Basic Civil And Mechanical Engineering PDF

Swarnandhra College of Engineering & Technology (Autonomous) Seetharampuram, NARSAPUR, W.G. Dt., 534 280. Department of Civil Engineering BASIC CIVIL AND MECHANICAL ENGINEERING (23ES1T01)...

Swarnandhra College of Engineering & Technology (Autonomous) Seetharampuram, NARSAPUR, W.G. Dt., 534 280. Department of Civil Engineering BASIC CIVIL AND MECHANICAL ENGINEERING (23ES1T01) - Dr M.S.V.K.V.PRASAD UNIT-I Basics of Civil Engineering SYLLABUS: Role of Civil Engineers in Society- Various Disciplines of Civil Engineering- Structural Engineering- Geo-technical Engineering- Transportation Engineering - Hydraulics and Water Resources Engineering - Environmental Engineering-Scope of each discipline. Building Construction and Planning- Construction Materials- Cement - Aggregate - Bricks- Cement concrete- Steel. Introduction to Prefabricated construction Techniques *************************************************************************************** INTRODUCTION TO CIVIL ENGINEERING:-  Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewage systems, pipelines, structural components of buildings, and railways.  Civil engineering is traditionally broken into a number of sub-disciplines. Civil engineering is the application of physical and scientific principles for solving the problems of society, and its history is intricately linked to advances in the understanding of physics and mathematics throughout history.  Because civil engineering is a broad profession, including several specialized sub-disciplines, its history is linked to knowledge of structures, materials science, geography, geology, soils, hydrology, environmental science, mechanics, project management and other fields. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& UNIT-1.A. 1. Explain the various contributions of civil engineers to the welfare of the society? ANS: 1. Civil engineer will work on planning, design, construction and maintenance of projects such as roads, buildings, dams, bridges, sewages and water supply systems. 2. Civil engineering is about community service, development, and improvement. 3. Civil engineers often use theory and models to predict how a design will perform. 4. Civil engineers test their ideas on field without endangering life. 5. Civil engineers develop infrastructure for the society which is the backbone of the society. 6. Civil engineers increase the health and quality of life by developing better water supply, sewage systems, and waste water plants, to protect from natural hazards and provide health care. 7. Civil engineers improve agriculture through water management systems and distribution projects. 8. Civil engineers provide solution for the rapid and dramatic changes of transportation. 9. Structural engineers deals with connections design, analysis and construction of components to resist loads from internal and external forces. 10. As a structural engineer, you will face the challenge of analyzing and designing structures to ensure that they safely perform their purpose. 11. They must support their own weight and resist dynamic environmental loads such as hurricanes, earthquakes, blizzards, and floods. 12. Stadiums, arenas, skyscrapers, offshore oil structures, space platforms, amusement park rides, bridges, office buildings, and homes are a few of the many types of projects in which structural engineers are involved 13. Structural engineers develop new materials other than steel and cements which with stand more loads & have high strength by weight ratio which includes FRP, polymers, etc,. 14. Geotechnical engineers apply the knowledge about the behavior of soils and its composition for design of Foundations, retaining walls, earth dams, clay liners and geo synthetics for waste condiments. 15. Examples of facilities in the earth are tunnels, deep foundations, and pipelines. Highway pavements and many buildings are supported on the earth. 1 16. Transportation plays and essential role in the development of the society by providing trade routes and harbors air routes etc,. 17. Civil engineers plan, design, built, operate and maintain these of transport. 18. Civil engineers provide safe, efficient and convenient movement of people and goods 19. Civil engineers consider the forces and movements, weight and stress of the vehicles in motion and centrifugal forces at curves while the design the transportation. 20. The collection, storage, treatment, transmission and distribution of water played a significant role in urbanization, population growth and commercial agriculture and land use. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 2. What is the ROLE OF CIVIL ENGINEERS in society? ANS: A civil engineer has to conceive, plan, estimate, get approval, create and maintain all civil engineering activities. Civil engineer has very important role in the development of the following infrastructure: 1. Measure and map the earth‟s surface. 2. Plan new townships and extension of existing towns. 3. Build the suitable structures for the rural and urban areas for various utilities. 4. Build tanks and dams to exploit water resources. 5. Build river navigation and flood control projects. 6. Build canals and distributaries to take water to agricultural fields. 7. Purify and supply water to the needy areas like houses, schools, offices etc. 8. Provide and maintain communication systems like roads, railways, harbors and airports. 