Unit 1.pdf

 CEIR11 Basics of Civil Engineering Dr. Lekshmi Mohan V Assistant Professor Department of Civil Engineering National Institute of Technology, Tiruchirappalli Email: [email protected] Course Objectives To give an overview of the fundame...

 CEIR11 Basics of Civil Engineering Dr. Lekshmi Mohan V Assistant Professor Department of Civil Engineering National Institute of Technology, Tiruchirappalli Email: [email protected] Course Objectives To give an overview of the fundamentals of the Civil Engineering fields to the students of all branches of Engineering To realize the importance of the Civil Engineering Profession in fulfilling societal needs 8/28/2024 CEIR11 Basics of Civil Engineering 3 Branches of Civil Engineering Structural Engineering Geotechnical Engineering Construction Engineering & Management Transportation Engineering Surveying Water Resources Engineering Environmental Engineering 8/28/2024 CEIR11 Basics of Civil Engineering 4 Structural Engineering Concerned with the structural design and structural analysis of buildings, bridges, towers, flyovers, tunnels, off shore structures like oil and gas fields in the sea, and other structures. Involves identifying the loads which act upon a structure and the forces and stresses which arise within that structure due to those loads, and then designing the structure to successfully support and resist those loads. Loads can be self weight of the structures, other dead load, live loads, moving (wheel) load, wind load, earthquake load, load from temperature change etc. 8/28/2024 CEIR11 Basics of Civil Engineering 5  Geotechnical Engineering Concerned with the rock and soil that civil engineering systems are supported by. Knowledge from the fields of geology, material science and testing, mechanics, and hydraulics are applied by geotechnical engineers to safely and economically design foundations, retaining walls, and similar structures. 8/28/2024 CEIR11 Basics of Civil Engineering 6 Construction Engineering Involves planning and execution of the designs from transportation, site development, hydraulic, environmental, structural and geotechnical engineers. As construction firms tend to have higher business risk than other types of civil engineering firms, many construction engineers tend to take on a role that is more business-like in nature: drafting and reviewing contracts, evaluating logistical operations, and closely monitoring prices of necessary supplies. 8/28/2024 CEIR11 Basics of Civil Engineering 7 Transportation Engineering Concerned with moving people and goods efficiently and safely Involves specifying, designing, constructing and maintaining transportation infrastructure which includes streets, canals, highways, rail systems, airports, ports, and mass transit. Includes areas such as transportation design, transportation planning, traffic engineering, some aspects of urban engineering, pavement engineering, Intelligent Transportation System (ITS), and infrastructure management. 8/28/2024 CEIR11 Basics of Civil Engineering 8 Surveying Surveying is the process by which a survey or measures certain dimensions that generally occur on the surface of the Earth. Surveying equipment, such as levels and theodolites, are used for accurate measurement of angular deviation, horizontal, vertical and slope distances. With computerisation, electronic distance measurement (EDM), total stations, GPS surveying and laser scanning have supplemented (and to a large extent supplanted) the traditional optical instruments. This information is crucial to convert the data into a graphical representation of the Earth's surface, in the form of a map. This information is then used by civil engineers, contractors and even realtors to design from, build on, and trade, respectively. 8/28/2024 CEIR11 Basics of Civil Engineering 9 Water Resources Engineering Combines hydrology, environmental science, meteorology, geology, conservation, and resource management. This area of civil engineering relates to the prediction and management of both the quality and the quantity of water in both underground (aquifers) and above ground (lakes, rivers, and streams) resources. 8/28/2024 CEIR11 Basics of Civil Engineering 10 Environmental Engineering Deals with the treatment of chemical, biological and/or thermal waste, the purification of water and air, and the remediation of contaminated sites, due to prior waste disposal or accidental contamination. Among the topics covered by environmental engineering are pollutant transport, water purification, waste water treatment, air pollution, solid waste treatment and hazardous waste management. 