SRI LANKA STANDARD 1253 : 2003

UDC 666.942.7.

SPECIFICATION FOR

PORTLAND LIMESTONE CEMENT

SRI LANKA STANDARDS INSTITUTION

. SPECIFICATION FOR

PORTLAND LIMESTONE CEMENT

SLS 1253 : 2003

Gr. 17

SRI LANKA STANDARDS INSTITUTION 17, Victoria Place,

Elvitigala Mawatha, Colombo 08. SRI LANKA.

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SRI LANKA STANDARD SPECIFICATION FOR PORTLAND LIMESTONE CEMENT

FOREWORD This standard was approved by the Sectoral Committee on Building and Construction Materials and was authorized for adoption and publication as a Sri Lanka Standard by the Council of the Sri Lanka Standards Institution on 2003-12-19. Portland Limestone Cement (PLC) is a cement with many beneficial properties, but it is still a cement which is undergoing development and acceptance. Detailed information on its performance is not yet freely accessible, except for specialists in this field. Hence it was considered necessary, to provide access to current knowledge on PLC to the prospective Sri Lankan users. The Appendix H is included specially to satisfy this need. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test method or observation, shall be rounded off in accordance with CS 102. The number of significant places retained in the rounded off value shall be the same as that of the specified value in this standard. In the preparation of this standard the assistance derived from the publications of the International Organization for Standardization, American Society for Testing and Materials and the British Standards Institution is gratefully acknowledged. 1. SCOPE

This Sri Lanka standard for Portland limestone cement covers the requirements for composition, manufacture, chemical, physical and mechanical properties and for packaging and marking. This specification pertains to one strength class of Portland limestone cement. 2. REFERENCES CS 102 Presentation of numerical values SLS 107 Ordinary Portland Cement, Part 1 : Requirements, Part 2 : Test methods. SLS 428 Random sampling methods. ISO 565 Test sieves – Metal wire cloth, perforated metal plate electroformed sheet -

nominal sizes of openings. BS EN 196-6 Method of testing cement - Part 6 : Determination of fineness. BS EN 196-21 Method of testing cement-Part 21 : Determination of the chloride, carbon

dioxide and alkali content of cement BS EN 933-9 Tests for geometrical properties of aggregates - Part 9: Assessment of fines -Methylene blue test. EN 13639 Determination of total organic carbon content in limestone.

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3. DEFINITIONS For the purpose of this standard, the following definitions shall apply. 3.1 Portland limestone cement: A hydraulic cement consisting of two or more inorganic constituents (at least one of which is limestone) which separately or in combination contribute to the improvement of the properties of the cement, (made with or without other constituents, by inter grinding or other blending) 3.2 main constituent : Specially selected inorganic material in a proportion not less than 95 per cent by mass related to the sum of all main and minor additional constituents (see 5.1) 3.3 manufacturer : The establishment responsible for the quality of cement packed under the brand name of that establishment and shall include any of the following categories :

i) Cement manufactured and packed in Sri Lanka; ii) Cement imported in bulk form and packed in Sri Lanka ; and iii) Cement imported in any other form under a Sri Lankan brand name.

3.4 minor additional constituent : Specially selected inorganic material (except limestone) used in a proportion not exceeding a total of 5 per cent by mass related to the sum of all main and minor additional constituents (see 5.2) 3.5 reactive calcium oxide (CaO) : That fraction of the calcium oxide which under normal hardening conditions can form calcium silicate hydrates or calcium aluminate hydrates

NOTE : To evaluate this fraction the total calcium oxide content (See Figure 1) is reduced by the fraction corresponding to calcium carbonate (CaCO3), based on the measured carbon dioxide (CO2) content (See Appendix A) and the fraction corresponding to calcium sulphate (CaSO4), based on the sulphate (SO3) content measured relative to SO3 content. (see SLS 107 : Part 2 : 2002) after subtraction of the SO3 taken up by alkalis.

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NOTE

If the insoluble residue (Test method SLS-107) is less than 1.5 percent, the determination of the main constituents by SLS 107 method shall apply, without fusion.

FIGURE 1 - Analysis of the main constituents

Fusion of 1g sample with Na2CO3. See B.4.1

Precipitation by double evaporation by HCl. See B.4.2

Insoluble SiO2 See B.4.3

Volatilization of pure SiO2 by HF + H2SO4 See B.4.4

Small amount of R2O3 See Note B.4.4

Filtrate

R2O3 SLS-107 method

CaO SLS 107 method

CaO + MgO SLS 107 method

Filtrate

MgO By difference

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4. COMPOSITION AND MANUFACTURE

4.1 Portland limestone cement consists of an intimate and uniform blend of ordinary Portland cement and limestone, and it is produced either by inter grinding Portland cement clinker, or by blending ordinary Portland cement and finely ground limestone. The constituents of the above mineral additions are shown in Table 1. TABLE 1 –The composition of Portland limestone cement

5. CONSTITUENTS

5.1 Main constituents

5.1.1 Portland cement clinker

Portland cement clinker is made by sintering a precisely specified mixture of raw materials (raw meal, paste or slurry) containing elements, usually expressed as oxides, CaO, SiO2 Al2O3 Fe2O3 and small quantities of other materials. The raw meal, paste or slurry is finely divided, intimately mixed and therefore homogeneous. Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates (3CaO . SiO2 and 2CaO. SiO2), the remainder consisting of aluminium and iron containing clinker phases and other compounds. The ratio by mass (CaO) / (SiO2) shall be not less than 2.0. The content of magnesium oxide (MgO) shall not exceed 5.0 per cent by mass. 5.1.2 Limestone Limestone shall meet the following requirements: The calcium carbonate (CaCO3) content calculated from the calcium oxide content in accordance with 5.6 of SLS 107 : Part 2 : 2002 shall be at least 75 per cent by mass The clay content, when determined by the methylene blue test in accordance with test method given in Appendix F, shall not exceed 1.20 g/100 g. For this test the limestone shall be ground to a fineness of approximately 5 000 cm2/g determined as specific surface in accordance with BSEN 196-6. The total organic carbon (TOC) content, when tested in accordance with the test method given in Appendix G shall not exceed 0.20 per cent by mass.

Main constituentsClinker Limestone

85 to 94 6 to 15 0 to 5

Composition (percentage by mass)product designation

Portland limestone Cement

Minor additional constituents

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5.2 Minor additional constituents

Minor additional constituents are specially selected, inorganic natural mineral materials or inorganic mineral materials derived from the clinker production process excluding those constituents as specified under 5.1. Minor additional constituents, after appropriate preparation and on account of their particle size distribution, improve the physical properties of the cement (such as workability or water retention). They can be inert or have slightly hydraulic, latent hydraulic or Pozzolanic properties. However, no requirements are set for them in this respect. Minor additional constituents shall be correctly prepared, i.e selected homogenized, dried and comminuted depending on their state of production or delivery. They shall not increase the water demand of the cement appreciably, impair the resistance of the concrete or mortar to deterioration in any way or reduce the corrosion protection of the reinforcement. NOTE

Information on the minor additional constituents in the cement should be available from the manufacturer on request. 5.3 Calcium sulphate

Calcium sulphate is added to the other constituents of cement during its manufacture to control setting. Calcium sulphate can be gypsum (calcium sulphate dihydrate, CaSO4. 2H2O), hemihydrate (CaSO4 1/2 H2O), or anhydrite (anhydrous calcium sulphate, CaSO4) or any mixture of them. Gypsum and anhydrite are found naturally. Calcium sulphate is also available as a by-product of certain industrial processes. 5.4 Additives

Additives for the purpose of this standard are constituents not covered under 5.1 to 5.3, which are added to improve the manufacture or the properties of the cement. The total quantity of additives shall not exceed 1.0 per cent by mass of the cement (except for pigments). The quantity of organic additives on a dry basis shall not exceed 0.5 per cent by mass of the cement. These additives shall not promote corrosion of the reinforcement or impair the properties of the cement or of the concrete or mortar made from the cement. Admixtures for concrete, mortar or grouts in dry form shall not be incorporated in Portland limestone cement conforming to this standard.

