Introduction to Cement - 3 (Kalpna Sharma) PDF

Raw Materials The major raw materials used in the manufacture of cement are rich in Calcium, Silicon, Iron and Aluminium. These minerals are used in different form as per the availability of the minerals.  CEMENT MANUFACTURING There are four stages in the manufacture of Portland Cement:  c...

Raw Materials The major raw materials used in the manufacture of cement are rich in Calcium, Silicon, Iron and Aluminium. These minerals are used in different form as per the availability of the minerals.  CEMENT MANUFACTURING There are four stages in the manufacture of Portland Cement:  crushing and grinding the raw materials,  blending the materials in the correct proportions  burning the prepared mix in a kiln and  grinding the burned product, known as “clinker,” together with optimum percent of gypsum (to control the setting time of the cement). STANDARDIZATION OF CEMENT  Product standardization- The process of setting generally uniform characteristics for a particular good or service  Standards- Standards are published documents that establish specifications and procedures designed to ensure the reliability of the materials, products, methods, and/or services people use every day  Quality- The working definition of 'quality' is the minimum level of performance required to fulfil a specification.  STANDARDIZATION OF CEMENT Why standardization- Standardization, by both national and international bodies, aims to facilitate the exchange of goods and services. These standards are a reference guide for all parties enabling them to define a required specification and to provide a quality standard against which the delivered item can be tested and controlled. Most of the countries, if not all, have national standardization bodies. Most countries, if not all, have national standardization bodies.  Bureau of Indian Standards- (BIS) is one of the regulatory agencies in India. BIS is the national standards body for the harmonious development of the activities of standardization, conformity assessment and quality assurance of goods, articles, processes, systems and services and for matters connected therewith or incidental thereto.  As per BIS, cement is one of the trade products for which BIS certification is mandatory. INDIAN STANDARD SPECIFICATION FOR VARIOUS CEMENTS SN BIS CEMENT TYPE PURPOSE OF SPECIFICATION UTILISATION 1 IS :16353-2015 Portland Cement Clinker For Cement preparation 2 IS :269-2015 Ordinary Portland Cement- 33G- General Purpose 33G,43G,53G,43-S & 53-S 43G- Precast concrete:M- 25 concrete mix design 53G- FOR Higher grade concrete mix design M-30 and above 43 & 53S – Railway Sleeper 3 IS :12600-1989 Low Heat Portland Cement Mass Concreting to reduce risk of thermal cracking 4 IS :8041-1990 Rapid Hardening Portland General Purpose and high Cement early strength requirements 5 IS :3466-1988 Masnory Cement For mortars and plastering purpose INDIAN STANDARD SPECIFICATION FOR S BIS VARIOUS CEMENT TYPE CEMENTS PURPOSE OF UTILISATION N SPECIFICATION 6 IS :6452-1989 High Alumina Cement For high early strength in cold climate (under sea water construction) 7 IS :6909-1990 Super Sulphated Cement For Sulphate Resisting applications 8 IS :8042-2015 White Portland Cement For Tile, Flooring Work 9 IS :8043-1991 Hydrophobic Portland For Use in High Humidity Cement 10 IS :8229-1986 Oil-Well Cement For use in Oil Well 11 IS :12330-1988 Sulphate Resisting For Sulphate Resisting Portland Cement applications 12 IS :16993-2018 Microfine Ordinary & For rock grouting, grouting Sulphate Resisting concrete structures and Portland Cement under ground construction for leak prevention INDIAN STANDARD SPECIFICATION FOR BLENDED CEMENTS SN BIS CEMENT TYPE PURPOSE OF SPECIFICATION UTILISATION 1 IS :1489 (PART 1)- Portland-Pozzolana Cement- General Purpose- 2015 Fly Ash Based hydraulic structures like dam 2 IS :1489 (PART 2)- Portland-Pozzolana Cement- General