8/28/2024 CEIR11 Basics of Civil Engineering 11 Course Content Site selection for buildings - Component of building - Foundation- Shallow and deep foundations - Brick and stone masonry - Plastering - Lintels, beams and columns - Roofs. Surveying Importance – Principles – Types – Equipment - Types of Maps – Advanced Surveying Techniques Transportation: Modes of Transportation - Classification of Roads - Cross sectional Elements - Pavements - Traffic Parameters - Traffic Management Systems.. Sources of Water – Characteristics of water -- Water Supply-Quality of Water-Wastewater Treatment 8/28/2024 CEIR11 Basics of Civil Engineering 12 Course Outcome The students will gain knowledge on site selection, construction materials, components of buildings, roads and water resources A basic appreciation of multidisciplinary approach when involved in Civil Related Projects. 8/28/2024 CEIR11 Basics of Civil Engineering 13 Reference Books Punmia, B.C, Ashok Kumar Jain, Arun Kumar Jain, ‘Basic Civil Engineering’, Lakshmi Publishers, 2012. Satheesh Gopi, ‘Basic Civil Engineering’, Pearson Publishers, 2009. Rangwala, S.C, ‘Building materials’, Charotar Publishing House, Pvt. Limited, Edition 27, 2009. Palanichamy,M.S, ‘Basic Civil Engineering’, Tata Mc Graw Hill, 2000. Lecture notes prepared by Department of Civil Engineering, NITT. 8/28/2024 CEIR11 Basics of Civil Engineering 14 Lecture Objectives To introduce various building materials, stone and its classification 8/28/2024 CEIR11 Basics of Civil Engineering 15 BUILDING MATERIALS STONES BRICKS CEMENT CONCRETE STEEL CEIR11 Basics of Civil Engineering 16  STONES 9/5/2024 CEIR11 Basics of Civil Engineering 2 STONES Stone is a naturally available material of construction and is obtained from rocks. It is available in the form of rocks, which is cut to required size and shape and used as building block. Classification of Rocks Geological Classification Physical Classification Chemical Classification 9/5/2024 CEIR11 Basics of Civil Engineering 3 Geological classification Igneous rocks Sedimentary rocks Metamorphic rocks 9/5/2024 CEIR11 Basics of Civil Engineering 4 Igneous Rock Rocks that are formed by the cooling of molten rock material called magma Types Extrusive – fine-grained, glass appearance, used as construction aggregate, road base, decorative material and in concrete production (E.g., basalt) Intrusive – slow cooling, large crystals, coarse-grained and highly durable (used in structural elements, flooring, and paving, E.g., granite) 9/5/2024 CEIR11 Basics of Civil Engineering 5 Igneous Rock Based on the depth at which it crystallizes, classified into Plutonic rocks Volcanic rocks Hypabyssal rocks 9/5/2024 CEIR11 Basics of Civil Engineering 6  Plutonic Rock Intrusive-igneous rock Formed at greater depth below the earth surface Exposed on the surface by erosion of overlying sedimentary rocks with passage of time Coarsely crystallized Eg: Granites, syenites, gabbros Brihadeshwara Temple, Thanjavur 9/5/2024 CEIR11 Basics of Civil Engineering 7 Hypabyssal rocks Formed at shallow depths About 2-3 km below the surface of the earth Shows medium-grained crystals that are partly coarse and partly fine in size Eg: Dolerite Stonehenge, Britain 9/5/2024 CEIR11 Basics of Civil Engineering 8  Volcanic rocks Formed on the surface of the earth from lava coming out of the numerous volcanoes that erupt from time to time Constituent minerals are so small that they can be seen only after magnifying under microscope Eg: Basalt Kailash Temple, Elora Caves, Maharastra Panhala Fort, Maharashtra 9/5/2024 CEIR11 Basics of Civil Engineering 9 Sedimentary Rocks Formed by the deposition of products from weathering of pre-existing rocks. All the products of weathering are ultimately carried away from their place of origin by the agents of wind, rain, frost, etc. eg. Sandstone, Limestone, Gypsum, Gravel etc. Red Fort, Delhi Pyramids of Giza, Egypt 9/5/2024 CEIR11 Basics of Civil Engineering 10 Metamorphic Rocks When the pre-existing rocks (i.e. Igneous and Sedimentary rocks) are subject to great heat and pressure, they are changed in original form and composition eg. Slate, Marble, Gneisses Slate Marble Taj Mahal, New Delhi Gneiss 9/5/2024 CEIR11 Basics of Civil Engineering 11 Physical Classification Stratified Rocks These rocks possess planes of stratification and can easily be split up along these planes Eg: Sedimentary Rocks Unstratified Rocks These rocks do not exhibit any definite layers or strata Eg: Igneous rocks Foliated Rocks These rocks have a tendency to be split up in a definite direction only. Eg: Metamorphic Rocks 9/5/2024 CEIR11 Basics of Civil Engineering 12 Chemical Classification Siliceous Rocks In these rocks, Silica is the main constituent Hard and durable Eg: Granite, Quartzites etc. Argillaceous Rocks In these rocks, clay or argil is the main constituent Fine-grained, plastic and moldable Used in bricks and tiles Eg: Slates, Laterites etc. Calcareous Rocks In these rocks, calcium carbonate is the main constituent