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6. MECHANICAL , PHYSICAL AND CHEMICAL REQUIREMENTS 6.1 Mechanical requirements 6.1.1 Compressive strength The average compressive strength of three mortar cubes prepared ,stored and tested as in the method described in 6.0 of SLS 107 : Part 2 : 2002 shall not be less than 20.0 N/mm2 at 3 days and 40.0 N/mm2 at 28 days. The compressive strength of mortar cubes at 28 days shall be higher than that at 3 days and shall not exceed 62.5 N/mm2. 6.2 Physical requirements 6.2.1 Setting time The setting time of cement paste of standard consistency as determined by the method described in SLS107 : Part 2 : 2002 shall be :

a) Initial setting time not less than 45 min; and b) Final setting time not more than 10 h.

6.2.2 Soundness 6.2.2.1 The test method for soundness depends on magnesia content of the cement. Hence prior to testing for soundness, magnesia content shall be determined in accordance with Figure 1. For cement with magnesia content not more than 3 per cent 6.2.2.2 shall apply. For other cement 6.2.2.3 shall apply. 6.2.2.2 The cement shall not have an expansion of more than 10 mm when tested for soundness by the method described in 9 and 10 of SLS 107 : Part 2 : 2002 for cement. If the cement fails to comply with this requirement, a further test shall be made in the manner described. For this test, another portion of the same sample shall be used after it has been aerated by being spread out to a depth of 70 mm to 80 mm at a relative humidity of 50 per cent to 80 per cent for a total period of 7 days. The expansion of this aerated sub sample shall not exceed 5 mm. 6.2.2.3 The cement shall be tested for soundness by the autoclave test described in 10 of SLS 107 : Part 2 : 2002 and shall not have an expansion of more than 0.8 per cent. 6.2.3 Fineness Cement shall be tested for fineness by the method described in BS EN 196-6 :1992 and shall have specific surface of not less than 3 300 cm2/g. 6.3 Chemical requirements The properties of the Portland limestone cement shall conform to the requirements listed in Table 2 when tested in accordance with SLS 107 : Part 2 : 2002

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6.4 Loss on ignition

The loss on ignition as determined by the method described 5.3 of SLS 107 : Part 2 : 2002 shall not exceed 7.5 per cent (m/m). TABLE 2 - Chemical requirements

Property Requirements - percentage by mass of the final cement

Sulphate content (as SO3) � 3.5

Chloride content � 0.10

7 MARKING 7.1 Limestone Portland Cement manufactured in compliance with this standard shall be marked in relation to the product (either on the bag or, when supplied in bulk, on the manufacturer’s certificate, the delivery note or the invoice) legibly and indelibly with the following particulars:

a) name, address, trade mark or other means of identification of the manufacturer (see 3.3)

b) type of cement, that is : Portland limestone cement c) country in which cement is produced;

d) the net mass of the contents in kg; and e) the date of packing.

NOTE

1) Item b) shall appear in Sinhala, Tamil and English as specified in 7.1.(b)

2) Attention is drawn to the certification marking facilities offered by the Sri Lanka Standards Institution. See the inside back cover of this standard. 8. DELIVERY AND PACKAGING

The cement shall be supplied in bulk, or packed in bags of sufficient strength and construction to prevent damage or deterioration of cement, during normal handling. Any container used for bulk supply shall have an airtight fully enclosed body robust enough to prevent spillage of cement, and a special facility for dustless discharge such as air slide, pneumatic discharger or spiral conveyor. In order to assess whether cement bags are of sufficient strength, the drop test on bags consisting of Portland Limestone cement, as delivered, shall be carried out as described in Clause 11 of SLS 107 : Part 2 : 2002. Each Portland limestone cement bag shall be capable of sustaining 10 drops without failure to pass the test. When Portland Limestone cement is issued in bag form, the net mass of each bag shall be at least 50.0 kg. The net mass of the bag of cement shall be determined from its gross mass and the mass of package. The nominal mass of the empty bag shall be marked (to the nearest gram) on the package, where facilities exist for such marking. If mass of an empty bag is not

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displayed on the bag, mass should be determined by weighing 10 empty bags used for the same batch. These empty bags should be supplied by the manufacturer (See 3.3). The bags of Portland Limestone cement not in good condition, due to causes such as moisture patches, torn bags, burst stitches, spilling cement or exudation of cement dust shall be rejected. NOTE : To protect cement from premature hydration after delivery, bulk silos should be waterproof and internal condensation should be minimized. Paper bags should be stored clear of the ground, not more than eight bags high and protected by a waterproof structure. As significant strength losses begin after 4 weeks to 6 weeks of storage in bags in normal conditions, and considerably sooner under adverse weather conditions or high humidity, deliveries should be controlled and used in order of receipt. 9. MANUFACTURER’S CERTIFICATE The manufacturer shall be satisfied that the cement at the time of its delivery complies with the requirements of this standard (see Note 1). The manufacturer on request shall forward a certificate to this effect to the purchaser or his representative. The certificate shall include the following details in respect of the cement delivered (see Note 2). a) The percentage of clinker, limestone and minor additional constituents. b) The results of tests on:

i) Compressive strength at 3 days and 28 days; ii) Initial setting time; iii) Soundness; iv) Sulphate content; v) Chloride content; vi) Clay content of limestone; and vii) Calcium carbonate content of limestone.

NOTES 1. In case of imported cement time of delivery means the time of delivery to a Port in Sri Lanka. 2. If the time between the sampling and the delivery of bagged cement to a Port in Sri Lanka exceeds two weeks, the compressive strength of the cement (at 3 days and 28 days) may be reduced during transport and / or storage. In case of doubt cement should be re tested at the time of delivery. 3. If so requested by the purchaser, the manufacturer shall provide their auto control data relating to the cement supplier.

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10. INDEPENDENT TESTS 10.1 If the purchaser or his representative requires independent tests, they shall be carried out in accordance with this standard on the written instructions of the purchaser or his representative. 10.2 The manufacturer/vendor shall supply, free of charge, the cement required for testing. Unless otherwise specified in the enquiry and order, the cost of the tests shall be born as follows:

a) By the manufacturer/vendor if the results show that the cement does not comply with the requirements of this standard; and b) By the purchaser if the results show that the cement complies with the requirements of this standard.

NOTE : List of testing authorities outside Sri Lanka acceptable to the Sri Lanka Standard Institution is available on request. 11. SAMPLING AND ACCEPTANCE The criteria of acceptance shall be as agreed to between the manufacturer/the supplier and the buyer. If such an agreement is not possible or for the purpose of conforming with this standard, sampling of cement and criteria of conformity shall be in accordance with Appendix E. Appendix E also provides guidance on sampling of cement.

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APPENDIX A

DETERMINATION OF CARBON DIOXIDE CONTENT A.1 Principle The cement sample is treated with phosphoric acid to decompose the carbonate present. The carbon dioxide liberated is entrained in a current of carbon dioxide-free gas or air through a series of absorption tubes. The first two removes hydrogen sulphide and water and the following then absorb carbon dioxide. Two absorption tubes, each containing a granular absorption for carbon dioxide and anhydrous magnesium perchlorate to retain the water formed during the absorption reaction are weighed to determine the mass of carbon dioxide released.

A.2 Reagents

A.2.1 Copper sulphate (CuSO 4.5H2O)

A.2.2 Copper sulphate solution, saturated

A.2.3 Absorbent for hydrogen sulphide

Place a weighed quantity of dried pumice stone with a grain size between 1.2 mm and 2.4 mm into a flat dish and cover with a volume of saturated copper sulphate solution so that the mass of the copper sulphate solution is approximately half that of the pumice stone. Evaporate the mixture to dryness, while stirring frequently with a glass rod. Dry the contents of the dish for at least 5 h in an oven at a temperature of 155 ± 5 oC. Allow the solid mixture to cool in a desiccator and store in an airtight bottle.

A.2.4 Absorbent for water, anhydrous magnesium perchlorate Mg(Cl O4)2 with a particle size between 0.6 mm and 1.2 mm.

A.2.5 Absorbent for carbon dioxide, synthetic silicates with a particle size between 0.6 mm to 1.2 mm impregnated with sodium hydroxide (NaOH).