9. Devise systems for control and efficient flow of traffic. 10. Provide and maintain solid and waste water disposal system. 11. Monitor land, water and air pollution and take measures to control them. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 3. Briefly explain Structural Engineering and its scope. ANS: Broad disciplines of Civil Engineering: Civil engineering is a wide field and includes many types of structures such as residential buildings, public buildings, industrial buildings, roads, bridges, tunnels, railways, dams, canals, airports, harbours, waste water treatment plants, water supply networks and drainage networks, drainage networks etc. According to the type of structures and activities carried out, main branches of civil engineering are classified as follows: 1. Structural Engineering 2. Geotechnical Engineering 3. Transportation Engineering 4. Environmental Engineering 5. Water resources Engineering Structural Engineering 1. Before building a structure, it should be analyzed and designed to decide about its size to resist the possible forces coming on it. 2. The structure should be safe and at the same time its components should be as small as possible. 3. Need of tall structures and improvements in computers gave rise to matrix method and finite element method of analysis. 4. Disasters due to earthquakes have made civil engineers to study earthquake forces and build earthquake resistant structures. 5. It needs the knowledge of structural dynamics. 6. A civil engineer has to not only give a safe structure but he has to give an economical structure also. 7. Hence, there is need for studying mathematical optimization techniques. 2  8. All these aspects of analysis and design fall under structural engineering field. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 4. Briefly explain Geotechnical Engineering and its scope? ANS: Geotechnical Engineering 1. All structures have to finally transfer the load acting on them to soil safely. 2. Soil property changes from place to place. Even in the same place it may not be uniform at different depth and in different seasons. 3. Hence, a civil engineer has to properly investigate soil and decide about the safe load that can be spread on the soil. This branch of study in civil engineering is known as geotechnical engineering. 4. Apart from finding safe bearing capacity for foundation of buildings, geotechnical engineering involves various studies required for the design of pavements, tunnels, earthen dam, canals and earth retaining structures. 5. It involves study of ground improvement techniques also. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 5. Briefly explain Hydraulics, Water Resources engineering and its scope? ANS: Hydraulics, Water Resources Engineering 1. Water is an important need for all living beings. Study of mechanics of water and its flow characteristics is another important field in civil engineering and it is known as hydraulics. 2. Requirement of water in cities for domestic purpose and for industries is continuously increasing. 3. Rural areas need water for agricultural field also. Hence civil engineers have to look for new water resources and for storing them. This branch of civil engineering is known as water resources engineering. 4. Water stored in reservoirs by building bunds and dams should be brought to agricultural fields through canals and distributaries. 5. Study connected with this aspect is known as irrigation engineering. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 6. Briefly explain Environmental Engineering and its scope? ANS: Environmental Engineering 1. Apart from tackling solid and waste water disposal civil engineers have to tackle air pollution problem also. Due to industrialization air pollution is becoming a major problem. 2. It is estimated that for every tone of cement produced one tone of CO2 is released to environment. Vehicles also produce lot of CO2. 3. During the last one century, the environmental pollution has resulted in global warming by 4°C. 4. An environmental disaster will be unavoidable if China, India and other developing countries start consuming as much energy and materials as the West did it in its march to industrialization. 5. Hence environmental engineering is emerging as an important field of study in civil engineering. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 7. Briefly explain Transportation Engineering and its scope? ANS: Transportation Engineering 1. Transportation facility is another important need. Providing good and economical road links is an important duty of civil engineers. 2. It involves design and construction of base courses, suitable, surface finishes, cross drainage works, intersections, culverts, bridges and tunnels etc. 3  3. Railways are another important long-way transport facility. 4. Design, construction and maintenance of railway lines are parts of transportation engineering. 5. Globalization has resulted into requirement of airports and harbors. 6. For proper planning of these transport facilities, traffic survey is to be carried out. 7. Carrying out traffic survey and then planning, designing, construction and maintenance of roads, railways, bridges, tunnels, airports and harbors is known as transportation engineering. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 8. Write short note on impact of infrastructure development on the economy of the country. ANS: Civil engineering activities in the infrastructural development are: (i) Good planning of towns and extension areas in the cities. Each extension area should be self- sufficient in accommodating offices, educational institutions, markets, hospitals, recreational facilities and residential accommodation. (ii) Assured water supply. (iii) A good drainage system. (iv) Pollution free environnemental conditions. (v) A well planned and built network of roads and road crossings. (vi) Railways connect to all important cities and towns. (vii) Airports and harbor of national and international standards. (viii)Infrastructure also involves electricity supply, without assured electric supply no city town can develop. (ix)Internet and telephones are also desirable features. (x)Educational facility also forms part of infrastructure. Proximity of good primary and secondary schools to residential areas is desirable. (xi)Collegiate and professional education also forms part of infrastructure of a city. (xii)Good health care facility is a necessity. Primary health centers, specialized hospitals and doctors add to the desirable infrastructure facility. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& UNIT-1.B - Building Construction and Planning 9. What is meant by Building Construction and Planning? ANS: Building construction and planning is the process of constructing buildings, whether residential, commercial, or industrial, requires meticulous planning, design, and execution to ensure safety, functionality, and sustainability. The Importance of Building Construction 1. Infrastructure Development: Building construction is at the core of infrastructure development. It includes the creation of roads, bridges, airports, and other vital facilities that connect communities and enable economic activities. The quality and efficiency of these structures have a direct impact on transportation, trade, and overall regional development. 2. Shelter and Housing: One of the primary functions of building construction is providing shelter and housing for the population. Affordable and well-designed housing is essential for a high quality of life and social well-being. It not only meets the basic human need for shelter but also fosters a sense of security and belonging. 3. Economic Growth: Construction activities stimulate economic growth by creating jobs, promoting local industries, and attracting investments. A thriving construction sector contributes to the Gross Domestic Product (GDP) and supports various related industries, such as manufacturing and real estate. 4. Environmental Considerations: In recent years, there has been a growing emphasis on environmentally friendly construction practices. Sustainable building construction focuses on reducing energy consumption, minimizing waste, and using eco-friendly materials. These practices not only conserve natural resources but also reduce greenhouse gas emissions. 4 The Role of Planning in Building Construction 1. Land Use and Zoning: Urban planning plays a crucial role in determining land use and zoning regulations. Proper zoning ensures that land is used efficiently and that residential, commercial, and industrial areas are appropriately segregated. Zoning also promotes mixed-use developments that can reduce traffic congestion and promote walkability. 2. Safety and Resilience: Planning involves considering the safety and resilience of buildings and infrastructure. Designing structures that can withstand natural disasters like earthquakes, floods, and hurricanes is essential for protecting lives and property. Adequate planning can also help mitigate the impacts of climate change on urban areas. 3. Aesthetics and Design: Urban planning considers the aesthetics and design of buildings and public spaces. Well-designed cities and neighborhoods enhance the quality of life, promote cultural identity, and encourage tourism. Thoughtful planning can preserve historical landmarks and promote innovative architectural designs. 4. Transportation and Accessibility: Planning encompasses transportation systems and accessibility. Efficient public transportation networks, pedestrian-friendly streets, and bicycle lanes can reduce traffic congestion, air pollution, and energy consumption. These elements contribute to a more sustainable and livable urban environment. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 10. Write about different construction materials? ANS: Construction materials are the materials used to construct buildings, roads, and other infrastructure. Construction materials must be strong and durable to withstand the forces of construction and use. They must also be able to resist weathering and other environmental effects. The construction materials list includes cement, steel, sand, concrete, ready-mix concrete, binding wires, aggregates, bricks, blocks, etc. apart from these, various eco-friendly construction materials are also used in building construction. 1. Cement Cement is a binder, a substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used but rather to bind sand and gravel together. Cement companies produced mixed with fine aggregate to make mortar for masonry, or with sand and gravel for concrete. 