fine-grained to coarse-grained Eg: Lime stones, Marbles etc. 9/5/2024 CEIR11 Basics of Civil Engineering 13 Uses of Stones Stones are used as basic material for concrete, moorum of roads, calcareous cements etc. Stones are adopted to form paving of roads and foot paths. Stones are also used as ballast for railway track. Stone blocks are used in the construction of bridges, abutments, retaining wall, dams etc. 9/5/2024 CEIR11 Basics of Civil Engineering 14 Qualities of Good Building Stone A good building stone should have the following qualities: Stones must be decent in appearance and be of uniform colour Stones must be durable Must be acid resistant and free form any soluble matter Fracture should be sharp and clear It must have a wear less than 3 % It must have a specific gravity greater than 2.7 It must have a compact, fine, crystalline structure, and strong 9/5/2024 CEIR11 Basics of Civil Engineering 15 Lecture Objectives To introduce various tests on aggregates 9/5/2024 CEIR11 Basics of Civil Engineering 16 Aggregate Material used for mixing with cement, bitumen, lime, gypsum or other adhesive to form concrete or mortar The aggregate gives the finished product volume, stability, resistance to wear Commonly used aggregates include sand, crushed or broken stone, gravel (pebbles), broken blast- furnace slag, boiler ashes (clinkers), burned shale, and burned clay 9/5/2024 CEIR11 Basics of Civil Engineering 17 Applications Railway track Ballast Road Construction Retaining walls 9/5/2024 CEIR11 Basics of Civil Engineering 18 Tests for aggregates Following are the tests conducted on aggregates Impact test Crushing strength test Attrition test Hardness Test Water absorption test Freeze - thaw test Microscopic test Smith's test 9/5/2024 CEIR11 Basics of Civil Engineering 19 Aggregate impact test IS : 2386 (Part 4) Determines measure of resistance to sudden impact or shock Sieve the aggregate, pass through 12.5 mm and retain in 10 mm sieves (A) A metal hammer weighing 13.5 to 14.0 kg, lower end being cylindrical in shape, 50 mm long, 100.0 mm in diameter is allowed to fall from 380 mm height for 15 times. The crushed aggregate is removed from the cup and sieved on 2.36 mm IS sieve (B) 35% Weak for road surfacing 9/5/2024 CEIR11 Basics of Civil Engineering 20 Aggregate crushing value IS: 2386 (Part 4) – 1963. Gives a relative measure of resistance of an aggregate to crushing under a gradually applied compressive load A specimen of weight 3 kg (A) filled in cylinder and tested in a compression testing machine. The rate of loading is 4.0 N/mm2 per minute. The maximum load of 40 tonnes per minute is maintained and the load is released. Sample is then sieved through a 2.36 mm IS Sieve (B) Aggregate crushing value = (B/A) x 100% Not more than 25 % for wearing surfaces Not more than 45 % for non-wearing surfaces 9/5/2024 CEIR11 Basics of Civil Engineering 21 Attrition test To determine the resistance power of stone against the grinding action. In this test, some known weight (5kg) of stone pieces are taken and put in the Deval's attrition test cylinder. The cylinder is rotated about its horizontal axis for 5 hrs at the rate of 30 RPM.. Then the contents in the cylinder are sieved by 1.5 mm sieve. 𝑙𝑜𝑠𝑠 𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑤𝑒𝑎𝑟 = × 100 𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 9/5/2024 CEIR11 Basics of Civil Engineering 22 Los Angeles Abrasion test Determines hardness of aggregate The percentage wear due to relative rubbing action between the aggregate and steel balls (abrasive charge) Then the contents are sieved by 1.7 mm sieve. 𝑙𝑜𝑠𝑠 𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 𝐴𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 𝑎𝑏𝑟𝑎𝑠𝑖𝑜𝑛 𝑣𝑎𝑙𝑢𝑒 = × 100 𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 9/5/2024 CEIR11 Basics of Civil Engineering 23 Water absorption test Water absorption gives an idea on the internal structure of aggregate. Aggregates having more absorption are more porous in nature and are generally considered unsuitable, unless found to be acceptable based on strength, impact and hardness tests. IS 2386 (Part 3) About 2 kg (W1) of aggregate sample is taken, washed to remove fines and then placed in the Wire Mesh Bucket wire basket Immediately after immersion the entrapped air is removed from the sample by lifting the basket 25 mm above the base of the tank and allowing it to drop, 25 times at a rate of about one drop per second. The basket, with aggregate are kept completely immersed in water for a period of 24 ± 0.5 hour. The basket and aggregates are removed from water and dried with dry absorbent cloth and then oven dried (W2) 𝑊1 − 𝑊2 𝑊𝑎𝑡𝑒𝑟 𝑎𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 % = × 100 𝑊2 Percentage absorption of water should not exceed 0.6 9/5/2024 CEIR11 Basics of Civil Engineering 24 Freezing and thawing test Method covers the testing of coarse aggregates to determine their resistance to disintegration by repeated freezing and thawing in a sodium chloride solution. Helpful in judging the soundness of aggregates subject to freezing and thawing action Stone is placed in freezing mixture at 12°C for 24 hours and it is then warmed at atmospheric temperature. The procedure is repeated for several times and the behavior of stone is noted. 