A.2.6 Concentrated phosphoric acid (H3PO4)

A.2.7 Concentrated sulphuric acid (H2SO4)

A.3 Apparatus

A.3.1 Figure 2 shows a typical piece of apparatus which can be fitted with either a cylindrical pressure container, a small electrical compressor or a suitable suction pump which will ensure an even flow of gas or air. The gas (air or nitrogen) entering the apparatus should have previously had its carbon dioxide removed by first being passed through an absorbent tube or tower containing the carbon dioxide absorbent (A.2.5). The apparatus consist of a 100 ml reaction flask (A) fitted with a three-neck adaptor. Neck B1 is connected to a dropping funnel (O), neck B2 to a connecting tube and neck C to a water cooled condenser. The funnel on to B1 and the connecting tube onto B2 are joined together by means of a Y-piece (P), so that the carbon dioxide-free air can flow either through the connecting tube or the funnel by means of a Mohr clip (N). After the condenser (L), the gas is passed through concentrated sulphuric acid (D), then through absorption tubes containing the absorbent for hydrogen sulphide (A.2.3) (E) for water (A.2.4)

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(F) and subsequently through two absorption tubes (G,H) which can be weighed and which are three-quarters filled with the absorbent for carbon dioxide (A.2.5) and a quarter with the absorbent for water (A.2.4). The absorbent for carbon dioxide (A.2.5) is placed upstream of the absorbent for water (A.2.4) with respect to the gas flow. Absorption tube (H) is followed by an additional absorption tube (I), which also contains the absorbent for carbon dioxide and water, which is fitted in order to protect absorption tube (H) against penetration by carbon dioxide and water from the air.

The absorption tubes (G) and (H) which are to be weighed may have, for example, the following sizes.

External distance between branches 45mm, internal diameter 20 mm. ,distance between the lower part of the tube and the upper part of the ground section 75mm, and tube wall thickness 1.5mm. A.3.2 Balance, capable of weighing to the nearest 0.0001 g. A.3.3 Electric oven, which can be set at 105 ± 5 oC and at 155 ± 5 oC. A.3.4 Desiccator, containing anhydrous magnesium perchlorate Mg(ClO4)2.

A.4 Procedure

Weight 1 ± 0.05 g of cement and place it in a dry 100 ml distillation flask. Connect the flask to the apparatus (A.3.1) as shown in Figure 2, but without the two absorption tubes (G) and (H). Pass a current of carbon dioxide-free gas through the apparatus for 15 min at approximately 3 bubbles per second (bubble counter) via the connecting tube onto B2 (branch onto B1, Mohr clip closed). Release the Mohr clip and remove the gas supply from the funnel (O). Add 30 ml concentrated phosphoric acid into the dropping funnel and reconnected the gas supply to fill the funnel (O).

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Condition the closed absorption tubes (G) and (H) for 15 min in the balance case in order to achieve temperature equilibrium. Then weigh each tube separately. Shut off the flow of gas and attach the tubes to the apparatus as shown in Figure 2.

Wear protective gloves when carrying out this operation.

Then reopen the gas flow. After 10 min close absorption tubes (G) and (H), remove them, place them in the balance case for 15 min and then weigh them separately. Repeat the passage of gas, removal and weighing of absorption tubes (G) and (H) for as long as is required for the results of two successive weighing of a tube not to differ by more than 0.0005 g.

If the change in mass of the absorption tubes (G) and (H) remains greater then 0.0005 g, renew the absorbents in tubes (E) and (F).

Attach the weighed absorption tubes (G) and (H) to the apparatus, as shown in Figure 2.

Open the funnel tap and allow the phosphoric acid to drop into the distillation flask (A). After the reaction has ceased, heat the contents of the flask to boiling and boil gently for 5 min. Maintain the gas flow through the apparatus until the flask has cooled to room temperature.

Close absorption tubes (G) and (H), remove them and place then in the balance case for 15 min and then weigh them separately. The increase in mass of each tube is used for the calculation of the carbon dioxide content (A.5).

The carbon dioxide is practically completely absorbed by tube (G). If the increase in mass of tube (H) exceeds 0.0005 g, renew the absorbent in tube (G) and start the test again.

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A.5 Expression of results Calculate the carbon dioxide content (in percent) of the cement from the formula: CO2 = m2 + m3 X 100 m1 Where m1 is the mass of cement test portion; m2 is the increase in mass of tube G after absorption; m3 is the increase in mass of tube H after absorption. The mean of the two results shall be rounded to the nearest 0.01 percent If the carbon dioxide content calculated from equation is less than 0.5 percent, repeat the determination with a cement sample weighing 2g.

A.6 Repeatability and reproducibility

The standard deviation of repeatability is 0.07 per cent

The standard deviation of reproducibility is 0.10 per cent

APPENDIX B

DETERMINATION OF TOTAL SILICA (SiO2)

B.1 Principle of the test This test method is based on the sodium carbonate fusion followed by double evaporation to dryness of the hydrochloric acid solution of the fusion product to convert silicon dioxide (SiO2) to the insoluble form. The solution is filtered and the insoluble siliceous residue is ignited and weighed. Silicon dioxide is volatilized by hydrofluoric acid and the loss of mass is reported as pure SiO2. B.2 Reagents Use only reagents analytical grade and distilled water, or water of equal purity.

B.2.1 Sodium carbonate (Na2CO3)

B.2.2 Hydrochloric acid (Specific gravity 1.19)

B.2.3 Hydrochloric acid (1 + 1)

B.2.4 Hydrochloric acid (1 + 3)

B.2.5 Hydrochloric acid (1 + 99)

B.2.6 Sulphuric acid ( 1 + 1)

B.2.7 Hydrofluoric acid (HF) B.3 Apparatus

B.3.1 Balance, capable of weighing to an accuracy of 0.0001 g. or better.

B.3.2 Desiccators, containing a drying agent example silica gel.

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B.3.3 Covered Platinum crucible.

B.3.4 300 ml casserole

B.3.5 Steam bath

B.4 Procedure B.4.1 Weigh a quantity of the ignited sample equivalent to 0.5 of the as-received sample calculated as follows:

M = [0.5 (100.00 - l ) ]/100 Where, M = mass of ignited sample, gram and

l = loss of ignition , per cent The ignited material from the loss on ignition determination (the method given in SLS 107: Part 2 : 2002 for content may be followed) may be used for the sample. Thoroughly mix the sample with 4 g. to 6 g. of Na2CO3 by grinding in an agate mortar. Place a thin layer of Na2CO3 on the bottom of the platinum crucible of 20 ml to 30 ml capacity add the cement - Na2CO3 mixture and cover the mixture with a thin layer of Na2CO3. Place the covered crucible over a moderately low flame and increase the flame gradually to a maximum (approximately 1100 oC) and maintain this temperature until the mass is quiescent (about 45 min). Remove the burner, lay aside the cover of the crucible, grasp the crucible with tongs, and slowly rotate the crucible so that the molten contents spread over the sides and solidify as a thin shell on interior. Set the crucible cover aside to cool. Rinse off the outside of the crucible and place the crucible on its side in a 300 ml casserole about one third full of water. Warm the casserole and stir until the cake in the crucible disintegrates and can be removed easily. By means of a glass rod, lift the crucible out of the liquid, rinsing it thoroughly with water, Rinse the cover and crucible with HC1 (1+3): then add the rinse to the casserole. Very slowly and cautiously add 20 ml of HCl (specific gravity 1.19) to the covered casserole. Remove the cover and rinse. If any gritty particles are present, the fusion is incomplete and the test must be repeated, using a new sample. NOTE : Subsequent steps of the test method shall be followed exactly for accurate results. B.4.2 Evaporate the solution to dryness on a steam bath (there is no longer a gelatinous appearance). Without heating the residue any further, treat it with 5 ml to 10ml of HCl, wait at least 2 min, and then add an equal amount of water. Cover the dish and digest for 10 min on the steam bath or a hot plate. Dilute the solution with an equal volume of hot water, immediately filter through medium-textured paper and wash the separated SiO2 thoroughly with hot HCl (1+99), then with hot water. Reserve the residue. Again evaporate the filtrate to dryness, and bake the residue in an oven for 1 h at 105 oC to 100 oC to cool, add 10 ml to 15 ml of HCl (1+1) and digest on the steam bath or hot plate for 10 min. Dilute with an equal volume of water, filter immediately on a fresh filter paper, and wash the small SiO2 residue thoroughly as described in the above paragraph.