2. Steel Structural steel is a popular construction material used alongside concrete to create impressive and long- lasting buildings. Its versatility, sustainability, and flexibility are the main reasons for its use and cost- effectiveness. Steel reinforcement bars or rebars are used to improve the tensile strength of the concrete since concrete is fragile in tension but is strong in compression. Steel is only used as rebar because of the elongation of steel due to high temperatures (thermal expansion coefficient) nearly equal to that of concrete. 3. River sand or Natural sand The sand should be white-grey and is one of the fine-graded sands used to construct buildings. They are mainly used in concrete and masonry work. They can also be used for RCC, plastering, and other brick or block works. 4. Concrete Concrete is the most widely used construction material in the entire world. These materials include cement, water, fine aggregate, and crushed stones or gravel. Sand and gravel or crushed stones are fine aggregate and coarse aggregate, respectively. 5. Binding wires Binding Wire is used for tying applications in the field of construction. It is used extensively in the construction sector to tie the rebars at the joints to keep the structure intact. Binding wire is also called annealed wire and is made of mild steel. 6. Fly Ash Fly ash is a refined powder byproduct of burning pulverized coal in electric power plants. Fly ash is a pozzolan, a substance containing aluminous and siliceous material that forms cement in the presence of 5 water. Fly ash can be used as prime material in many cement-based products, such as poured concrete, concrete block, and brick. 7. Aggregate – Construction Materials Construction aggregate, or simply aggregate, is a broad category of coarse to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete, and geosynthetic aggregates. Aggregates are the most mined materials in the world. 8. Bricks A brick is a type of block used to build walls, pavements, and other elements in masonry construction. Appropriately, the term brick denotes a block composed of dried clay but is now also used informally to indicate other chemically cured construction blocks. 9. Timber (Wood) Timber is used indoors, in the windows, cabinets, cupboards, shelves, tables, railings, etc. Timber is also popularly used in the form of plywood & raw wood. Products like ply blocks and ply boards, heavy patterned doors, and windows are made of solid wood/timber to provide strength, toughness, and durability. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 11. List out various types of classification of rocks, giving examples of each? ANSWER The rocks may be classified on the basis of their geological formation, physical characteristics and chemical composition as shown in Fig. Igneous Rocks: Igneous rocks are of volcanic origin and are formed as a result of solidification of molten mass lying below or above the earth‟s surface. The inner layers of the earth are at a very high temperature causing the masses of silicates to melt. This molten mass called magma is forced up as volcanic eruptions and spreads over the surface of earth where it solidifies forming basalt and trap. These are known as effusive rocks. Examples are Quartz, Monzonite Sedimentary Rock: These are also known as aqueous or stratified rocks. The various weathering agencies, e.g. rain, sun, air, frost, etc. break up the surface of earth. Rain water carries down these broken pieces to the rivers. As the rivers descend down to the plains, the velocity decreases gradually and the sediments (disintegrated rock pieces, sand, silt, clay, debris, etc.) in the water settle. Examples are shale, limestone, sandstone, siltstone, and conglomerate. Metamorphic Rock: These are formed from igneous or sedimentary rocks as a result of the action of the earth movements, temperature changes, liquid pressures, etc. The resultant mass may have a foliated structure, e.g. slate, gneiss, schist and phyallite or non-foliated structure, e.g. marble, quartzite and serpentine. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 12. Explain in detail the composition and manufacture process of good bricks using a flow chart? ANS:  For the preparation of bricks, clay or other suitable earth or soil is moulded to the desired shape after subjecting it to several processes. After drying, it should not shrink and no crack should develop.  The clay used for brick making consists mainly of silica and alumina mixed in such a proportion that the clay becomes plastic when water is added to it. 6   It also consists of small proportions of lime, iron, manganese, sulphur, etc. The proportions of various ingredients are as follows: The operations involved in the manufacture of clay bricks are represented diagrammatically in below figure. PREPARATION OF BRICK: It consists of the following operations. 1. Unsoiling: The soil used for making building bricks should be processed so as to be free of gravel, coarse sand (practical size more than 2 mm), lime and kankar particles, organic matter, etc. About 20 cm of the top layer of the earth, normally containing stones, pebbles, gravel, roots, etc., is removed after clearing the trees and vegetation. 2. Digging: After removing the top layer of the earth, proportions of additives such as fly ash, sandy loam, rice husk ash, stone dust, etc. should be spread over the plane ground surface on volume basis. The soil mass is then manually excavated, watered and left over for weathering and subsequent processing. The digging operation should be done before rains. 