9/5/2024 CEIR11 Basics of Civil Engineering 25 Microscopic test Petrographic examination of the aggregate In this test, thin sections of stone are taken and they are examined in a microscope (pectographic stereo microscope) to study various properties like grain size, mineral constituents etc. Plane Polarized Light micrograph of alkali silica reaction (ASR) induced cracking of andesite aggregate. 9/5/2024 CEIR11 Basics of Civil Engineering 26 Smith’s test To find out the presence of soluble matter Clear water is taken and pieces of stones are placed in it. After an hour, water is vigorously stirred. If the water becomes dirty it indicates the stone contains earthy matter / loose particles. 9/5/2024 CEIR11 Basics of Civil Engineering 27  BRICKS 9/5/2024 CEIR11 Basics of Civil Engineering 28  Bricks Bricks are artificial blocks manufactured from tempered clay into standard sizes. History Sun-dried bricks - With the utilization of fire became burnt bricks In Mesopotamia, palaces and temples were built of stone and sun-dried bricks in 4000 B.C. Invention of kilns made mass production of bricks easy Romans made the first large-scale use of masonry arches and roof vaults in their basilica (domes), baths and aqueducts (arch bridge) Eagle aqueduct, Spain 9/5/2024 CEIR11 Basics of Civil Engineering 29 Chemical composition of brick Ingredients Concentration (%) Silica 50 – 60 Alumina 20 – 30 Iron oxide 5–6 Lime 1250 °C (more particularly, > 1300 °C) Liquid phase appears Promotes the reaction between belite and free lime to form alite (C3S) Cooling stage Molten phase (containing C3A and C4AF) gets transformed to a glass; if cooling is slow, C3A crystallizes out (causes setting problems), or alite converts to belite and free lime 9/5/2024 CEIR11 Basics of Civil Engineering 67 Inter-grinding Clinker with Gypsum (CaSO4) Final step in cement manufacture = (Clinker + Gypsum) Gypsum added as a set regulator (its absence causes flash set) Strict control on temperature is required Done in ball mills; vertical roller presses are now used for better efficiency Cement of required fineness produced by grinding 9/5/2024 CEIR11 Basics of Civil Engineering 68 Final compounds of Cement Bogue Compounds Sl. Compound Formula Abbreviation Range No. 1 Dicalcium silicate 2(CaO).SiO2 C2S 21 to 45% 2 Tricalcium silicate 3(CaO).SiO2 C3S 25 to 50% 3 Tricalcium Aluminate 3(CaO).Al2O3 C3A 5 to 11% 4 Tetra Calcium Aluminum Ferrite 4(CaO).Al2O3.Fe2O3 C4AF 9 to 14% 5 Other Constituents and Gypsum - - 8% 9/5/2024 CEIR11 Basics of Civil Engineering 69 Bogue Compounds C2S (Belite) C 3A It hydrates slowly. Starts hydrating after 7 It is fast reacting with large amount of days only heat generation It hardens more slowly Responsible for initial setting of cement Its contribution to initial strength is small Does not contribute to the gain of strength Gain of strength after 28 days is almost C3S (Alite) entirely due to C2S It hydrates more rapidly (70% hydration in C4AF 28 days) It is comparatively inactive Responsible for early strength of cement It has poor cementing value Less resistance to chemical attack It is slow in reaction with small heat generation Doesn't contribute to setting and hardening process. 9/5/2024 CEIR11 Basics of Civil Engineering 70 Rate of Heat Evolution During Hydration Stage I: Rapid evolution of heat, lasts about 15 minutes. Stage II: Dormant period, lasts until initial set occurs in 2 to 4 hours Stage III: Rapid reaction of C3S during the acceleration period, with the peak being reached at about 8-10 hours, much after final set at 4-8 hours and hardening has begun Stage IV: Rate of reaction slows down until steady state is reached in 12-24 hrs Stage V: Steady state 9/5/2024 CEIR11 Basics of Civil Engineering 71 Hydration of Cement: Formation of Calcium Silicate Hydrate (C-S-H) When water is added, C3A is the first compound to hydrate. Early setting of cement takes place due to C3 A C3A hydrates quickly, generates much heat and makes only small contributions to the strength within the first 24 hours Initial setting of cement is entirely due to C3A After C3A, hydration of C3S begins. It hydrates quickly and it attributes much to the early strength The strength gained during the first 7 days is mostly due to hydration of C3S Hydration of C2S takes place after 7 days only and may continue