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B.4.3 Transfer the filter papers and residue to a weighed platinum crucible, dry and ignite, at first slowly until the carbon of the paper is completely consumed without inflaming, and finally at 1100 oC to 1200 oC for 1 h. Cool in a desiccator and weigh (m1). Reignite to constant mass. B.4.4 Treat the SiO2 thus obtained, which will contain small amounts of impurities, in the crucible with 1 ml or 2 ml of water, 2 drops of H2SO4 (1+1), and about 10 ml of HF, and evaporate cautiously to dryness. Finally, heat the small residue at 1050 oC to 1100 oC for 5 min, cool in a desiccator, and weigh (m2). The difference between this mass and the mass previously obtained represents the mass of SiO2. NOTE : Consider the weighed residue remaining after the volatilization of SiO2 as combined aluminum and ferric oxides and add it to the result obtained in the determination of the ammonium hydroxide group. B.5 Calculation Calculate the content (per cent) of the silicon dioxide (per cent) in the sample from the following equation: SiO2 = {m1-m2}200 Where, SiO2 is the content of the silicon dioxide (per cent)

m1, m2 are the masses of the 1st and 2nd precipitates (g) as per B.4.3 and B.4.4 respectively.

B.6 Repeatability and reproducibility

The standard deviation of repeatability is 0.07 per cent

The standard deviation of reproducibility is 0.10 per cent

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APPENDIX C

DETERMINATION OF RESIDUE INSOLUBLE IN HYDROCHLORIC ACID AND POTASSIUM HYDROXIDE

C.1 Principle This is a conventional method in which the insoluble residue in cements is obtained by treating with a hydrochloric acid solution. The residue from this treatment is then treated with a boiling solution of potassium hydroxide. The residue is determined gravimetrically after ignition. C.2 Procedure To (1 + 0.05) g of cement (m1), placed in a porcelain dish, add 25 ml of cold water and disperse using a glass-stirring rod. Add 40 ml of concentrated hydrochloric acid. Heat the solution gently and crush the sample with the flattened end of a glass-stirring rod until decomposition of the cement is complete. Evaporate to dryness on a water bath. Repeat the operation twice more with 20 ml concentrated hydrochloric acid.

Treat the residue from the last evaporation with 100 ml of dilute hydrochloric acid (1+3). Re-heat, filter through a medium filter paper and wash with almost boiling water at least ten

times until free from Cl -

ions, tested by the silver nitrate test. (Add several drops of silver nitrate solution, check the absence of turbidity of precipitate in the solution. If present, continue washing while carrying out periodic checks until the silver nitrate test is negative.) Transfer the filter and its contents to a 250 ml conical flask fitted with a bulb condenser and add 100 ml of the potassium hydroxide solution (Dissolve 250 g. KOH in water and make up to 1000 ml). Leave to stand for 16h at room temperature and then boil the solution under reflux for 4 h. Filter on a medium filter paper and wash with water then with 100ml of hydrochloric acid

(1 + 9) and finally with almost boiling water until free from Cl - ions, tested by the silver

nitrate test. Ignite at 975 ± 25 0C for 15 minutes then check for constant mass. In general, an ignition period of 30 min is sufficient for obtaining constant mass (m2).

C.3 Expression of results

The insoluble residue is calculated in per cent from the formula: Insoluble residue = m2 x 100

m1

Where: m1 is the mass of the test portion, in grams; and m 2 is the mass of the ignited insoluble residue, in grams.

C.4 Repeatability and reproducibility The standard deviation for repeatability is 0.15 per cent The standard deviation for reproducibility is 0.18 per cent

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APPENDIX D DETERMINATION OF FREE CALCIUM OXIDE CONTENT

D.1 Reagents

Use only reagents of analytical grade and distilled water, or water of equal purity.

D.1.1 Butanoic acid, 3-oxo-ethyl ester (= ethyl acetoacetate)

D.1.2 Butane 2 –ol

D.1.3 Propane 2-ol

D.1.4 Indicator (0.1 g of bromophenol blue in 100 ml of ethanol)

D.1.5 Hydrochloric acid (0.100 M)

D.2 Apparatus

D.2.1 Balance, capable of weighing to an accuracy of 0.0001 g or better

D.2.2 Test sieve, with 0.063 mm sieve cloth conforming to ISO 565 test sieve

D.2.3 Mortar and pestle, or similar equipment for grinding

D.2.4 Desiccator, containing a drying agent, e.g. silica gel

D.2.5 Flask, 250 ml.

D.2.6 Spiral reflux condenser

D.2.7 Absorption tube, filled with sodium hydroxide on an inorganic carrier (to protect the contents of the flask and the condenser from reacting with atmospheric carbon dioxide). D.2.8 Filter crucible, with pore sizes of 0.004 mm to 0.010 mm. NOTE : Alternatively also a filter funnel, in which a filter paper with fine pores of a diameter of approximately 0.002 mm and a filter paper with medium pores of a diameter of approximately 0.007 mm can be placed may be used. D.3 Procedure

D.3.1 Preparation of sample

Subdivide the laboratory sample, prepared in accordance with Appendix A of SLS 107 : Part 1: 2002 by a suitable method to obtain a sub sample of about 100 g. Pass this sub sample through the test sieve (D.2.2). Grind any residue in the mortar (D.2.3) until all the sub sample passes through the sieve completely. Homogenize the total sub sample and place it in the desiccator (D.2.4) until tested.

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D.3.2 Determination Place a weighed portion of 1.0 g to 1.5 g of the subsample prepared in accordance with D.3.1 into the 250 ml flask (D.2.5) and add a mixture of 12 ml butanoic acid, 3-oxo-ethyl ester (D.1.1) and 80 ml butan-2-ol (D.1.2). Fit the flask with the spiral reflux condenser (D.2.6) and the absorption tube (D.2.7) and boil for 1 h. Filter the warm mixture through the filter crucible (D.2.8). Wash the residue with propan-2- ol (D.1.3) until the filtrate reaches a volume of 50 ml. If the filtrate is cloudy, reject it and repeat the extraction with a new weighed portion of the sub sample. Add a few drops of bromophenol blue indicator (D.1.4) to the filtrate and titrate with hydrochloric acid (D.1.5) until the colour changes to yellow. Record the volume V of hydrochloric acid used. D.3.3 Calculations The free calcium oxide content (MCaO), expressed as a percentage by mass of the dry fly ash, shall be calculated from the following equation : MCaO = 28.04 x C x V

m x 1000 where C is the concentration in mol/l of the hydrochloric acid solution V is the volume in ml. of hydrochloric acid solution used for titration; and m is the weighed proportion in g. of the dried fly ash D.4 Results The mean value of two determinations, calculated to two decimal places and expressed to one decimal place, shall be taken as the free calcium oxide content of thee sample. D.5 Repeatability and reproducibility The standard deviation for repeatability is 0.02 per cent by mass (provisional value). The standard deviation for reproducibility is 0.04 per cent by mass (provisional value).

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APPENDIX E SAMPLING AND CRITERIA FOR CONFORMITY

The sampling scheme given in this Appendix should be applied where compliance of a lot to the requirements of this specification is to be assessed based on statistical sampling and inspection. Where compliance with this specification is to be assured based on manufacture’s control systems coupled with type testing and check tests or any other procedure, appropriate schemes of sampling and any other inspection procedure should be adopted. E.1 Lot In any consignment, all the packages of cement or a quantity of bulk cement belonging to one batch of manufacture or supply shall constitute a lot. E.2 General requirements of sampling E.2.1 Precautions shall be taken to transfer the sample into a clean, dry and air tight containers and marked with necessary details of sampling. E.2.2 Sampling instruments shall be clean and dry when used. E.3 Sampling instruments A sampling tube or an appropriate instrument shall be used ( see Figure 3).

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E.4 Scale of sampling Samples shall be tested for each lot for ascertaining its conformity to the requirements of this specification. E.4.1 Sampling from bags E.4.1.1 The number of bags to be selected from the lot shall be in accordance with Table 3. TABLE 3 : Scale of sampling Lot size Sample size

number of bags

Up to 150 5

151 to 300 10

301 to 600 15

601 to 800 20

801 to 1000 25

1001 and above 30

These bags shall be chosen at random, from the lot. To ensure the randomness of selection a method given in SLS 428 shall be used. Alternatively all the bags in the lot may be arranged in a serial order and starting from any bag, Every rth bag be selected till the requisite number is obtained, r being the integral part of N/n where N is the lot-size (number of bags in a lot) and n is the sample size (number of bags selected). E.4.1.2 Preparation of sample Equal quantities of cement shall be taken from each bag selected as in E.4.1.1 and mixed together to form a composite sample of approximately 10 kg. E.4.2 Sampling from bulk container E.4.2.1 A gross sample shall be taken from the lot by taking increments at regular intervals when the cement is being charged into the container or being discharged from the container. The number of increments shall be such that one increment is taken for 10 tonnes of cement. Each increment shall weigh about 2 kg. All the increments taken as above shall be mixed together to form a composite sample of cement. E.4.3 Sampling from wagon/truck E.4.3.1 The mass of the gross sample to be drawn from the lot shall depend on the lot size.

