CEMENT Lecture Note.pptx

For Engineering Geology Student and Civil Engineering Student

1. Presentation On CEMENT Presented By: Mahendra Acharya Roll No: 14 Subject: Construction Material Engineering Level: Third Semester, M.Sc. E ngineering Geology Presented To: Associate Professor Dr. Naresh Kazi Tamrakar Central Department of Geology, Kirtipur Kathmandu Nepal M.Sc. Engineering Geology

2. Content of Presentation: Cement History and Historical Uses Types of Cement Portland Cement Production Process Ordinary Portland Cement Portland Pozzolana Cement Special Purpose Cement and Blended Cements.

3. 2. History of Cement and It’s Historical Use

4. History In Nepal

5. What is the average particle size of cement? a) 15 microns b) 45 microns c) 75 microns d) 100 microns Answer is (a ) Approximately 95% of cement particles are smaller than 45 microns and the average particle size is 15 microns.

6. Ordinary Portland Cement (OPC) This cement is obviously produced in the maximum quantity than other cements. It is produced by grinding Portland clinker with the possible addition of a small quantity of gypsum, water or both and not more than 1 % of air-entraining agents. This very useful types of cement. The clinker of Portland consists of calcium silicate and is obtained by heating to incipient fusion a predetermined and homogeneous mixture of materials mainly containing 59% – 64% lime ( CaO ) and 19% – 24% silica (SiO2) with 3% – 6% of alumina (Al2O3) and 1% – 4% iron oxide (Fe2O3). The setting and hardening of cement after the addition of water to it is due to the dissolution and reaction of the constituents. The calcium aluminate is the first to set and harden, then comes calcium trisilicate (3CaO.2SiO2.3H2O) which is responsible for the early gain in strength during the first 48 hours. Calcium disilicate reacts slowly and contributes to the strength at a later stage usually from 14 to 28 days.

7. OPC (Continue..) Typical chemical reactions are as follows: 3CaO.Al2O3 + 6H20 → 3CaO.Al2O3.6H2O (3CaO.SiO2) + 6H2O → 3 CaO.2SiO2.3H2O + 3Ca(OH)2 3 (2CaO.SiO2) + 6 H2O → 3CaO.2SiO2.3H2O + 3 Ca(OH)2 Types of Ordinary Portland cement 33 grade ordinary Portland cement, 43-grade ordinary portland cement, 53 grade ordinary Portland cement,

8. Meaning of Grade: 43 Ordinary Portland cement grade 43 Properties of ordinary Portland cement grade 43 are following:- 43 grade means the cement comprehensive strength after 28 days is about 43N/mm2. It is high strength Portland cement mostly used for different types of concrete RCC work and reinforcement work. Properties of ordinary Portland cement grade 43 following:- ● their fitness is about =225 Kg/m2 ● comprehensive strength after 3 days = 23 N/mm2 ● comprehensive strength after 7 days = 33 N/mm2 ● comprehensive strength after 28 days = 43 N/mm2

9. Ordinary Portland Cement Grade 53 53 Grade means comprehensive strength of cement after 28 days is about 53 N/mm2. It is high strength cement used in low quantity mostly used for Bridge formation ,concrete Railway sleeper construction ,high rise building ,RCC work , factory construction etc. Properties of ordinary Portland cement grade 53 are following:- ● their fitness is about =225 kg/m2 ● comprehensive strength after 3 days = 27 N/mm2 ● comprehensive strength after 7 days = 37 N/mm2 ● comprehensive strength after 28 days = 53 N/mm2

10. Rapid Hardening  Portland Cement The cement is manufactured by intimately mixing together calcareous and argillaceous and/or other silica, alumina or iron oxide bearing materials.   This cement has the same chemical composition as the ordinary Portland cement but is more finely ground. Its  24 hours strength is nearly equal to that attained by ordinary portland cement after 3 days.   The use of this cement permits early removal of shuttering thus directly affecting saving in time and money. It is generally used in road work and bridge construction where the time factor is very important.