up to 1 year C3S and C2S contribute most to the eventual strength 9/5/2024 CEIR11 Basics of Civil Engineering 72  Different Types of Cement 9/5/2024 CEIR11 Basics of Civil Engineering 73 Different types of Cement 1. Ordinary Portland Cement 2. Rapid Hardening cement 3. Low Heat cement 4. Portland slag cement 5. Portland Sulphate resistant cement 6. Air entraining cement 7. White and coloured cement 8. High Alumina cement 9. Pozzolana cement 10. Oil well cement 11. Quick setting cement 12. Expanding cement 13. Hydrophobic cement 9/5/2024 CEIR11 Basics of Civil Engineering 74 Ordinary Portland Cement (OPC) It is also known as Normal setting cement It is used in road pavements, buildings, culverts, water pipes etc. Out of the total consumption of different types of cement 90% is OPC 9/5/2024 CEIR11 Basics of Civil Engineering 75 Rapid Hardening Cement It contains less quantity of C2S and more quantity of C3S It is generally used where high early strength is required It is used by concrete product manufacturers, highway pavements which are to be opened early for road traffic. 9/5/2024 CEIR11 Basics of Civil Engineering 76 Low Heat Portland Cement This cement is so called because it develops low heat at the time of hydration It contains C3A and C3S in less quantity because they develop early heat It develops strength quite late and it is generally used in massive concrete structures such as dams, bridge, abutments, retaining walls etc. 9/5/2024 CEIR11 Basics of Civil Engineering 77 Portland Slag Cement Also known as blended cement Percentage of blast furnace slag varies from 25 to 65% Slag is, essentially, a non-metallic product comprising of more than 90% glass with silicates and alumino-silicates of lime It is cheaper as compared to ordinary cement because waste product is used in it It can also be used in massive concrete such as dams, bridges, etc. 9/5/2024 CEIR11 Basics of Civil Engineering 78 Sulphate Resistant Portland Cement It contains very low percentage of C3A and C4AF It is used in canal lining, construction of sewer lines where acid formation is expected. 9/5/2024 CEIR11 Basics of Civil Engineering 79  Air Entraining Cement It is ordinary Portland cement mixed with small quantities of air entertaining materials during grinding The diameter of air bubbles varies from 0.075 mm and 1.25 mm. On account of air bubbles, the strength of cement is reduced Air bubbles are permitted only up to 3 to 4 %, as these reduce 10 to 15% strength of cement. This cement is more plastic and workable causing less segregation and bleeding in concrete It also reduces the water requirement High resistance to freeze-thaw 9/5/2024 CEIR11 Basics of Civil Engineering 80 White and Coloured Cement White chalk and China clay are used instead of lime stone and clay as these are having low percentage of Iron Oxide (i.e. 1 %) It is 3 to 4 times costlier than ordinary cement It is used for decorative floorings For coloured cement, suitable pigments varying from 5 to 10% free from soluble salts are added during grinding 9/5/2024 CEIR11 Basics of Civil Engineering 81  High Alumina Cement It contains 35% to 45% of aluminates, bauxite and chalk or lime stone and are mixed, dried and heated till they melt, and on cooling, they form clinkers It is dark in colour and initial setting time varies from 3 to 6 hours and final setting takes place within 2 hours of the initial set It gives high heat of hydration and, is also costlier than ordinary Portland cement It is used in structures subjected to the action of sea water, chemical and sulphate bearing water 9/5/2024 CEIR11 Basics of Civil Engineering 82 Pozzolana Cement Pozzolana is a naturally occurring material such as volcanic ash or Pumice stone or an artificial product such as burnt clay or shale containing siliceous and aluminous mineral substances As per BIS 1489-1967, the proportion of pozzolana material varies from 10 to 25% by weight of cement It increases the workability, and reduces heat of hydration It also offers greater resistance against sulphatic action and sea water. 9/5/2024 CEIR11 Basics of Civil Engineering 83  Oil Well Cement As the name indicates, it is used for cementing of oil wells It is used at greater depth, under high temperature and pressure Iron Oxide + alumina forms C4AF and proportion of C3A is very small, delays the setting of cement and also hardens quickly after setting It protects the oil well casing from corrosion 9/5/2024 CEIR11 Basics of Civil Engineering 84 Quick Setting Cement It has less proportion of CaSO4 (Gypsum) or a small amount of aluminum sulphate is added at the time of grinding Its initial setting time is 5 minutes and final setting time is 30 minutes Used in running water construction sites 9/5/2024 CEIR11 Basics of Civil Engineering 85 Expanding Cement Volume increases on hardening It takes about 15 days for the expansion to occur completely but the time can be controlled by curing The upper limit of expansion is 1% Uses to repair cracks 9/5/2024 CEIR11 Basics of Civil Engineering 86 Field Tests on Cement The colour of cement should be uniform gray with light greenish shade. Cement should feel smooth when touched. If hand is inserted in a bag of cement it should feel cool not warm. If a small quantity of cement is thrown in a bucket of water, it should sink and should not float on the surface. Cement should be free from any hard lumps. 