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E.4.3.2 A sufficient number of increments shall be drawn from evenly distributed points of each wagon/truck to obtain a gross sample of 2 kg. (approximately) per 10 tonnes of cement in the lot or part of it. The increments taken as above shall be mixed together to form a composite sample. NOTE

1. Increments shall be taken by using a sampling tube or appropriate sampling instrument.

2.The minimum mass of the gross sample to be drawn shall be 10 kg. Sufficient number of increments shall be taken when the lot size is less than 50 tonnes. E.4.4 Preparation of laboratory sample The composite sample prepared as in E.4.2.1 or E.4.3.2 shall be reduced to obtain the laboratory sample of 10 kg. NOTE : Heaping into a cone and quartering method shall be applied for reducing the size

of the sample.

E.5 Number of tests

E.5.1 Each bag selected as in E.4.1.1 shall be inspected for marking and packaging requirements. (see 7 and 8) E.5.2 In case of packaged material, the composite sample prepared as in E.4.1.2 shall be tested for all the requirements (see 6) given in the standard. In case of bulk material, the laboratory sample prepared in accordance with E.4.4 shall be tested for all the requirements (see 6) given in this standard. NOTE : Tests shall be carried out as prescribed in this standard.

E.6 Criteria for conformity A lot shall be declared as conforming to the requirements of this specification if the following conditions are specified. E.6.1 Each bag inspected as in E.5.1 satisfies the relevant requirements. E.6.2 The test results on each composite sample or the laboratory sample when tested as in E.5.2 satisfy the relevant requirements.

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APPENDIX F

DETERMINATION OF CLAY CONTENT OF LIMESTONE

F.1 This appendix specifies a method for the determination of the methylene blue value of the 0/2 mm fraction in the fine aggregates or all-in aggregates (MB). A procedure for the determination of the methylene blue value of the 0/0, 125 mm fraction (MBF) is specified in annex 1. Principle Increments of a solution of methylene blue are added successively to a suspension of the test portion in water. The adsorption of dye solution by the test portion is checked after each addition of solution by carrying out a stain test on filter paper to detect the presence of free dye. When the presence of free dye is confirmed the methylene blue value (MB or MbF) is calculated and expressed as grams of dye adsorbed per kilogram of the size fraction tested. NOTE : A conformity check, adding a single quantity of dye solution equivalent to a specified limiting value and which may be used as part of a production control process, is described in annex II. F.2 Reagents F.2.1 Dye solution, Solution of standard or technical quality methylene blue, (10.0 ± 0.1) g/l (see annex III). The maximum period of use of the solution shall be 28 days. It shall be stored away from light. F.2.2 Distilled or demineralized water: F.2.3 Kaolinite, of known methylene blue value (MBK) (see annex IV). NOTE Kaolinite of MBK value between 1g and 2g per 100g of Kaolinite is preferable in order to avoid excessive use of dye. F.3 Apparatus All apparatus shall conform to the general requirements of BS EN 932-5 F.3.1 Burette, with capacity of either 100 ml or 50 ml and graduation of either 1/10 ml or 1/5 ml, or one 5 ml and one 2 ml micro-pipette. F.3.2 Filter paper; quantitative and ash-free (<0.010%); 95 g/m2; thickness 0.20 mm; filtration speed 75 s, pore size 8 µm. F.3.3 Glass rod, length 300 mm; diameter 8 mm.

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F.3.4 Impeller agitator; capable of controlled variable rotation rates up to (600 ± 60) min-1 with three or four impeller blades of (75 ± 10) mm diameter. NOTE: Alternative types of mixer can be used if it can be shown that results obtained agree with results produced using an impeller agitator as specified above. F.3.5 Balance, readable to 0.1% of the mass to be weighed. F.3.6 Stopwatch or stopclock; readable to 1 s. F.3.7 Test sieve, 2 mm aperture, with guard sieve (if necessary). F.3.8 Beaker; glass or plastic, capacity about 1 l or about 2 l. F.3.9 Flask, glass, capacity 1l. F.3.10 Ventilated oven, thermostatically controlled to maintain a temperature of (110 ± 5) °C. F.3.11 Thermometer, readable to 1 °C. F.3.12 Spatula. F.3.13 Desiccator; F.4 Preparation of Test Portions The laboratory samples shall be reduced in accordance with BS EN 932-2 to produce a sub sample containing at least 200 g of 0/2 mm particle size. Dry the subsample at (110 ± 5) °C to constant mass and allow to cool. Sieve the dry subsample on a 2 mm sieve protected if necessary by a guard sieve, and using a sieve brush to ensure effective separation and collection of all particles in the 0/2 mm fraction. Discard any particles retained on the 2 mm sieve and, if necessary, reduce the fraction passing the 2 mm sieve in accordance with prEN 932-2 to obtain a test portion of mass at least 200 g. The mass of the test portion shall be larger than 200 g but not of an exact predetermined value. Weigh the test portion and record the mass to the nearest 1 g as M1. F.5 Procedure F.5.1 Description of the Stain Test After each injection of dye, the stain test consists of taking a drop of suspension by means of the glass rod and depositing it on the filter paper. The stain, which is formed, is composed of

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a central deposit of material, of a generally solid blue colour, surrounded by a colourless wet zone. The amount of drop taken shall be such that the diameter of the deposit is between 8 mm and 12 mm. The test is deemed to be positive if, in the wet zone, a halo consisting of a persistent light blue ring of about 1 mm is formed around the central deposit. NOTE: As the end-point is approached, the halo will appear, but can then disappear again, because the clay minerals can take some time to complete their adsorption of the dye. For this reason the end-point is confirmed by repeating the stain test at 1 min intervals for 5 min without adding more dye solution, F.5.2 Preparation of Suspension Place (500 ± 5) ml of distilled or demineralized water in the beaker and add the dried test portion stirring well with the spatula. Stir the dye solution (see F.2.1) or alternatively mix it thoroughly. Fill the burette with dye solution and return the stock of dye solution to a dark place. Set the agitator to a speed of 600 min-1 and position the impeller about 10 mm above the base of the beaker. Switch on the agitator and start the stopwatch, agitating and contents of the beaker for 5 min at (600 ± 60) min-1 and subsequently (see F.5.3) agitate continuously at (400 ± 40) r/min for the remainder of the test. If insufficient fines are present in the test portion to obtain a halo, Kaolinite should be added together with additional dye solution as follows. Add to beaker (30.0 ± 0.1) g of Kaolinite (F.2.3) dried at (110 ± 5) °C to constant mass; Add V’ ml of dye solution to the beaker where V’ = 30 MBK, is the volume of dye solution adsorbed by 30 g of Kaolinite.

F.5.3 Determination of the quantity of dye adsorbed Place the filter paper (F.3.2) on top of an empty beaker, or some other suitable support, so that most of its surface is not in contact with any solid or liquid. After agitating for 5 min at (600 ± 60) min-1 , inject a dose of 5 ml of dye solution (see F.2.1) into the beaker; agitate at (400 ± 40) min-1 for at least 1 min and carry out a stain test (see F.5.1) on the filter paper. If after the addition of this initial 5 ml of dye solution the halo does not appear, add a further 5 ml of dye solution, continue agitating for 1 min, and carry out another stain test. If a halo still does not appear, continue agitating, making additions of dye and doing stain tests in this manner until a halo is observed. When this stage is reached, continue agitating and without further additions of dye solution, perform stain tests at 1 min intervals.

If the halo disappears during the first 4 min, add a further 5 ml of dye solution. If the halo disappears during the fifth minute, add only 2 ml of dye solution. In either case, continue agitating and doing stain test until a halo persists for 5 min.

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Record the total volume of dye solution V1 added to produce a halo that persists for 5 min, to the nearest 1 ml.