11. Extra Rapid H ardening C ement : Extra rapid hardening cement is a proper modification of rapid hardening cement. It is manufacture by inter grinding Calcium Chloride with rapid hardening portland cement. Normally, calcium chloride with 2 percentage by weight of rapid hardening cement is mixed. Since Extra rapid hardening cement is very sensitive, concrete should be transported, placed, compacted, and finished within 20 minutes after mixing. After the addition of water, a very huge amount of heat is evolved within a short period of time along with hydration. So, this type of cement is perfect for concreting in cold weather. Properties of Extra Rapid hardening cement: At the age of one or two days strength of Extra rapid hardening cement is 25% more than rapid hardening cement, and only 0-20 % higher at 7 days but at 90 days both cement have nearly the same strength. The use of Extra rapid hardening cement in pre-stressed concrete is prohibited.

12. Sulphate Resisting Cement : Since ordinary Portland cement is susceptible to attack of sulfate, sulfate resisting Cement is developed to use where the soil is infected with sulfates. Due to the attack of S ulphate in O.P.C. cement, there are chances of expansion within the framework of concrete and there are cracks and subsequent disruption.

13. Sulphate Resisting Cement : Under the following conditions sulphate resisting cement is used: When concreting is done for Marine structure in the zone of tidal variations. Where foundation soil is infected with Sulphate. In marshy soil or sulphate bearing soil. Concrete construction used for sewerage treatment, etc.

14. Quick setting Cement: Quick setting cement sets very fast. This cement is used for aggressive foundation conditions like where pumping is needed or submersible land area. In quick setting cement, the quick setting property is achieved by reducing the Gypsum content at the time of clinker grinding. Quick setting cement is also used in some typical grouting operations.

15. What is the initial setting time of cement? a) 1 hour b) 30 minutes c) 15 minutes d) 30 hours Answer is (b)

16. Low Heat Cement Low Heat Cement is specially blended to provide a lower heat of hydration in concrete. This unique attribute makes it ideal for mass concrete pours where the rate of temperature rise and the maximum temperature achieved must be controlled in order to reduce the risk of thermal cracking. Benefits of Low Heat Cement Assists in minimizing the potential for thermal cracking in thick concrete sections Significantly improved later-age concrete strengths Improved durability performance Increased workability and pumpability with large pours.

17. Low Heat Cement Properties: Australian Standard test methods, at a NATA registered laboratory.

18. Portland Pozzolana  cement  Portland pozzolana cement is prepared either by grinding clinker and pozzolana or by blending  Portland cement  and fine pozzolana .  The proportion of pozzolana may vary between  10% to 25%  by weight of cement. PPC  cement is suitable for the following conditions: For  waterfront structure  or for  marine structure  as in  dams, bridge piers  and  thick foundation  where mass concrete is used, also used for  sanitation sys tem like  Sewers .

19. Advantages of PPC (Portland  Pozzolana  cement ) The production is economical because costly clinker is replaced by cheaper. This cement  reduces the permeability  so, suitable for hydraulic structure. But it requires very fast curing is tedious. It produces a very slow rate of the heat of hydration and also reduces the heat. The particle size of PPC is smaller than OPC, so it improves the  pore size distribution  and also reduces micro-cracks. PPC mortar is  more volume  than OPC mortar. The  Ultimate long term Strength  of PPC is more than OPC if enough curing for pozzolanic action.

20. High Alumina  C ement  This cement is obtained by grinding high alumina clinker consisting of  monocalcium aluminates .  High alumina cement clinker is obtained by complete or partial fusion of a predetermined mixture of materials mainly containing  alumina (Al203)  and  lime ( CaO )   with a smaller proportion of iron oxides,  silica  (Si02) and other oxides.     High early strength, the high heat of hydration and very high durability against chemical attack are the characteristics of high alumina cement. It is black in color. Its rapid hardening properties are due to a higher percentage of calcium aluminate in place of calcium silicate as found in ordinary Portland cement.   

21. Air-Entraining Cement: Air entraining cement is manufacture by adding an air-entraining agent in power or in liquid form with  OPC cement  clinker. There are other external materials added are  animal and vegetable fats ,  oil  and another  acid  with a certain wetting agent like  aluminum powder, hydrogen peroxide , etc. by introducing air-entraining agent frost resisting characteristics of hardened concrete is increased. Workability, segregation, and bleeding property of concrete is improved by using this cement.