9/5/2024 CEIR11 Basics of Civil Engineering 87 Fineness of Cement Fineness of cement affects hydration rate and hence the rate of strength gain The smaller the particle size, the greater the surface area-to-volume ratio, and thus, the more area available for water-cement interaction per unit volume Therefore, finer cement reacts faster with water The rate of development of strength and corresponding heat of hydration is high 9/5/2024 CEIR11 Basics of Civil Engineering 88 Fineness of Cement Fineness test is used to check the proper grinding of cement. The fineness of cement is measured as specific surface. Specific surface is expressed as the total surface area in square meters of all the cement particles in one kilogram of cement. The higher the specific surface is, the finer cement will be. Unit is m2/kg of cement 200 to 300 m2/kg of cement Minimum specific surface required for Ordinary Portland Cement - 2250 cm2/g Rapid Hardening Cement - 3250 cm2/g Portland Pozzolana Cement - 3000 cm2/g 9/5/2024 CEIR11 Basics of Civil Engineering 89  Tests for fineness 1. Blaine air permeability method IS:4031(Part-2):1996 The principle is based on the relationship between the rate of flow of air through a cement bed. 2. Standard sieve method IS:4031(Part-1):1996 9/5/2024 CEIR11 Basics of Civil Engineering 90  Tests on Cement 9/13/2024 CEIR11 Basics of Civil Engineering 3 Fineness of Cement by Blaine air permeability method Fineness: It is the degree of grinding of cement The rate of reaction depends upon the fineness of cement For accurate measurement, it is measured by surface area, air permeability method Normal value - 200 to 300 m2/kg of cement 9/13/2024 CEIR11 Basics of Civil Engineering 4 Fineness of Cement – by standard sieve method 100 gm of cement is weighed accurately, placed on IS: sieve No. 9 (90 micron) and sieved The residue left is weighed This shall not exceed 10% by weight of the sample This is estimated in terms of the specific surface, i.e., the surface area per unit weight 9/13/2024 CEIR11 Basics of Civil Engineering 5 Setting Time: Initial & Final Vicat’s apparatus Setting of cement is the phenomenon by virtue of which the green cement changes into hard mass The time between water is added in cement and initial setting takes place is known as Initial Setting Time Initial setting is a stage in the process of hardening after which any crack that may appear will not reunite and the completion of this process is, known as final setting time Cement should not loose its plasticity till the various operations of mixing, transporting and placing are For initial setting complete. Hence this time is generally kept not less than 30 minutes and the final setting is not more than 10 hours For final setting 9/13/2024 CEIR11 Basics of Civil Engineering 6 Compressive Strength The quality of concrete and cement is always judged by strength and that is only by compressive strength because cement is weak in tension and for it steel reinforcement is always provided For this purpose cement and standard sand are mixed in the ratio of 1:3 Grades of cement : 33, 43, 53 - (Strength (in MPa) on 28th day of curing) 9/13/2024 CEIR11 Basics of Civil Engineering 7 Soundness Free lime and magnesia present in cement makes the cement unsound by increasing the volume after setting. Expansion should not be more than 10 mm More lime (or calcium hydroxide) leads to cracks in concrete It is generally measured by Le-Chatelier method 9/13/2024 CEIR11 Basics of Civil Engineering 8  Concrete 9/13/2024 CEIR11 Basics of Civil Engineering 9 Concrete Concrete is the most versatile material for all types of construction works and has been used for innumerable construction works, either as plain concrete or as reinforced cement concrete or as precast concrete, or prestressed concrete or in many other forms. The various constituents of concrete are cement, water, fine aggregate, and coarse, aggregates. 