Purpose 2015 Calcined Clay Based 3 IS :455-2015 Portland-Slag Cement General Purpose 4 IS :16415-2015 Composite Cement General Purpose  Family of Portland Cement Sulph Hydropho Resist Oil Well bic White Rap Ordinary Portland Cement Harden Low Heat Clinker Supersulp C3S + C2S + C3A + C4AF + CaO + h Composite MgO H Alumina OPC PSC PPC Masonry  Indian Standard Specifications for SN IS No. Various Types of Cement Reaff. Yr. Amendments Title 1 IS 16353:2015 2020 - Specification for Portland cement clinker 2 IS 269:2015 2020 - Specification for ordinary Portland cement 3 IS 455:2015 2020 1 Specification for Portland slag cement 4 IS 1489 (Part 1):2015 2020 1 Specification for Portland Pozzolana cement: Part 1- Fly ash based 5 IS 1489 (Part 2):2015 2020 - Specification for Portland Pozzolana cement: Part 2- Calcined clay based 6 IS 3466:1988 2018 9 Specification for masonry cement 7 IS 6452:1989 2014 9 Specification for high alumina cement for structural use 8 IS 6909:1990 2021 5 Specification for super sulphated cement 9 IS 8041:1990 2014 4 Specification for rapid hardening Portland cement 10 IS 8042:2015 2020 - Specification for white Portland cement 11 IS 8043:1991 2014 3 Specification for hydrophobic Portland cement 12 IS 8229:1986 2018 6 Specification for oil-well cement 13 IS 12330:1988 2019 6 Specification for sulphate resisting Portland cement 14 IS 12600:1989 2014 5 Specification for low heat Portland cement 15 IS 16415:2015 2020 - Specification for composite cement 16 IS 16993:2018 - 1 Specification for composite cement  1. Portland Cement Clinker IS 16353: 2015 is for both chemical and mechanical characteristics Made by burning powdered raw mix at 1400-14500C in rotary kiln Consists of four major crystalline mineral phases alite, belite, aluminate, ferrite and minor compounds such as free lime, magnesium oxide, alkali oxides, heavy metal oxides, chlorides etc. In absence of gypsum (set regulator), clinker when finely ground, sets immediately on add water- a phenomenon called Flash set Chemical characteristics are to be tested with clinker only while mechanical characteristics are tested after cement preparation.  2. Ordinary Portland Cement IS 269: 2015 Most commonly used for construction work, available in three grades 33 Grade, 43 Grade and 53 Grade. Grading has been done as per the minimum compressive strength requirement at different ages These grades are introduced to cater the needs for the construction of long span bridges, high rise structures and other structures of gigantic magnitude requiring high grades of concrete Introduction of precast/ prestressed railway sleepers necessitated production of Special grade OPC aimed to obtain desired strength and rate of strength gain Thus two more varieties were added OPC 43 S and OPC 53 S Grade cement Five types of Portland Cement made in India which are differ from physical and chemical property especially compressive strength. The most important use of Portland cement is the production of concrete. It plays an important role in setting and hardening the concrete. It may be molded to obtain a hard and fire-proof material which may further be employed in designing buildings, shop floors, reservoirs and other foundations. Any structure that is meant to support huge amounts of weight will bring Portland cement into use. Due to its ability to prevent corrosion, it is also put to use in ships, tanks and bunkers.  