NOTE: Containers should be cleansed thoroughly with water as soon as the tests are completed. Traces of any detergents used should be removed by thorough rinsing. It is recommended that containers used in methylene blue tests are reserved specifically for that test. F.6. Calculation and expression of results

The methylene blue value, MB, expressed in grams of dye per kilogram of the 0/2 mm fraction is given by the following equation: MB = V1 x 10

M1 Where M1 is the mass of the test portion, in grams: V1 is the total volume of dye solution injected, in millilitres. If the test is carried out with the addition of Kaolinite, the above equation becomes: MB = V1 – V’ x 10

M1 Where V’ is the volume of dye solution adsorbed by the Kaolinite, in millilitres. F.7 Test report F.7.1 Required data

a) reference to this Standard; b) identity of laboratory; c) identification of the sample; d) description of the material tested; e) MB value; f) date of receipt of sample; and g) sampling certificate if available.

F.7.2 Optional data

a) name and location of the sample source; b) description of the sample reduction procedure; c) date of test.

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Annex – I (Normative) PROCEDURE FOR THE DETERMINATION OF THE METHYLENE BLUE VALUE (MBF) OF THE 0/0.125 MM FRACTION I.1 Prepare test portions as specified in F.4 and follow the test procedure in F.5 but with a

test portion mass M1 of (30.0 ± 0.1) g of the 0/0. 125 mm fraction. I.2 Calculate the methylene blue value (MBF) in grams of dye per kilogram of the 0/0. 125

mm fraction as:

MBF = V1 x 10

M1 Where M1 is the mass of the test portion, in grams; V1 is the total volume of dye solution added, in milliliters.

I.3 Record the MBF value to the nearest 0.1 g of dye per kilogram of the 0/0.125 mm

fraction. I.4 Test reports shall include appropriate information in accordance with Clause F.7.

Annex - II (Informative) TEST OF CONFORMITY IN RELATION TO A SPECIFIED MB VALUE A check on conformity with a specified MB value can be carried out by making a addition of dye solution in the following manner: If the specified MB value expressed as grams of dye per kilogram of 0/2 mm fraction is MB1 then the volume of dye solution to be injected at one time, V2, is given by the following equation: V2 = MB1 X M1 + V’ 10 Where M1 is the mass of the test portion in grams MB1 is the specified MB value in grams of dye per kilogram of 0/2 mm fraction V’ is the volume of dye solution in millilitres adsorbed by any added Kaolinite.

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After preparation of a test portion in accordance with clause F.4 the suspension should be prepared using the test portion, the water and, if necessary the Kaolinite, all in accordance with F.5.2 but including V2 ml of dye solution.

The stain test should be carried out after stirring the suspension for 8 min at (400 ± 40) min-1. If the stain test (see F.5.1) is positive, the sand can be assumed to conform to the specification. If this stain test is negative however, the complete determination described in F.5.3 should be carried out.

Annex - III (Normative) PREPARATION OF 10 G/L METHYLENE BLUE SOLUTION III.1 Prepare the 10 g/l dye solution following the procedure given in III.1.1 to III.1.7. III.1.1 Use methylene blue; (C16H18CIN3S, nH2O (n = 2 to 3 purity ≥ 98.5 per cent)

III.1.2 Determine the water content W of the methylene blue powder as follows

Weigh approximately 5 g of methylene blue powder and record the mass to the nearest 0.01 g as Mh. Dry this powder at (100 ± 5) °C to constant mass. Cool in the desiccator and then weigh immediately after taking out of the desiccator the dry mass to the nearest 0.01 g as Mg. NOTE: At temperatures above 105 °C, methylene blue powder can be modified. Calculated and record the water content W to the nearest decimal place from the following equation: W = Mh - Mg X 100 Mg

Where Mh the mass of the methylene blue powder, in grams; Mg is the mass of the dried methylene blue powder, in grams. The water content shall be determined for the preparation of every new batch of dye solution. III.1.3 Take a mass of methylene blue powder of [(100+W)/10] g ± 0.01 g (equivalent to 10 g of dry powder). III.1.4 Warm 500 ml to 700 ml of distilled or demineralized water in a beaker to a temperature not exceeding 40 °C.

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III.1.5 Agitate the contents of the beaker whilst slowly pouring the methylene blue powder into the warm water. Continue to agitate for 45 min, until complete dissolution of the powder, and then allow to cool to 20 °C. III.1.6 Pour into a flask of capacity 1l, rinsing with distilled or demineralized water to ensure complete transfer of all dye into the flask. Make sure that the flask and the water are at a temperature of (20 ± 1) °C to conform with the calibration of the flask and add more distilled or demineralized water to the 1l graduation mark. III.1.7 Shake the flak to ensure complete dissolution of the powder and pour into a conservation bottle in tinted glass. III.2 The following details shall be marked on the conservation bottle:

a) 10 g/l methylene blue solution b) date of preparation c) limit date of use

III.3 Methylene blue solution shall not be used more than 28 days after preparation. The stock of dye solution shall be stored in a dark place.

Annex- IV (Normative) PROCEDURE FOR THE DETERMINATION OF THE METHYLENE BLUE VALUE OF KAOLINITE (MBK) IV.1 Dry the Kaolinite at (110±5) °C to constant mass. IV.2 Weigh (30.0±0.1) g of dry Kaolinite IV.3 Pour the (30.0±0.1) g of Kaolinite into the beaker (F.3.8) together with 500 ml of demineralized or distilled water. IV.4 Agitate for 5 min at (600 ± 60) min-1 with the impeller about 10 mm above the base of the container and subsequently agitate continuously at (400±40) min-1 for the remainder of this determination. IV.5 Inject a dose or 5 ml of 10 g/l dye solution into the beaker and, after at least 1 min of agitating at 400±40) min-1. Carry out a stain test (see F.5.1) on the filter paper. IV.6 If necessary continue to add dye solution in 5 ml doses until a positive results is obtained without adding any more solution. Leave the adsorption of blue which is not instantaneous, to proceed while carrying out stain tests each minute. If the light blue ring disappears on the fifth stain further increments of 2 ml of dye shall be added. Each addition shall be followed by tests carried out at intervals of 1 min. These operations shall be repeated until the test remains positive for 5 consecutive min. The determination is then complete.

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IV.7 Record the total volume of dye solution adsorbed as V’ millilitres. IV.8 Calculated and record the methylene blue value of the Kaolinite to the nearest, 0.1 g of dye per 100 g of Kaolinite from the following equation: MBK = V’ / 30 Where V’ is the total volume of dye solution adsorbed in millilitres. NOTE: A test on Kaolinite of known MBK value should be carried out at regular intervals to check the constancy of results. This procedure should also be used to check a new dye solution.

APPENDIX G

DETERMINATION OF ORGANIC CARBON IN LIMESTONE G.1 SCOPE This method specifies methods for determination of the total organic carbon content (TOC) in limestone. G.2 BLANK DETERMINATIONS Carry out a blank determination without a sample following the same procedure and using the same amounts of reagents. Correct the results obtained for the analytical determination. G.2.1 Sampling and sample preparation Depending on the size of the raw material a sample of at least 1 kg up to 10 kg shall be taken by the procedure described in ISO 11464 dried, crushed, reduced and ground to form a representative laboratory sample for analysis. The laboratory sample shall pass a sieve of 90 µm mesh size conforming to ISO 3310-1. The drying process shall be modified if necessary to accommodate samples known to contain high contents of volatile organic carbon. G.2.2 General test principles In general all procedures consist of the following stages:

- Decarbonation of the original limestone sample - Purification of the carrier gas, if it is not of high purified quality. - Oxidation of the organic carbon matter. - Purifying of the CO2 produced by oxidation - Measurement of the CO2 content

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G.3 REAGENTS G.3.1 General requirements