9/13/2024 CEIR11 Basics of Civil Engineering 10 Role Aggregate: (Coarse and Fine) These are the inert or chemically inactive materials which form the bulk of cement concrete. These aggregates are bound together by means of cement. The aggregates are classified into two categories, Fine and coarse. The material which is passed through 4.75mm size sieve is termed as fine aggregate. Usually natural river sand, issued as a fine aggregate. The material which is retained on 4.75 mm size sieve termed as a coarse aggregate. Broken stone is generally used as a coarse aggregate. Water Water which is used for making concrete should be clean and free from harmful impurities such as oil, alkali, acid etc. In general water which is fit for drinking should be used for making concrete. 9/13/2024 CEIR11 Basics of Civil Engineering 11 Grades of Concrete Concrete as per IS 456:2000 is classified into three groups as ordinary concrete, Standard concrete and High strength concrete. M10, M15 and M20 are ordinary concrete M25, M30, M35, M40, M45, M50 and M55 are grouped as Standard concrete M60, M70, M75 and M80 are grouped under High strength concrete. The letter ‘M’ refers to the mix and the number indicates the specified compressive strength of that mix at 28 days expressed in or Mega Pascal (MPa) or N/mm2. M 5 - 1:5:10 (Cement : Fine aggregate : Coarse aggregate) M 7.5- 1:4:8 M 10 - 1:3:6 M 15 - 1:2:4 M 20 - 1:1.5:3 M 25 - 1:1:2 9/13/2024 CEIR11 Basics of Civil Engineering 12 Gain of strength with age The concrete develops strength with continued hydration. The rate of gain of strength is faster to start with and the rate gets reduced with age. It is customary to assume the 28 days strength as the full strength of concrete. The variation of strength with age is given below Age of curing (Days) Approx. Strength achieved 3 1/3rd of target strength 7 2/3rd 28 90 % 9/13/2024 CEIR11 Basics of Civil Engineering 13 Strength of Concrete Strength of concrete is its resistance to rupture. It may be measured in number of ways, such as strength in compression, in tension, in shear or in flexure. The compressive strength of concrete is generally determined by testing cubes or cylinders made in laboratory or field. The size of the mould should be 150 mm x 150 mm x 150 mm. Based on the compressive strength, the concrete is graded. The strength of the concrete is mainly depend on the following factors: Quality of materials and grading of the aggregates Water cement ratio Cement content Age of concrete and Methods of mixing, placing, compacting and curing. 9/13/2024 CEIR11 Basics of Civil Engineering 14 Workability of concrete The workability of concrete indicates the ease with which it can be mixed, placed and compacted. Slump test is the most commonly used method of measuring workability of concrete which can be employed either in the laboratory or at site of work. 9/13/2024 CEIR11 Basics of Civil Engineering 15 Water Cement Ratio The strength of concrete depends upon the quantity and quality of its ingredients i.e. cement, aggregate and water. General assumption is that strength of concrete directly depends up on the quantity of cement. If cement is more, strength will be more but this assumption is not correct because strength of concrete also depends upon water cement ratio. 9/13/2024 CEIR11 Basics of Civil Engineering 16 Operations in Concreting Storing of material (Cement, aggregate) Batching of material (By volume, by weight) Mixing of concrete (By hand, by machine) Transportation of concrete. Placing of concrete. Curing of concrete 9/13/2024 CEIR11 Basics of Civil Engineering 17 Storing of Material Cement: It is a fine powder and also hygroscopic in nature i.e. it absorbs moisture from air or free water and starts setting. Hence the warehouses constructed for its storage must fulfill the basic requirements. Cement stored for long time should be checked before its use. Aggregates: It is essential that aggregate should be free from deleterious materials, organic matters such as tree leaves, vegetable wastes, animal refuse etc. It should have uniform moisture content and proper grading of aggregates. 9/13/2024 CEIR11 Basics of Civil Engineering 18 Batching of Materials Batching means measurement of ingredients of concrete for proper mixing. Normally such a quantity is mixed in one batch, which can be transported, placed and compacted with in time i.e. before initial set takes place. Batching is of two types Volume Batching Weigh Batching Measurement of Cement: Cement is always measured by weight. A batch of concrete should always consume full number of bags. For this purpose weight, of cement bag is taken as 50 kg. Measurement of Water: Water is generally measured by volume. Measurement of Aggregate by Volume: For these purpose generally wooden boxes of capacity equivalent or part of one cement bag i.e. 35 liters are used. These boxes are known as Petties or Farmas or Gauge Box. 9/13/2024 CEIR11 Basics of Civil Engineering 19 Volume batching 9/13/2024 CEIR11 Basics of Civil Engineering 20 Transportation of concrete As the initial setting time of cement is generally 30 minutes, hence mixing, transportation, placing and compaction should be completed with in this time. In no case this time should not exceed one hour after initial setting time. 9/13/2024 CEIR11 Basics of Civil Engineering 21 Placing of Concrete As for as possible concrete should be placed in single thickness. In case of deep sections, concrete should be placed in successive horizontal layers and proper care should be taken to develop enough bond between successive layers. 