Undisputed Advantages of Blended Cements Low heat of hydration Reduced water demand Improved resistance to sulphate and chloride Increased resistance to ASR Waste consuming Natural resource saver  3. Portland Slag Cement IS 455: 2015 Clinker + GGBFS + gypsum Slag 25-70 % by mass Fineness is kept above 225 m2/kg Prepared by inter grinding or separate grinding and blending Because of low lime content, sulphate resistance properties of concrete improve and make it suitable for coastal areas Heat of hydration is lower than OPC and PPC General purpose cement but particularly desirable for marine structures, sewers, mass concreting, large foundation etc.  4. & 5. Portland Pozzolana Cement IS 1489 (Part 1): 2015 Fly ash based IS 1489 (Part 2): 2015 Calcined Clay based Prepared by either inter grinding or separate grinding and blending Clinker + fly ash/ CCP + gypsum Pozzolana 15-35 % by mass, Calcined Clay-10 to 25% Fineness is kept above 300 m2/kg General purpose cement but more durable in aggressive environment Good resistance to sulphate attack, enhances impermeability and cohesiveness of concrete, low heat of hydration Mostly used for domestic consumption like plastering, brick work, mass concreting for dams, large foundations  6. Masonry Cement IS 3466:1988 Cement for working of mortars for bricks, stones and concrete block masonry Clinker + gypsum + pozzolana/inert fillers + air entraining agents Considered superior to lime mortar, lime-cement mortar or cement mortar Chances of misuse as a structural cement  7. High Alumina Cement IS 6452:1989 First published in 1972, first revision on 24.11.1989 (currently used) A special cement containing hydraulic calcium aluminates as the major ingredient Presence of monocalcium aluminate (CaO Al2O3- CA) imparts unique properties- high early strength and refractoriness Mainly a refractory cement In cold regions may be used as a structural material taking advantage of high heat of hydration and high early strength development As CA imparts high early strength hence HAC has special utility for emergency repair and construction Hydration product of CA conversion from dicalcium aluminate hydrate to aluminium hydroxide + tricalcium aluminate hydrate + water results in increased porosity and gradual reduction in strength The above conversion is more rapid in presence of moisture and temperature 18-200C In tropical climate the loss in strength can be 50 to 80%  7. High Alumina Cement Due to controversial results of long term storage effects on HAC concrete under water, at temperatures around 180C the use of this cement should be restricted to areas of continuously low temperatures and highest summer temperature may not exceed 180C The restrictions for use of HAC about use in concrete are:  HAC is not to be used in locations where temperatures can exceed 180C even for a short period  HAC shall not be used for mass concreting where high heat of hydration can induce conversion of hydrated compounds  Accelerators (e.g. calcium chloride) shall not be used with HAC  Steam curing/ elevated temperature curing shall be avoided  HAC shall not be mixed with any other type of cement  8. Super Sulphated Cement IS 6909:1990 First published in 1973 It contains 80-85% GGBFS, 10-15% calcium sulphate (gypsum or anhydrate) and 5% Portland Clinker or Lime as an activator. Important amendments include I. incorporating a clause on false set of cement II. permitting packaging of cement in 25 kg bags, III.making compulsory provision for issuing a certificate indicating the total chloride content in percent by mass of cement, IV.modification in the tolerance requirements for the mass of cement packed in bags, etc.  8. Super Sulphated Cement Super sulphated cement has been successfully used in a variety of aggressive conditions, for marine works, mass concrete jobs to resist the attack by aggressive water, reinforced concrete pipes in ground water, concrete construction in sulphate bearing soils, It has been used for the underside of bridges over railways and for concrete sewers carrying industrial effluents.  8. Super Sulphated Cement Its use under tropical conditions has' also been recommended, provided the prevailing temperature is below 40°C. Although its use as a general purpose cement can be made with adequate precautions, it is not recommended for producing steam- cured products. Production of this cement will also result in greater utilization of blast furnace slag, an industrial by-product of steel in the country. Note - The limit of 40°C for use of this cement in tropical conditions is on the basis of available literature and this limit will be reviewed when more experience will be gained with the use of this cement in this country.  