3. Weathering: Stones, gravels, pebbles, roots, etc. are removed from the dug earth and the soil is heaped on level ground in layers of 60–120 cm. The soil is left in heaps and exposed to weather for at least one month in cases where such weathering is considered necessary for the soil. This is done to develop homogeneity in the mass of soil, particularly if they are from different sources, and also to eliminate the impurities which get oxidized. 4. Blending: The earth is then mixed with sandy-earth and calcareous-earth in suitable proportions to modify the composition of soil. Moderate amount of water is mixed so as to obtain the right consistency for moulding. The mass is then mixed uniformly with spades. Addition of water to the soil at the dumps is necessary for the easy mixing and workability, but the addition of water should be controlled in such a way that it may not create a problem in moulding and drying. Excessive moisture content may effect the size and shape of the finished brick. 7 5. Tempering: Tempering consists of kneading the earth with feet so as to make the mass stiff and looks like plastic. For manufacturing good brick, tempering is done in pug mills and the operation is called pugging. The yield from a pug mill is about 1500 bricks. 6. Moulding: It is a process of giving a required shape to the brick from the prepared brick earth. Moulding may be carried out by hand or by machines. The process of moulding of bricks may be the soft-mud (hand moulding), the stiff-mud (machine moulding) or the dry press process (moulding using maximum 10 per cent water and forming bricks at higher pressures). Fire- brick is made by the soft mud process. Roofing, floor and wall tiles are made by dry-press method. However, the stiff-mud process is used for making all the structural clay products. a. Hand Moulding b. Ground Moulding c. Table Moulding d. Machine Moulding 7. Drying: The object of drying is to remove the moisture to control the shrinkage and save fuel and time during burning. The drying shrinkage is dependent upon pore spaces within the clay and the mixing water. Clay products can be dried in open air driers or in artificial driers. The artificial driers are of two types, the hot floor drier and the tunnel drier. In the former, heat is applied by a furnace placed at one end of the drier or by exhaust steam from the engine used to furnish power and is used for fire bricks, clay pipes and terracotta. Tunnel driers are heated by fuels underneath, by steam pipes, or by hot air from cooling kilns. They are more economical than floor driers. In artificial driers, temperature rarely exceeds 120°C.The time varies from one to three days. In developing countries, bricks are normally dried in natural open air driers. 8. Burning of Bricks: Kiln Burning: The kiln used for burning bricks may be underground, e.g. Bull‟s trench kiln or over ground, e.g. Hoffman‟s kiln. These may be rectangular, circular or oval in shape. When the process of burning bricks is continuous, the kiln is known as continuous kiln, e.g. Bull‟s trench and Hoffman‟s kilns. On the other hand if the process of burning bricks is discontinuous, the kiln is known as intermittent kiln. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 13. What are the different tests conducted on bricks and uses of bricks? ANS: The following are the required properties of good bricks: (i) Colour: Colour should be uniform and bright. (ii) Shape: Bricks should have plane faces. They should have sharp and true right angled corners. (iii) Size: Bricks should be of standard sizes as prescribed by codes. (iv)Texture: They should possess fine, dense and uniform texture. They should not possess fissures, cavities, loose grit and unburnt lime. (v) Soundness: When struck with hammer or with another brick, it should produce metallic sound. (vi) Hardness: Finger scratching should not produce any impression on the brick. (vii) Strength: Crushing strength of brick should not be less than 3.5 N/mm2. A field test for strength is that when dropped from a height of 0.9 m to 1.0 mm on a hard ground, the brick should not break into pieces. (viii) Water Absorption: After immersing the brick in water for 24 hours, water absorption should not be more than 20 per cent by weight. For class-I works this limit is 15 per cent. (ix) Efflorescence: Bricks should not show white patches when soaked in water for 24 hours and then allowed to dry in shade. White patches are due to the presence of sulphate of calcium, magnesium and potassium. They keep the masonry permanently in damp and wet conditions. (x) Thermal Conductivity: Bricks should have low thermal conductivity, so that buildings built with them are cool in summer and warm in winter. (xi) Sound Insulation: Heavier bricks are poor insulators of sound while light weight and hollow bricks provide good sound insulation. (xii) Fire Resistance: Fire resistance of bricks is usually good. In fact bricks are used to encase steel columns to protect them from fire. 8 Uses of Bricks Bricks are used in the following civil works: (i) As building blocks. (ii) For lining of ovens, furnaces and chimneys. (iii) For protecting steel columns from fire. (iv) As aggregates in providing water proofing to R.C.C. roofs. (v) For pavers for footpaths and cycle tracks. (vi) For lining sewer lines. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 14. What is an aggregate, Write about different types of aggregates, their uses, also discuss about different properties of aggregates? ANS: Aggregate is hard material made up of rock materials. It consists of many types, that include gravel, concrete, crushed rock, etc. It is used in the construction of buildings, construction of pavement surfaces, etc. These aggregates can be used for making concrete with the proper mixing of sand and cement. The properties of the aggregates will be different for different sizes of aggregates. Aggregates can be of many types based on the different parameters. These parameters can be shape, size, strength, etc. Based on the size of the aggregates, they can broadly be classified as 1. Fine aggregate 2. Coarse aggregate 1. Fine aggregate: This is the aggregate for which its size ranges between 4.75 mm to 0.075 mm. These are also called sand. These are the natural particles that the mining process can generate. It consists of the particle of the crushed stone or the sandy material. 2. Coarse aggregate: These aggregates have a size of more than 4.75 mm. These aggregates are used in the construction of concrete structures. Such aggregates include river gravel and stone particles made from rock stratum. Uses of Aggregate Aggregates have many uses in the construction of various structures. Aggregates are used to construct buildings, railway bridges, dams and other concrete structures. Using aggregates in concrete structures helps to bind the other ingredients in the concrete structures. Aggregate enhances the strength of the concrete structures. The crushing strength of concrete is enhanced by using aggregate material. It increases the compactness of the aggregate. Its uses in concrete structures reduce the cement quantity in the concrete. Aggregates are used in different sizes in the concrete mix based on the required strength and compactness.  Aggregates provide more strength to the concrete.  The use of aggregates in concrete structures increases the compactness of the structures.  The use of aggregate reduces the quantity of cement in the concrete mix.  It also reduces the water requirement in the concrete mix.  It reduces the shrinkage of concrete in the dry mix.  It reduces the voids in the concrete. Different properties of aggregates 1. Size: Aggregates come in various sizes, from fine particles smaller than 4.75mm to large rocks over 152 mm in diameter. The size of the aggregate affects its workability, durability, and strength. 2. Shape: Aggregates can be angular, rounded, or irregular in shape. Angular aggregates provide better interlocking, while rounded aggregates offer better workability. The shape of the aggregate affects the strength and durability of the resulting material. 3. Specific gravity: Specific gravity is the ratio of the weight of a substance to the weight of an equal volume of water. The specific gravity of aggregates is important for determining the weight of materials needed for a project. 4. Absorption: Aggregates have varying levels of porosity, which affects their ability to absorb water. Aggregates with high absorption rates can increase the risk of cracking and other types of damage in the resulting material. 9 5. Strength: The strength of aggregates is determined by their resistance to crushing and impact. The strength of the aggregate affects the strength and durability of the resulting material. 6. Durability: Aggregates must be able to withstand environmental factors such as freezing and thawing cycles, exposure to moisture, and other types of wear and tear. The durability of the aggregate affects the durability of the resulting material. 7. Cleanliness: Aggregates should be free from organic matter, clay, silt, and other types of impurities that can affect the strength and durability of the resulting material. 8. Grading: The grading of aggregates refers to the distribution of sizes within a batch. Proper grading ensures that the resulting material has the right workability, strength, and durability. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 15. Discuss about different tests on Aggregates? ANS: Different types of tests are carried out on the aggregate to determine its properties like strength, durability, corrosion resistance, hardness, etc. Here are some tests on aggregates mentioned below: 1. Crushing test: This test is carried out to determine the aggregate's crushing strength according to IS code 2386 (part IV) 1963. The crushing value of an aggregate indicates the resistance against the crushing of the aggregates. If the crushing value of the aggregate is on or above 35, it will be considered a weak aggregate. 2. Abrasion test: Los angles abrasion test is carried out to know the abrasion resistance of the coarse aggregate. It determines the percentage wear of the aggregate due to relative rubbing. It also indicates the hardness property of the aggregates. 3. Impact test: Aggregate may be supposed to impact load during its life cycle, so it's important to get the impact strength of the aggregate. It measures the strength of the aggregate against the impact load acting over the aggregate. It indicates the toughness of the aggregate. 4. Soundness test: This test indicates the durability of the aggregate. It also indicates the aggregate's resistance property against adverse weather conditions. 5. Shape test: This test is carried out to know the shape of the aggregate. The flakiness index and elongation index are the main important parameters to define the shape of the aggregates. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 16. What are the properties and uses of cement? Or Write about the various ingredients of Portland cement along with their functions? ANS:  Cement is broadly described as material having adhesive and cohesive property with capacity to bond the material like stone, bricks, building blocks etc.  James Parker developed cement from clay minerals and calcium carbonate and patented as Roman cement in 1796.  Cement is a binder, a substance that sets and hardens independently, and can bind other materials together. Cements are inorganic material that shows the cementing properties of setting and hardening when mixed with water.  Cement is prepared from calcareous (Ca) material and argillaceous (Al + Si) material.  Cement has property of setting and hardening under water by virtue of chemical reaction of hydrolysis and hydration.  Cement is used for structural construction like buildings, roads, bridges, dam etc. Properties of cement:  It gives strength to the masonry works.  It is an excellent binding material.  It is easily workable  It offers good resistance to the moisture  It possesses a good plasticity.  It hardens early. Uses of cement:  Cement mortar for masonry works 10   Cement Concrete for laying floors, roofs, lintels, beams, stairs, pillars etc  Construction of important engineering structures such as Bridges  Culverts, Dams, Tunnels, Storage reservoirs, Docks etc  Making Cement Pipes  Manufacture of precast pipes, dust bins, fencing posts etc. Composition of various ingredients of Portland cement along with their functions cement:- The Portland cement consists of the following chemicals  Lime - CaO- 62%  Silica –SiO2-22%  Alumina - Al2O3 -5%  Calcium sulphate-CaSO4-4%  Iron Oxide-Fe2O3-3%  Magnesia-MgO-2%  Sulphur-S-1%  Alkaline and other material-1% Portland cement is actually a chemically complex material composed of 4 major compounds (phases): Tricalcium silicate (Ca3SiO5) Dicalcium silicate (Ca2SiO4) Tricalcium aluminate (Ca3Al 2O6) Tetracalcium aluminoferrite (Ca4Al 2Fe2O10) Each contributes different properties to the cement. Tricalcium silicate (C3S) hydrates and hardens fairly quickly and is largely responsible for initial setting and early strength gain. Dicalcium silicate (C2S) hydrates and hardens slowly and is largely responsible for long-term strength gain. Tricalcium aluminate (C3A) hydrates and hardens the quickest, liberating a large amount of heat in the process. It is primarily responsible for setting. Gypsum is added to portland cement to retard C3A hydration. Without the gypsum, C3A hydration would cause the portland cement to set almost immediately after adding water. C3A reacts poorly when exposed to sulfates (MgSO4 and NaSO4 salts) that naturally occur in groundwater, seawater, and some clayey soils. The reaction causes the concrete to expand and crack. Sulfate resistance cement has a low C3A concentration. Tetracalcium aluminoferrite (C4AF) hydrates rapidly but contributes very little to setting or strength gain. Its presence allows for lower kiln temperatures in the manufacturing process, which is why ferrous materials are added to the raw ingredients. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 17. Describe the process of manufacture of cement with a neat diagram? Or Discuss the various ingredients of Portland cement along with their functions? ANS: There are four stages in the manufacture of Portland cement: (1) Crushing and grinding the raw materials (2) Blending the materials in the correct proportions (3) Burning the prepared mix in a kiln (4) Grinding the burned product, together with some 5%of gypsum The first three processes of manufacture are known as the wet, dry, and semidry processes and are so termed when the raw materials are ground wet and fed to the kiln as slurry, ground dry and fed as a dry powder, or ground dry and then moistened to form nodules that are fed to the kiln. 11 1. Crushing and grinding  All except soft materials are first crushed, often in two stages, and then ground, usually in a rotating cylindrical ball, or tube mills containing a charge of steel grinding balls.  This grinding is done wet or dry, depending on the process in use, but for dry grinding the raw materials first may need to be dried in cylindrical, rotary dryers.  Soft materials are broken down by vigorous stirring with water in wash mills, producing fine slurry, which is passed through screens to remove oversize particles. 2. Blending  Finer control is obtained by drawing material from two or more batches containing raw mixes of slightly different composition.  In the dry process these mixes are stored in “silos”, slurry tanks are used in the wet process.  Thorough mixing of the dry materials in the silos is ensured by agitation and vigorous circulation induced by compressed air.  In the wet process the slurry tanks are stirred by mechanical means or compressed air or both.  The slurry, which contains 35 to 45% water, is sometimes filtered, reducing the water content to 20 to 30%, and the filter cake is then fed to the kiln.  This reduces the fuel consumption for burning. 3. Burning  The dominant means of burning is the rotary kiln. These kilns up to 200 meters (660 feet) long and 6 meters in diameter in wet process plants but shorter for the dry process, consist of a steel, cylindrical shell lined with refractory materials.  They rotate slowly on an axis that is inclined a few degrees to the horizontal. The raw material feed, introduced at the upper end, moves slowly down the kiln to the lower, or firing, end.  