Use only reagents of analytical quality. Reference to water means distilled water, or water of equal purity. Unless otherwise stated means percent by mass. The concentrated liquid reagents used in this standard have the following densities in grams per cubic centimeter at 20 °C. Ammonia solution 0.88 to 0.91 Hydrochloric acid 1.18 to 1.19 Hydrogen peroxide 1.11 Nitric acid 1.40 to 1.42 Phosphoric acid 1.71 to 1.75 Sulphuric acid 1.84 The degree of dilution a always given as a volumetric sum, for example: dilute hydrochloric acid 1+2 means that 1 volume of concentrated hydrochloric acid is to be mixed with 2 volumes of water. G.3.2 Ammonia solution (NH3 .H2O). G.3.3 Calcium chloride, anhydrous (CaCl2). G.3.4 Calibration reagent. Metal, for example iron with known carbon content. G.3.5 Carbon dioxide in oxygen, 0.95 vol. per cent and 19 vol. per cent. G.3.6 Carrier gases, depending on application: air, oxygen, nitrogen or argon, free of carbon dioxide and hydrocarbons. G.3.7 Chromic acid.(see NOTE) Dissolve 5 g of chromium trioxide (G.3.8) in 10 ml of water. Add Sulphuric acid (G.3.13) with stirring, until the chromium oxide, which initially precipitates, is just redissolved. NOTE : Warning – Chromic acid and its mixtures with sulphuric acid, may cause cancer. Also the vapour phase is dangerous. It is therefore, necessary to take special precautions when working with chromic acids. The use of chromic acid resistant fume cupboards and acid resistant gloves is obligatory. G.3.8 Chromium trioxide (CrO3) G.3.9 Concentrated Hydrochloric acid (HCl) G.3.10 Concentrated Hydrogen peroxide (H2O2)

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G.3.11 Concentrated Nitric acid (HNO3) G.3.12 Concentrated Phosphoric acid (H3PO4) G.3.13 Concentrated sulphuric acid (H2SO4) G.3.14 Copper (Cu), free of carbon G.3.15 Copper oxide (CuO). Particle size of 0.6 mm to 1.2 mm. G.3.16 Dilute hydrochloric acid 1 + 5 G.3.17 Dilute nitric acid 1+ 9 G.3.18 Iron (Fe), free of carbon G.3.19 Lead chromate (PbCrO4) G.3.20 Magnesium perchlorate (Mg(ClO4)2), anhydrous, particle size 0.6 mm to 1.2 mm G.3.21 Magnesium sulphate, anhydrous (MgSo4). G.3.22 Magnesium turnings according to Grignard (Mg) G.3.23 Manganese dioxide (MnO2). Particle size of 0.6 mm to 1.2 mm. G.3.24 Oxalic acid dihydrate (C2H2O4 2H2O) G.3.25 Oxidation catalyst. lgnited silver permanganate with a composition of approximately AgMnO4. G.3.26 Oxidizing mixture to 85 ml sulfuric acid (G.3.13) in a 250 ml beaker add in order 15 ml phosphoric acid (G.3.12) 20 g phosphorus pentoxide (G.3.28) 15 g potassium dichromate (G.3.30) and 1 g potassium iodate (G.3.31) Carefully heat the mixture to about 170 °C maintaining the temperature for about 5 min and occasionally stirring with a thermometer. Allow the mixture to cool to room temperature and store it in a stoppered bottle. G.3.27 Paraffin G.3.28 Phosphorus pentoxide (P2O5) G.3.29 Platinum (1 per cent) on alumina pellets (Pt). Particle size 3.2 mm, oxidation catalys. G.3.30 Potassium dichromate (K2Cr2O7) G.3.31 Potassium iodate (KIO3)

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G.3.32 Silver gauze (Ag). Wash commercially available silver gauze with ammonia solution (G.3.2) nitric acid 1+9 (G.3.17) and hydrogen peroxide (G.3.10). Rinse the gauze with water between each washing. G.3.33 Sodium hydroxide (NaOH) G.3.34 Sodium hydroxide (NaOH) on a high surface dark coloured siliceous carrier G.3.35 Sodium hydroxide solution . Dissolve 40 g sodium hydroxide (G.3.33) in water and make up to 1 000 ml. Store in a polyethylene container. G.3.36 Sodium iodide (Nal) G.3.37 Sodium iodide solution. Add 10 ml hydrochloric acid (G.3.9) and 150 g of sodium iodide (G.3.36) into a 11 volumetric flask and dilute to 11 with water. G.3.38 Zinc wool (Zn) G.4 GENERAL APPARATUS G.4.1 Balances capable of weighing to an accuracy + 0.0005g G.4.2 Laboratory ovens capable of maintaining at the following temperatures (75+5) 0C G.5 WET OXIDATION METHOD (REFERENCE METHOD) G.5.1 Principle The carbon dioxide in the limestone is driven off by use of phosphoric acid (G.3.12) The remaining organic carbon is then oxidized to carbon dioxide with a strong oxidizing reagent mixture (G.3.26). The liberated carbon dioxide is absorbed on an inorganic carrier impregnated with sodium hydroxide (G.3.34) in a U-tube. The increase in mass is directly proportional to the organic carbon content in the sample.

G.5.2 Apparatus The apparatus is illustrated in Figure 4. To general reduced pressure in the apparatus a small vacuum pump or an aspirator is used. The absorption tube (see Figure 4, No. 8) is filled approximately two-thirds of its volume with the absorbent for carbon dioxide (G.3.34) and with magnesium perchlorate (G.3.20). The absorption tube is then inserted into the apparatus as shown in Figure 4 drawing through it about 4 l of carrier gas (G.3.6). At this time the apparatus should be checked for leaks by turning off the drying tower tap whilst keeping the small vacuum pump or the aspirator trap fully open. If leaks are absent the gas flow through the bubble counter stops completely. After checking for leaks, the taps of the absorption tube are to be closed, it is transferred to a desiccator for 10 min, weighed to an accuracy of 0.0005 g (mu1), and reassembled as shown in Figure 4.

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Key 1 Drying tower for carrier gas containing a carbon dioxide absorbent (G.3.34) 2 Safety trap 3 Inlet tube for the oxidizing mixture (G.3.26) with glass rod stopper 4 150 ml round bottom distillation flask 5 100 ml sharp bottom flask with 50 ml chromic acid (G.3.7) 6 Absorption tube filled (in order upwards) with zinc wool (G.3.38), lead chromate

(G.3.19) and silver gauze (G.3.32). The materials are fixed in place with cotton wool plugs

7 Absorption tube filled magnesium per-chlorate (G.3.20), fixed in place with cotton wool 8 Absorption tube with a total volume of approximately 11 cm3 containing, in order,

absorbent for carbon dioxide (G.3.34) and magnesium perchlorate (G.3.20), fixed in place with cotton wool plugs

9 Bubble counter, containing concentrated sulfuric acid (G.3.13) 10 Vacuum The use of acid resistant fume cupboards and acid resistant gloves is obligatory.

FIGURE 4 - Apparatus for TOC determination by wet oxidation

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G.5.3 Procedure Weigh to an accuracy of ± 0.0005 g, (1.00±0.05) g of limestone (M1). Transfer to the 150 ml round flask, add 2 ml of water and 30 ml of phosphoric acid (G.3.12). heat the mixture and boil gently for 4 min to expel the carbon dioxide. Cool the mixture and connect the flask to the apparatus. Substitute for the absorption tube (see Figure 4, no. 8) a glass tube and pass 2 l of carrier gas (G.3.6) through the apparatus to clear the system of any carbon dioxide. Fit the weighed absorption tube again to the apparatus and check once more for leaks. Open the taps of the absorption tube2. Add approximately 30 ml of oxidizing mixture (G.3.26) to the flask through the inlet tube lifting the glass rod stopper. At this stage the flow rate of the carrier gas (G.3.6) shall procedure about 2 bubbles per second. Heat the sample mixture in the round bottom flask gently to boiling and keep at boiling for 4 min. Then remove the heater and whilst cooling pass approximately 3 l of carrier gas (G.3.6) through the system. Close the taps of the absorption tube (see NOTE). Transfer it to a desiccator, allow to cool for 30 min and weigh to an accuracy of ± 0.0005 g, (Mu2). NOTE : when the white colour has extended along the first halt of the tube, change the absorbent. G.5.4 Calculation Calculate the total organic carbon content in percent using the formula: TOC = Mu2 - Mu1 x 27,29

M1 Where Mu1 is the mass of the absorption tube before absorption of carbon dioxide in grams;

Mu2 is the mass of the absorption tube after absorption of carbon dioxide in grams;

M1 is the mass of the sample in grams.