9/13/2024 CEIR11 Basics of Civil Engineering 22  Curing of Concrete Concrete surfaces are kept wet for a certain period after placing the concrete. The period of curing depends on the type of cement and nature of work. For ordinary Portland cement, the curing period is 7 to 14 days. If rapid hardening cement is used, curing period can be considerably reduced. It can be done by spraying and ponding of water or covering the concrete with moist earth, sand, or wet gunny bags 9/13/2024 CEIR11 Basics of Civil Engineering 23 Steel Steel is probably the most versatile commonly used structural material. Steel is used to a large extent in modern multi- storied buildings. Steel is used as reinforcing bars/wires for concrete since concrete is weak in tension. Structural steel is available in various forms and shapes and it is being used for various structural components. 9/13/2024 CEIR11 Basics of Civil Engineering 24 How is steel manufactured? 2O 2 + 4 H 2 O + 4F e → 4 Fe (O H )2 4 Fe (O H )2 + O 2 + 2 H 2 O → 4Fe ( OH )3 Iron Ore Rolling/ other manufacturing (Fe2O3) Blast Furnace Molten material processes 9/13/2024 CEIR11 Basics of Civil Engineering 25 Steel Alloy of iron and carbon Steel is obtained by decreasing the carbon content by controlled oxidation. The excess oxygen is removed by incorporating manganese and silicon. When elements other than Mn and Si are present, it is called alloy steel. When certain elements, such as Cr and Ni are added, it is called stainless steel. 9/13/2024 CEIR11 Basics of Civil Engineering 26 Applications of Steel As Steel has high tensile strength, it was used in: Construction of buildings Infrastructure Tools Ships Automobiles Machines & appliances Weapons 9/13/2024 CEIR11 Basics of Civil Engineering 27 Different Types of Steels Based on Carbon Content: Low Carbon Steel 0% to 0.25 % of Carbon, Outstanding ductility and toughness. Good machinability and weldability, high formability, toughness, high ductility etc. Medium Carbon Steel From 0.25% to 0.55% C, Stronger than low – carbon steel but less tough than it, Railway wheels & tracks, gears etc. High Carbon Steel From 0.55% up to 2.1 % C, Hard, strongest, and least ductile compared to Low carbon steels. Knives, hack saw blades, chisels, hammers, drills, dies, machine tool cutters, punches, etc. 9/13/2024 CEIR11 Basics of Civil Engineering 28 Different Types of Steels Based on the Method of manufacture of Steels Bessemer steel Method The principle of Bessemer Converter is the removal of impurities from the iron by oxidation and the air is being blown through the molten iron. The furnace is made of steel with fire clay bricks to resist heat. The impurities manganese(Mn) and Silicon(Si) are converted into their respective oxides and that can be expelled out. Electric Arc Furnace Method It is an extremely hot enclosed region, where heat is produced employing electrodes for melting certain materials such as steel (scrap) without changing the electrochemical properties of the material(metal). The electric arc produced between the electrodes and the metal is used for melting the metal(scrap). 9/13/2024 CEIR11 Basics of Civil Engineering 29 Different Types of Steels Based on properties of some other types of Steels Shock-resisting Steel: These steels can resist fatigue loads and shock loads. High-strength Steel: Applied where Low weight and high strength are required. Tool Steel: These are mainly used for making Tools and Dies for cutting, forming and forging metals in their hot or cold conditions. Spring Steels: Used for making Coiled and Leaf springs. Heat Resistant Steels: These steels can resist corrosion, oxidation and creep at higher working temperatures. 9/13/2024 CEIR11 Basics of Civil Engineering 30 Different Types of Steels Based on Effect of Alloying elements on Steel Cobalt/Molybdenum: It has high servicing temperature or high temperature sustainability. Chromium: It improves Corrosion resistance and Abrasion resistance. Vanadium: It exhibits high temperature resistance, hardness and strength. Aluminum: It improves fracture toughness and acts as deoxidant. Phosporous: It increase strength, hardness and improves machinability. Sulphur: It improves machinability. Silicon: It exhibits high hardenability. Magnesium: It improves toughness and machinability. Manganese: Wear resistance and hardness is high. 9/13/2024 CEIR11 Basics of Civil Engineering 31