9. Rapid Hardening Cement IS 8041: 1990 Portland cement designed to hydrate faster Used for special purpose when a faster rate of early high strength / rapid development of strength is required to carry out urgent repair etc. Applications are in air field and highway pavements, marine structures and bridge decks High C3S content combined with higher minimum fineness specified (more than 325 m2/ kg), contribute towards high early strength The rapid gain of strength is associated with high rate of heat evolution; hence, not used for mass construction One day and seven day strength specified  10. White Portland Cement IS 8042: 2015 Basically OPC except that while choosing raw materials, maximum iron oxide content is strictly restricted to 1% C4AF imparts grey color to cement High burning temperature Special quenching system is used Clinker is made using fuel oil/ gas as fuel to ensure whiteness and with iron oxide content below 0.4% to ensure whiteness Use of whiteners Application- decorative, for aesthetic value, in tiles and flooring  11. Hydrophobic Cement IS 8043: 1991 Hydrophobic cement consists of finely ground cement with a suitable hydrophobic agent like oleic acid, stearic acid or pentachloro phenol The hydrophobic agents coat the cement particles by a water repellent film and entrain about 1 percent air Thus cement is protected from moisture on prolonged storage under unfavorable conditions Protective film is destroyed during mixing in mortar or concrete They impart a high level of protection of cement against premature hydration from atmosphere  12. Oil Well Cement IS 8229: 1986 Made from clinker and special additives to prevent porosity Wide applications in the exploration for and the production of oil and gas ( to fill the space between the steel lining tubes and oil well walls) It sets slowly and is used as slurry to allow sufficient time to reach large depths in oil wells Organic retarders are used to prevent from fast setting Once it sets, gains strength rapidly and remains stable under high temperature and pressure conditions API specification 10A Nine classes of well cement for use at different well depths  13. Sulphate Resisting Cement IS 12330: 1988 C3A content is restricted to 5%, C3S is moderate and other chemical constituents are similar to OPC Used for construction of structures in contact with soil or water with high sulphate concentration Beneficial in the areas where concrete is exposed to seacoast or sea water or soil or ground water This cement can be used to reduce the impact of damage to harsh environment Cement to withstand the attack of souble sulphate salts in ground water (-300 ppm) or soil (-0.2 %)  14. Low Heat Cement IS 12600: 1989 High proportion of C2S, Low C3S and C3A contents Slow in hardening in early ages and heat liberated due to hydration is reduced Due to low C3S, minimum early strength is lower than OPC but ultimate strength is unaffected To ensure sufficient rate of strength gain, fineness is not less than 320 m2/kg Suitable for mass concreting such as dams, bridge abutments and retaining walls  15. Composite Cement IS 16415:2015 Composite Cements are the cements in which a proportion of Portland cement clinker is replaced by industrial by products, granulated blast furnace slag and pulverized fuel ash. Composite cement offers better opportunity to conserve natural resources in terms of limestone by replacing higher percentage of clinker, having lower carbon footprints without compromising on concrete properties. Material Proportion to be used in Composite Cement SN Material Proportion (Percent by weight) 1 Portland Cement Clinker/ OPC 35-65 2 Fly ash 15-35 