22. Masonry cement Masonry cement is obtained by intergrading a mixture of Portland cement clinker with  inert materials (non- pozzolanic ) , such as  limestone . Conglomerates, dolomite, limestone and gypsum, and air-entraining plasticizer in suitable proportions. Masonry cement is slow hardening, has high workability and high water retentivity that makes it especially suitable for masonry work.

23. Expansive cement: Expansive cement is a type of cement that shows  no change in volume on drying . This type of cement also not shrink while hardening or after that. This type of cement has been developed by using an expansive agent and stabilizer. Generally, sulphoaluminated clinker is mixed with Portland cement with stabilizer. This cement is used for grouting anchor bolts or grouting  machine foundations, grouting  the  prestressed concrete ducts  where volume change is very sensitive for stability. Fig : Use of expansive cement mortar in grouting of anchor bolts.

24. Coloured Cement Coloured cement is made by adding colour carrying  pigment  with a Portland cement clinker. The dose of pigment is  5-10  percentage  of Portland cement. For achieving various colors, either white cement or grey Portland cement is used as a  base materia l. The white Portland cement is manufactured as same as OPC.

25. Hydrophobic cement  Hydrophobic cement is prepared from ordinary Portland cement clinker by adding certain  water repellent chemicals   during the grinding process.  A water repellent coating is formed over each particle of cement that prevents water or moisture from the air being absorbed by the cement.     This film is broken during the mixing of concrete and the normal hydration process takes place in the same manner as with the ordinary Portland cement.    This cement is ideal for storage for longer periods in extremely wet climatic conditions.  The hydrophobic agents can be oleic acid, stearic acid,  naphthenic acid, etc.  This cement is different from waterproofing cement.

26. Which cement is most commonly used in under water construction where pumping is involved A. Low heat cement B. Quick setting cement C. Rapid hardening cement D. None of these Answer is B

27. White Cement White cement is same as that of grey Portland cement but the only differ is in the colour and fineness. This colour of this cement is determined by its raw materials and the process of manufacture. In this article we study about manufacture, properties, uses and difference of white cement. Brightness Index: 87%

28. 3. Portland P ozzolana Cement Portland Pozzolana cement is integrated cement which is formed by synthesising OPC cement with pozzolanic materials in a certain proportion. It is commonly known as PPC cement. NOTE: Pozzolana is a volcanic powder found in Italy near Vesuvius. A  pozzolanic material can be a natural or artificial which contains silica and aluminous in a reactive form. This materials usually doesn’t posses any cementitious properties, but when it is mixed with water or moisture or lime to undergo reaction with calcium hydroxide to form compounds possessing cement properties. Types of pozzolana materials : 1. Artificial pozzolana Fly ash, silica fume, rice husk, blast furnace slag. 2. Natural pozzolana Burnt clay, pumicite , diatomaceous Earth.

29. Manufacture of Portland P ozzolana Cement The primary raw materials used for this cement manufacture  are limestone (CaCO2) and clay (SiO2,AI2,O3,Fe2O3). Rocks are loaded into trucks and transported to the crushers, where the crushed into fine particles. Fine particles of clay and limestone are fed into the air-swept ball mills in desired proportions as per requirement and mixed very well before it is sent to silos for storing. This mixture is then pre-heated upto 800-1000c where calcinations of CACO3 to CaO takes place. The pre heated mixture is then sent into kiln where the mixture is heated to 1450C in rotary Kiln. The modules formed from the burning process called clinker. The clinker is cooled by a rotary cooler. This clinker is now mixed with gypsum and pozzolana materials in the required proportion and thus the Portland Pozzolana Cement is obtained.

30. Properties of Portland Pozzolana Cement Initial setting time = 30 min (minimum) Final setting time = 600 min (maximum). At 3 days 13MPa  (minimum) At 7 days 22 MPa (minimum) At 28 days 33 MPa (minimum) Drying shrinkage should not be more than 0.15% Fineness should not be less than 300 m 2 /kg Initial strength of PPC is less but final strength is equal to the 28 days strength of OPC PPC has lower rate of development of strength than OPC

31. Uses of Portland Pozzolana Cement Used in hydraulic structures, marine structures, construction near the sea shore, dam construction etc. Used in pre-stressed and post-tensioned concrete members. Used in masonry mortars and plastering. As it gives better surface finish, it is used in decorative and art structures. Used in manufacture of precast sewage pipes. Used under harsh concreting conditions.