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APPENDIX H ADDENDUM TO THE FOREWORD

Portland limestone cement (PLC) is not a cement used worldwide1. However, it was considered opportune to introduce it to Sri Lanka because of its many beneficial properties, some of which are of considerable usefulness to overcome specific problems seen in our construction industry. PLC reduces the clinker content and introduces limestone, which means less burning, consumption of less energy in pyro-processing and comminuting2,use of less limestone overall, and hence a reduction of CO2 emissions making the cement more environmentally friendly. Introduction of efficient milling systems for grinding reduces electrical power, thus lowering CO2 emission from the power station. Lesser use of clinker reduces CO2 emissions from the cement plant3. As pure limestone or calcite is not normally available to cement plants, suitable limestone is specified2 by imposing limits on CaCO3 content, clay content and total organic carbon content. Greater clay content leads to increased water demand and reduced frost resistance. A limit is imposed on total organic carbon content because organic matter if present decays rapidly. Although BS EN 1974 allows limestone contents up to 35 per cent in PLC, BS 8500 : Part 15 rules out the use of limestone contents exceeding 20 per cent. At present PLC cements containing more than 20 per cent limestone are not recommended for use in structural concrete1. Even for limestone contents up to 20 per cent , BS 8500 : Part 26 imposes certain restrictions. In line with this thinking, this Sri Lanka Standard limits that limestone content to a maximum of 15 per cent. There are three mechanisms by which finely divided limestone can modify properties of Portland cement1,3. Firstly, it improves the particle size grading of the cement paste in concrete, thus improving particle packing which reduces the water demand and reduces bleeding or segregation. Secondly, hydration rate is increased with fine particles of limestone providing nucleation sites for Ca (O)H)2 crystallization. Lastly, limestone interacts with the hydrating C3A to form a monocarboaluminate phase and to become partially incorporated in the C-S-H phase. This monocarboaluminate phase is stable and co-exists with the monosulphate phase, which is the normal product of reaction between gypsum and C3A. However, the practical effects of limestone additions in small amounts are physical, improving particle packing and providing nucleation sites for clinker hydration products2. To derive fully the benefits of PLC, it should be ground to a higher fineness than OPC. This generally requires closed circuit milling with high efficiency separators1,2. The limestone is normally interground with clinker, which makes limestone to be more finely ground than clinker as limestone is the softer of the two. This enhances the reactivity of the CaCO3 and improves particle packing. The fineness of PLC is important1 and hence it is specified in this standard. It is normally lighter in colour than its parent OPC1. PLC should be stored under very dry conditions7, since it can react rapidly with contaminations of moisture due to its higher fineness. Variability of PLC is less than that of blended cements as limestone quality can be carefully maintained over a longer period of time, as limestone deposit is often maintained by

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the cement manufacturer1 or limestone used is part of the raw material reserves used for clinker production. There is a common belief that the finer a powdered material, then the greater becomes its water demand when it is made into an aqueous suspension. Such thinking assumes that the relative particle size distribution remains unchanged8. The easily ground limestone usually has a wide particle size distribution which allows the limestone particles to fill the gaps between the clinker particles, reducing the water demand and densifying the structure of hardened cement paste2. Bleeding is a form of segregation in which some of the water in the mix tends to rise to the surface of freshly placed concrete. This is caused by the inability to hold all of the mixing water when they settle downwards. Bleeding is decreased by increasing the fineness of cement, and PLC with a high fineness thus reduces bleeding9. Influence of PLC in heat of hydration and setting time was varied with some cement compositions recording an increase and other cement compositions recording a decrease2. The tendency to false set has been shown to be reduced with partial substitution of limestone for gypsum. Limestone in PLC improves the particle size distribution by making it broader. The fine particles displace some of the water from the voids between the coarser particles, making it available as an additional “internal lubricant”. Thus the concrete is less stiff and water retention is improved2. Since less water is needed to make a workable mix, water cement ratio can be reduced so that the strength is increased. Further, this means that less stiff concrete with PLC is more easily consolidated by vibration. In practical terms this means that a PLC mix is more workable, easy to compact, easy to pump leading to reduced wear and tear on pumping equipment. While good early moist curing is essential for blended cements with fly ash or Pozzolana, the long term strength of PLC may be superior even with somewhat poor curing conditions as a result of it is more rapid rate of initial hydration1. PLC has less cemenitious matter in comparison to OPC. So the performance of PLC containing greater than 5% limestone is akin to an OPC with less cementitious material10. In the case of this PLC which has a limestone content greater than 5%, it may be necessary to increase the cementitious content by the proportion of the filler content (i.e 15 %), if PLC is to be used in a concrete of a nominal mix or a prescribed mix11 unless test shows otherwise. This restriction is not applicable to design mixers. However, in the case of grade 15 concrete such an increase can be ruled out on the basis of increased strength likely from use of a lower water/cement ratio with PLC. Drying shrinkage and carbonation depths show mixed results, in some cases being increased and in some decreased in PLC when compared to OPC. The differences are of limited practical significance in the context of normal concrete mix variations2.

Permeability is somewhat reduced in PLC mixes, probably due more to a reduction in the connectivity of the pores rather than to their volume2, due to closer packing caused by broader particle size distribution of limestone. This accounts for better corrosion protection than in OPC.

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There are some concerns regarding thaumasite (CaSiO2. CaCO3.CASO4.15H2O) formation when PLC concrete is exposed to sulphate - bearing ground water; particularly at temperatures below 15 oC. Rate of deterioration is similar to OPC under sulphate attack when ettringite (C3A.3CaSO4.31H2O) rather than thaumasite is formed. In both these instances, rate of deterioration is governed by clinker C3A content. BS 85005 imposes restrictions on use of PLC for concrete foundations1 in certain soil condition, where use of OPC is acceptable. The performance of mineral admixtures is unaffected by limestone in PLC2.

Plastic shrinkage is greater when cement content in the mix is high, concrete stiffens earlier, concrete temperature is higher than ambient and evaporation is high. When these factors are prevalent, all types of cement used in concreting including PLC give rise to plastic shrinkage cracking, unless evaporation is prevented by placing and finishing fast , and covering plastic concrete very early to start curing soon7. PLC is unlikely to affect adversely the resistance of the concrete to fire or to abrasion12. Normal shutter / formwork removal times apply to PLC as initial set and early strength are only slightly less than those of OPC. Further, because of faster hydration reaction, PLC is not very dependent on the efficiency of long term curing. Although PLC has a slightly lower heat of hydration in comparison to OPC, it is not a low heat cement as C3S and C3A contents are not very much smaller than those of OPC, and because greater fineness causes faster hudration.7

REFERENCES 1. Moir, G.K. “Gaining Acceptance”, P67, International Cement Review, March 2003. 2. Detwiler, R.J. and Tennis, P.D., “The Use of Limestone in Portland Cement: A state

of the Art, Review”, 1996.Porltand Cement Association, USA. 3. Moir G.,” Minor Additional Constituents : Permitted Types and Benefits”,

Editors : Dhir, R.K. and Jones, M.R., Euro. - Cements – Inspect of ENU 197 on Concrete Construction, Proceedings of the National Seminar held at The University of Dundee on 15th September 1994, E&EN Spon, U.K., 1994

4. BS EN 197 –1 : 2000, “Cement – Part 1. Compositions, specifications and conformity

criteria for common cements”. 5. BS 8500-1:2002 “ Concrete – Complimentary British Standard to BSEN 206-1

Part 1 : Method of specifying and guidance for the specifier (See Table A.17) 6. BS 8500-2: 2002, “ Concrete – Complimentary British Standard to BSEN 206-1

Part 2: Specification for constituent materials and concrete (See Table 7 and 9) 7. Neville, A.M. “ Properties of concrete”, A Pitman International text.

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8. Jackson, P.J. “Manufacturing aspects of Limestone-filled cement”, Proceedings of a seminar on Performance of Limestone filled cements BRE, 28th November 1989.

9. Brookbanks, P. “Properties of fresh Cement”, Proceedings of a seminar on

performance of Limestone filled cements BRE, 28th November 1989. 10. Mathews, J.D. “Performance of Limestone Filler Cement Concrete”, Editor Dhir R.K

and Jones, M.R., Euro. - Cements – Inspect of ENU 197 on Concrete Construction, Proceedings of the National Seminar held at The University of Dundee on 15th September 1994, E&EN Spon, U.K., 1994.

11. Livesey , P. “Strength Development Characteristics of Limestone Filler cements”,

Proceedings of seminar on Performance of Limestone filled cements BRE, 28th November 1989.

12. BS 7583: 1996 “Specification for Portland limestone cement”

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Acom\kapila\PLC standard.doc