3 Granulated slag 20-50  Indian Standard Specifications for Hydraulic Cements Requirements for Mechanical Characteristics as per Indian Standard Specifications for Hydraulic cements BISSpecificatio IS: IS: 1489 IS: 12600- IS: 8041- IS: 8042- IS: 8043- IS: 1489 (Pt IS: 455- IS: 12330- IS: 6909- IS: 16415- 16353- IS: 269- 2015 (pt II)- n→ 1989 1990 2015 1991 I)- 2015 2015 1988 1990 2015 2015 2015 Clinker PPC (FA PPC (CCP TestParameter↓ OPC 33 OPC 43 OPC 43 S OPC 53 OPC 53 S LHC [a] RHC WPC [b] HPC [c] PSC SRPC [d] SSC CC [ ] Based) Based) Fineness, m2/kg NS 225 225 370 225 370 320 325 225 350 300 300 225 225 400 300 (min.) Setting Time, min. Initial (min.) 30 30 30 120 30 120 60 30 30 30 30 30 30 30 30 30 Final (max.) 600 600 600 600 600 600 600 600 600 600 600 600 600 600 600 600 Compressive Strength N/ mm2 24 ± 1/2 h (min.) NS NS NS NS NS NS NS 16 NS NS NS NS NS NS NS NS 72 ± 1 h (min.) 16 16 23 23 27 27 10 27 16 16 16 16 16 10 15 23 168 ± 2 h (min.) 22 22 33 37.5 37 37.5 16 NS 22 22 22 22 22 16 22 33 672 ± 4 h (min./ 33 33/48 43/58 43 53 53 35 NS 33 30 33 33 33 33 30 43 max.) Soundness Le Chat Exp. 10 10 10 5[*] 10 5[*] 10 10 10 10 10 10 10 10 5[*] (cold) 10 mm (max.) [e] Autoclave Exp. 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 NS 0.8 % (max.) [f] DS ≤ 0.15 % DS ≤ 0.15 Slag & %& Slag Other Content ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ Pozzolana Pozzolan Content ─ DS ≤ 0.15 % Requirements 70 % Content 15- a Content 25-70 % (min.) 35 % 10-25 % [a]: Heat of Hydration, kJ/ kg (max.): 272 at 7 days and 314 at 28 days [e]: 5 mm (max.) after aeration [b]: Whiteness Index: > 70 % [f]: 0.6 % (max.) after aeration [c]: Hydrophobicity test is an additional requirement [*]: Without aeration [ ]: Clinker ground to fineness 220 ± 25 m2/ kg & gypsum added to get SO3 ≤ 3.5 for [d]: Max sulphate expansion at 14 days 0.045 % (optional) conformity check  Indian Standard Specifications for Hydraulic Cements Requirements for Chemical Characteristics as per Indian Standard Specifications for Hydraulic cements IS: IS: 1489 IS: 1489 IS: 16353- IS: 8041- IS: 8042- IS: 8043- IS: 455- IS: 12330- IS: 6909- IS: 16415- BISSpecification→ IS: 269- 2015 12600- (Pt I)- (pt II)- 2015 1990 2015 1991 2015 1988 1990 2015 1989 2015 2015 PPC (FA PPC (CCP TestParameter↓ Clinker OPC 33 OPC 43 OPC 43 S OPC 53 OPC 53 S LHC RHC WPC HPC PSC SRPC SSC CC Based) Based) Loss on Ignition % 1.50 5.00 5.00 4.00 4.00 4.00 5.00 5.00 7.00 5.00 5.00 5.00 5.00 5.00 NS 5.00 (max.) Insoluble Residue % 1.00 5.00 5.00 2.00 5.00 2.00 4.00 4.00 4.00 4.00 © © 4.00 4.00 4.00 © (max.) 2.5/ 3.0 Total SO3 % (max.) 2.70 3.50 3.50 3.30 3.50 3.30 2.5/ 3.0 3.50 3.50 3.50 3.50 3.50 2.50 6.00 3.50 Magnesium Oxide % 6.00 6.00 6.00 5.00 6.00 5.00 6.00 6.00 6.00 6.00 6.00 6.00 10.00 6.00 10.00 8.00 (max.) Lime Saturation 0.66-1.02 0.66-1.02 0.66-1.02 0.8-1.02 0.8-1.02 0.8-1.02 - 0.66-1.02 0.66-1.02 0.66-1.02 NS NS NS 0.66-1.02 NS NS Factor (range) Al2O3/ Fe2O3 (min.) 0.66 0.66 0.66 0.66 0.66 0.66 0.66 0.66 NS 0.66 NS NS NS NS NS NS Total Alkalies as 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 NS NS NS Na2O % (max.) 0.90* 0.90** Chloride % (max.) For prestressed 0.05 0.05 0.05 0.05 0.05 0.05 - 0.05 0.05 0.05 0.05 0.05 NS NS 0.05 concrete 0.10 For other uses 0.10 0.10 0.10 0.10 0.10 0.10 - 0.10 0.10 0.10 0.10 0.10 NS NS 0.10 Other Requirements Sulphid Sulphide Pozzolana Pozzolana e C4AF + Free Lime C3S 45 % C3S 45 % Fe2O3 1 Sulphur Content Content Sulphur 2C3A = 25 Clinker/ 3 % (max.) (min.) (min.) % (max.) 1.5 % 15 to 35 % 10 to 25 % 1.5 % % (max.) (max.) OPC-35 to (max.) 65 %, Fly ash- 15-35 C3S 35 % C3A 10 % C3A 9 % Slag 25 C3A 5 % Slag 70 % %, Slag- (min.) (max.) (max.) to 70 % (max.) (min.) 20 to 50 %, Sulphide C3A 3 to Sulphur 12 0.75 % C3S + C2S (max.) 70 % (min.) C3A= 2.65(Al2O3)-1.69(Fe2O3), C2S=2.87(SiO2)-0.75(C3S) When C3A ≤ 5% C3S= 4.07(CaO)-7.60(SiO2)-6.72(Al2O3)-1.43(Fe2O3)-2.85(SO3), When C3A > 5%