The fuel for firing may be pulverized coal, oil, or natural gas injected through a pipe. The temperature at the firing end ranges from about 1,350 to 1,550°C (2,460 to 2,820°F), depending on the raw materials being burned.  The burned product emerges from the kiln as small nodules of clinker. These pass into coolers, where the heat is transferred to incoming air and the product cooled.  The clinker may be immediately grinded to cement or stored in stockpiles for later use. Modern cement plants are equipped with elaborate instrumentation for control of the burning process.  The largest rotary kilns have outputs exceeding 5,000 tons per day. 4. Grinding  The clinker and the required amount of gypsum are grinded to a fine powder in horizontal mills similar to those used for grinding the raw materials.  The material may pass straight through the mill (open-circuit grinding), or coarser material may be separated from the ground product and returned to the mill for further grinding (closed-circuit grinding). 12   Sometimes a small amount of a grinding aid is added to the feed material. For air-entraining cements the addition of an air-entraining agent is similarly made.  Finished cement is pumped pneumatically to storage silos from which it is drawn for packing in paper bags or for dispatch in bulk containers. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 18. Discuss about different tests conducted on cement? ANS: Basically two types of tests are under taken for assessing the quality of cement. These are either field test or lab tests. The current section describes these tests in details. 1. Field test: There are four field tests may be carried out to as certain roughly the quality of cement.There are four types of field tests to access the colour, physical property, and strength of the cement as described below. a. Colour  The colour of cement should be uniform.  It should be typical cement colour i.e. grey colour with a light greenish shade. b. Physical properties  Cement should feel smooth when touched between fingers.  If hand is inserted in a bag or heap of cement, it should feel cool. c. Presence of lumps  Cement should be free from lumps.  For a moisture content of about 5 to 8%, this increase of volume may be much as 20 to 40 %, depending upon the grading of sand. d. Strength  A thick paste of cement with water is made on a piece of thick glass and it is kept under water for 24 hours. It should set and not crack. 2. Laboratory tests: Six laboratory tests are conducted mainly for assessing the quality of cement. These are: fineness, compressive strength, consistency, setting time, soundness and tensile strength. 1. Fineness  This test is carried out to check proper grinding of cement.  The fineness of cement particles may be determined either by sieve test or permeability apparatus test.  In sieve test, the cement weighing 100 gm is taken and it is continuously passed for 15 minutes through standard BIS sieve no. 9.The residue is then weighed and this weight should not be more than 10% of original weight.  In permeability apparatus test, specific area of cement particles is calculated. This test is better than sieve test. The specific surface acts as a measure of the frequency of particles of average size. 2. Compressive strength  This test is carried out to determine the compressive strength of cement.  The mortar of cement and sand is prepared in ratio 1:3.  Water is added to mortar in water cement ratio 0.4.  The mortar is placed in moulds. The test specimens are in the form of cubes and the moulds are of metals. For 70.6 mm and 76 mm cubes, the cement required is 185gm and 235 gm respectively.  Then the mortar is compacted in vibrating machine for 2 minutes and the moulds are placed in a damp cabin for 24 hours.  The specimens are removed from the moulds and they are submerged in clean water for curing.  The cubes are then tested in compression testing machine at the end of 3days and 7 days. Thus compressive strength was found out. 3. Consistency  The purpose of this test is to determine the percentage of water required for preparing cement pastes for other tests.  Take 300 gm of cement and add 30 percent by weight or 90 gm of water to it. 13   Mix water and cement thoroughly.  Fill the mould of Vicat apparatus and the gauging time should be 3.75 to 4.25 minutes.  Vicat apparatus consists of a needle is attached a movable rod with an indicator attached to it.  There are three attachments: square needle, plunger and needle with annular collar.  The plunger is attached to the movable rod; the plunger is gently lowered on the paste in the mould.  The settlement of plunger is noted. If the penetration is between 5 mm to 7 mm from the bottom of mould, the water added is correct, If not process is repeated with different percentages of water till the desired penetration is obtained. 4. Setting time  This test is used to detect the deterioration of cement due to storage. The test is performed to find out initial setting time and final setting time.  Cement mixed with water and cement paste is filled in the Vicat mould.  Square needle is attached to moving rod of vicat apparatus.  The needle is quickly released and it is allowed to penetrate the cement paste. In the beginning the needle penetrates completely. The procedure is repeated at regular intervals till the needle does not penetrate completely.(up to 5mm from bottom)  Initial setting time =