quality control measures are implemented to ensure that the tiles meet the required standards for size, shape, color, and strength.
- Packaging and Distribution: Once the tiles have been manufactured and inspected, they are packaged and prepared for distribution to retailers or customers.
Now, let's briefly explain wall tiles and floor tiles:
Wall Tiles:
Wall tiles are specifically designed for use on vertical surfaces such as walls in bathrooms, kitchens, and other interior spaces. They come in various sizes, shapes, and finishes to suit different aesthetic preferences and design requirements. Wall tiles are typically thinner and lighter than floor tiles, as they do not need to withstand heavy loads or foot traffic. They are often glazed to provide a smooth and waterproof surface that is easy to clean and maintain. Wall tiles can be made from ceramic, porcelain, glass, or natural stone, offering a wide range of options for interior decoration.
Floor Tiles:
Floor tiles are designed for use on horizontal surfaces such as floors in residential, commercial, and industrial buildings. They are subjected to heavy foot traffic, abrasion, and impact, so they need to be durable and resistant to wear. Floor tiles come in various materials including ceramic, porcelain, natural stone, and vinyl, each offering different levels of strength, durability, and aesthetics. Unlike wall tiles, floor tiles are thicker and heavier to withstand the loads imposed on them. They are available in a variety of sizes, textures, and finishes to provide traction and enhance safety, especially in wet areas such as bathrooms and kitchens. Proper installation and maintenance are essential to ensure the longevity and performance of floor tiles.
3. b) Explain the wet process of manufacturing cement with the help of a flow diagram
The wet process of manufacturing cement involves the following steps:
1. Raw Material Preparation:
Limestone (calcium carbonate) and clay (or shale) are crushed and mixed proportionately to obtain the raw meal.
2. Mixing and Grinding:
The raw meal is mixed with water to form a slurry.
The slurry is then fed into a ball mill along with limestone and gypsum additives.
The ball mill grinds the slurry to a fine powder, resulting in the formation of a homogenous mixture known as raw meal.
3. Burning (Calcination):
The raw meal is fed into a rotary kiln at high temperatures (typically around 1400-1500°C).
In the kiln, the raw materials undergo chemical reactions, including decomposition and fusion, to form clinker nodules.
4. Cooling:
The clinker nodules are cooled in a rotating cooler.
Air is blown through the cooler to reduce the temperature of the clinker to below 100°C.
5. Clinker Storage:
The cooled clinker is stored in clinker silos to await further processing.
6. Grinding of Clinker:
The clinker is finely ground with gypsum and other additives in a cement mill to produce cement powder.
7. Packaging and Distribution:
The cement powder is packaged in bags or bulk containers for distribution to customers.
Here's a flow diagram illustrating the wet process of manufacturing cement:
4 a). Describe various types of admixture and their uses.
Admixtures are substances added to concrete or mortar to modify their properties, either during mixing or shortly before or during placement. They are used to enhance the performance of concrete in various ways. Here are various types of admixtures and their uses:
1. Water-Reducing Admixtures (Plasticizers):
- These admixtures reduce the amount of water needed in the concrete mix without affecting workability.
- They improve workability, reduce segregation and bleeding, and increase the strength of concrete.
2. Retarding Admixtures:
- Retarding admixtures slows down the setting time of concrete, allowing more time for placing and finishing.
- They are particularly useful in hot weather or large-scale placements.
3. Accelerating Admixtures:
- Accelerating admixtures speeds up the setting and early strength development of concrete.
- They are beneficial in cold weather concreting or when rapid construction schedules are required.
- Calcium chloride is a commonly used accelerating admixture.
4. Air-Entraining Admixtures:
- Air-entraining admixtures are added to concrete to produce microscopic air bubbles in the mix.
- These air bubbles provide resistance to freeze-thaw damage by allowing the expansion of water during freezing.
- They improve workability, reduce bleeding, and enhance the durability of concrete.
5. Superplasticizers (High-Range Water Reducers):
- Superplasticizers are highly effective water-reducing admixtures that significantly improve the workability of concrete without increasing water content.
- They allow for the production of high-strength, high-performance concrete mixes with low water-cement ratios.
- Superplasticizers are commonly used in precast concrete production, high-performance concrete, and self-consolidating concrete.
6. Pozzolanic Admixtures:
- Pozzolanic admixtures are added to concrete to improve its durability and reduce permeability.
- They react with calcium hydroxide in the presence of moisture to form additional cementitious compounds, enhancing strength and reducing shrinkage.
- Common pozzolanic materials include fly ash, silica fume, and slag.
7. Corrosion-Inhibiting Admixtures:
- Corrosion-inhibiting admixtures are added to concrete to protect embedded steel reinforcement from corrosion.
- They create a protective film on the surface of the reinforcement, preventing the ingress of chloride ions and reducing the risk of corrosion.
8. Shrinkage-Reducing Admixtures:
- Shrinkage-reducing admixtures are used to minimize drying shrinkage in concrete, reducing the risk of cracking.
- They work by reducing the surface tension of water in the concrete mix, allowing for more complete hydration and reducing internal stresses.
Engineering Material 2074 | Diploma in Civil Engineering
Engineering Material 2073 | Diploma in Civil Engineering
Engineering Material 2075 | Diploma in Civil Engineering
Engineering Material 2074 | Diploma in Civil Engineering