32. Advantages of Portland Pozzolana Cement I t is an eco-friendly cement as the material used in the manufacture are made of natural recycled waste. It is very fine cement hence very good when used for plastering works. Pozzolano consists of silica material which makes it cheap and hence reduces the cost of the cement making it economical to use. Pozzolana cement has very good resistance against sulphate attack hence is used in hydraulic structures, marine structures, construction near the sea shore, dam construction etc. PPC used in pre-stressed and post-tensioned concrete members. It reduces the carbon monoxide emission from the concrete making it environmental friendly. As the pozzolano materials are very fine, it can fill gaps between the reinforcement and aggregate , thus reducing the shrinkage, honeycomb formation and bleeding can be reduced, which in turn increases the strength and durability of concrete.

33. Disadvantages of Portland Pozzolana Cement The initial strength obtained is less, which effect the de-shuttering of supports early. As it contains more fine material, handing of concrete is difficult. When compared to the OPC setting time is less for PPC Reduction in alkanity reduces the resistance to corrosion of steel reinforcement As the strength of this concrete gains slowly, curing process is very important. Any error in this could cause durability problems.

34. OPC Cement: Background OPC cement is Ordinary Portland Cement and in general  concrete  construction when there is no exposure to sulfates in the soil or groundwater OPC is the most common cement which is used. For almost all structural work including all kinds of concrete construction, OPC is an ideal building material and is one of the most commonly and widely used types of cement in the whole world. The name as Portland cement is given in 1824 by Joseph Aspdin because it has similarity in color and quality as found in Portland stone which is a white-grey limestone on the island of Portland.

35. COMPONENTS OF ORDINARY PORTLAND CEMENT: (OPC CEMENT) The raw materials used in the manufacturing of OPC are; In the form of clays and shales,  Argillaceous  or Silicates of Alumina. In the form of limestone, chalk, and marl, Calcareous or Calcium carbonate which is a mixture of calcium carbonate and clay. In the proportion of about two parts of calcareous materials to one part of argillaceous materials, the ingredients are mixed and then in a dry state or mixed in wet state crushed and ground in ball mills. Then in a rotary kiln at a temperature between 1400 degrees C to 1500 degree C the dry powder or the wet slurry is burnt and the kiln is first cooled and the clinker is obtained. Then according to the class of product gypsum is added and it is ground to the requisite fineness.

36. MANUFACTURING OF OPC CEMENT: There are four steps in the manufacturing process of OPC cement as given below: Crushing and Grinding of Raw Material Mixing or Blending Heating Grinding. 1. CRUSHING AND GRINDING OF RAW MATERIAL: The raw materials are crushed and grinded into small suitable size particles in the first step of the manufacture of cement and there are three types of the manufacturing process; Dry Process Wet Process Semi Wet Process. Depending upon the type of manufacturing process, the crushing and grinding process varies and the raw materials are dried up before crushing for dry process.

37. MIXING OR BLENDING In this step with clay in the desired proportion, the grinded raw material like limestone is blended or mixed, and to get a homogeneous mix, it is mixed well by the help of compressed air. These mixes are stored in silos in the dry process and in the wet process slurry tanks are used and there is 35 to 40% water in slurry. HEATING: In the manufacture of OPC cement, heating is the main important step. In this step, with the help of conveyor belts, the product obtained from the mixing is passed into the Kiln. Firstly, to 550C the mix is preheated and all the moisture content is evaporated and clay is broken into silica, iron oxide, and aluminum oxide. Then the temperature is rise to 1500 degree Celsius where the oxides form silicate, ferrite, and aluminate.

38.  After storage , the strength of cement is _______ A. Increases B. Remain same C. Decreases D. None of these Answer is C

39. Continue……. Then the product is cooled down to 200C and in the kiln, the end product is obtained which is in the form of greenish-black or grey colored balls and called cement Clinkers . GRINDING: In the final step of grinding the cement clinkers and the required amount of gypsum is mixed and into very fine particles it is grinded. Then stored in the silos and later packed in cement bags.

40. TYPES OF ORDINARY PORTLAND CEMENT: (OPC) Based on the different codes of the different countries there are the following types of OPC; AS PER ASTM 150: (AMERICAN STANDARDS) Type I;  As common or general-purpose cement Portland cement is used. Type II;  This type gives less heat during hydration and provides moderate sulfate resistance. Type III;  This type has high early strength and this cement is ground finer. Type IV;  for its low heat of hydration this type is used. Type V;  Where sulfate resistance is important this type is used and for its high sulfate resistance this cement has a very low C3A composition.

41. AS PER EN 197 NORM: ( EUROPEAN NORM) CEM I;  This type of cement is up to 5% of minor additional constituents and comprising Portland cement. CEM II;  This type of Portland cement is up to 35% of other single constituents. CEM III;  The percentage of blast-furnace slag is higher in this type of cement. CEM IV;  Up to 55% of pozzolanic constituents and is a Portland cement. CEM V;  Blast-furnace slag or fly ash and pozzolana and is a Portland cement. AS PER CSA A3000-08: ( CANADIAN STANDARDS) GU;  General used cement. MS;  Moderate sulfate resistant cement. HE, HEL;  Cement with high early strength. LH, LHL;  Cement wit low heat.

42. Blended Cement: Blended cement can be defined as uniform mix of ordinary Portland cement (OPC) and blending materials such as silica fumes, fly ash, limestone and slag to enhance its properties for different uses. Blended cement can improve workability, strength, durability and chemical resistance of concrete. Characteristics of Blended Cement The enhanced properties that are obtained due to blending of cement with different materials are, Improved workability and pumpability . Reduced water demand Enhanced bleed control Lower drying shrinkage and creep Improved resistance to sulphate attack and chloride penetration Reduced potential for Alkali Aggregate Reaction

43. Types of Blended Cement The classification of blended cement is based in the type of blending material used in the cement. As per American Society for Testing and Materials (ASTM) specification, blended cement are classified in to 4 types, 1. Type IS (X), Portland-Slag Cement Blends containing up to 70% slag cement are used for general construction. 2. Type IP (X), Portland- Pozzolan Cement Used for general construction, this blend can contain up to 50% pozzolan . Fly ash is the most common pozzolan used in blended cement. 3. Type IL (X), Portland-Limestone Cement Relatively new to the U.S. market, portland -limestone cement contains between 5% and 15% percent interground limestone. 4. Type IT, Ternary Blended Cement Ternary cements are blends two complementary supplementary materials such as fly ash, slag cement or silica fume.

44. It provides a finer texture than OPC when mixed and placed. So it can be used for finishing and elevation works. Water consumption is less which makes it easy to work with and shape. The strength gained after 28 days is significantly stronger than OPC, in both compressive and flexural stress. The permeability of blended concrete is low, due to which the life of concrete is extended by reducing penetration of aggressive water run-off compounds such as sulfates and chlorides when compared to ordinary cement. Cracks occurred due to thermal stress by variation of temperature is reduced by the use of blended cement. Reduced problems realted to Alkali-Silica Reaction by using a mix of blended cement as either silica fume and slag, or silica fume and fly ash. Blending material used are industrial by products, the used of these industrial by product reduces the use of natural resources such as limestone, silica and clay. Advantages

45. Uses of Blended Cement Blended cement makes it an ideal choice for a wide range of applications such as, Domestic construction Major engineering project. Pre-cast concrete where high durability and off-form finish are required Stabilisation including pavement recycling for road construction Mining applications Specialist formulations such as adhesives, renders, mortars and grouts.

46. Special Purpose Cement: It is a specially blended cement, which provides a lower heat of hydration and superior sulfate, chloride and salt water resistance when compared to General Purpose cement. Special Purpose Cement may be used in marine applications, in mass concrete where reduced heat liberation is important or in aggressive sulfate-rich environments where increased resistance to salt attack is required. Where concrete is expected to be in contact with sulfates or other aggressive salts or solutions, analytical surveys must be completed and appropriate grade of concrete selected. As with General Purpose cements, the resistance to acid solutions is limited, but concrete life expectancy will be maximized by using Special Purpose Cement at high cement content and low water to cement ratio in fully compacted and cured concrete

47. PROPERTIES The performance of the cement when tested using Australian Standard test methods under standard conditions will typically be within these ranges. F actors that will influence the strength and durability of concrete containing Special Purpose Cement are: • Mix design, including admixtures • Temperature - ambient and materials • Air content • Compaction of concrete • Curing of concrete