Concrete Mix Design - IS 10262-2019 - .pptx

Concrete Mix Design Lecture

1. INDIAN STANDARD CONCRETE MIX PROPORTIONING GUIDELINES IS 10262-2019

2. REFERRED STANDARDS IS Codes Title 269:2015 Specification for Ordinary Portland cement( 6 th Revision) 383 : 2016 Specification for coarse and fine aggregates from natural sources for concrete (3 rd Revision) 456 : 2000 Code of practice for ‘Plain and reinforced concrete’ (4 th Revision). 1199- 2018 Fresh concrete – Methods of sampling, testing & analysis (Part -6) 2386 : 1963 (Pt 3) Methods of test for aggregates for concrete: Part 3 Specific gravity, density, voids, absorption and bulking 1489 : 2015 (Pt 1 & 2) Specification for Portland pozzolana cement : Part 1 For fly ash based and part 2 calcined clay based, cement mortar and concrete (second revision) 3812:2013 (Pt 1) Specification for fly ash in cement, cement mortar and concrete(2th Revision) 9103 : 1999 Specification for admixtures for concrete (1 st revision) 15388 - 2003 Specifications for Silica Fumes 16714 – 2018 Ground Granulated Blast Furnace Slag for use in Cement, Mortar & Concrete - Specifications

3. IS:10262 – 2009 IS:10262 – 2019 The scope of this standard was very limited without giving due considerations to many factors & recent developments affecting the concrete mix proportioning. The scope of the standard has been enlarged to include different types & grade of concrete giving due considerations to various other important factors The standard has been divided to 5 major sections to include: General terms & conditions in a detailed manner, Design of ordinary & standard grades of concrete, HSC (M65 – M100), SCC & Mass concrete Initial data to be provided for mix proportioning has been made more encompassing by including the provisions of IS:383-2016, usage of admixtures Formula for Target Mean Strength has been refined to include new factor based on grade of concrete so as to ensure minimum margin between Characteristic strength & target mean strength. Calculations of Standard deviation has been detailed A graph of w/c ratio verses 28-D compressive strength of concrete has been introduced for OPC, PPC & PSC for assuming initial w/c ratio. The standard was applicable only for ordinary & standard grades of concrete up to M55. Illustrative examples for mix proportioning of concrete using PPC, OPC+fly ash, OPC+ GGBS, HSC, SCC & mass concrete has been included. Guidelines for usage of water reducing admixture has been introduced as an informatory annex Consideration of Air Content has been re-introduced in the design of normal (non-air entrained) concrete mix. Overview of Major Modifications in IS:10262 - 2019

4. First published - 1982 1 ST Revision – 2009 2 ND Revision - 2019 The standard has been divided into five sections as given below: General Ordinary and Standard grades of concrete High strength grades of concrete Self Compacting Concrete Mass Concrete MAJOR MODIFICATIONS MADE IN REVISED 2019 VERSION

5. MAJOR MODIFICATIONS MADE IN REVISED 2019 VERSION Contd … Formula for Target Mean Strength has been revised to include new factor based on grade of concrete to ensure minimum margin between Characteristic strength & target mean strength Calculations of Standard deviation has been detailed Data to be provided for mix proportioning has been made more encompassing to include provisions of IS:383-2016, usage of admixtures Addition of illustrative example for fly ash as one of the ingredient. Mix proportioning procedure for high strength concrete for M 65 or Above up to M100 Requirements for selection of water – cement ratio, water content and estimation of coarse aggregate content and fine aggregate content , requirements for trial mix, illustrative examples Addition of air content consideration in the normal concrete MAJOR MODIFICATIONS MADE IN REVISED 2019 VERSION Contd …

6. Relation between free water-cement ratio and 28 days Compressive strength of Concrete

7. A graph with 3 curve depicting the relationship between 28-days compressive strength of concrete & w/c ratio has been introduced for working out free w/c. Curve 1 – For expected cement 28-D strength of 33 and < 43 MPa, Curve 2 - For expected cement 28-D strength of 43 and < 53 MPa Curve 3 - For expected cement 28-D strength > 53 MPa In absence of actual cement strength Curve 1, 2 & 3 may be used for OPC33, OPC43 & OPC53 grade cements respectively While using PPC/PSC, if actual cement strength is available then any curve can be used based on the actual strength In absence of actual cement strength of PPC/PSC, use Curve 2. . MAJOR MODIFICATIONS MADE IN REVISED 2019 VERSION Contd …

8. Reduce by 10 kg for sub-angular aggregates, Reduce by 15 kg for gravel with some crushed particles (Earlier it was 20 kg) Reduce by 20 kg for rounded gravel (Earlier it was 25 kg) to produce same workability. The adjustments to be made in the water content (For 50mm slump) given in Table-4 for different shapes of aggregates has been revised as follows; MAJOR MODIFICATIONS MADE IN REVISED 2019 VERSION Contd …

9. HIGH STRENGTH CONCRETE (GRADE M 65 AND ABOVE) Procedure to attain HSC is similar to that of ordinary/standard strength concrete. Quality of aggregates for HSC. coarse aggregate shall be strong , sufficiently sound, free of fissures or weak planes , clean and free of surface coating and shall meet the requirement of IS:383 Parameter Requirement Impact/crushing value < 22 percent Combined Flakiness & Elongation Index < 30 percent Nominal MSA < 20 mm for up to M75 Nominal MSA Preferred 10 & 12.5 mm for M80 & above Fine Aggregate Coarser size is preferred (Zone I or Zone II)

10. HIGH STRENGTH CONCRETE (GRADE M 65 AND ABOVE) Air Content – Standard Concrete Air Content – High Strength Concrete

11. Selection of Water Content without Chemical Admixture–

12. HIGH STRENGTH CONCRETE (GRADE M 65 AND ABOVE) Selection of W/C Ratio

13. The clause has been made more elaborate to take into consideration the usage of multiple SCM/MA like FA, GGBS, SF & others for part cement replacement. It has allowed for increase in cementitious material content under such conditions, based on experience or by 10% for preliminary trial The limits of addition of FA & GGBS are kept open based on the project requirement and the quality of these materials. HSC - Calculation of Cement/Cementitious Materials Content

14. HSC - Recommended Dosage of 04 Mineral Admixtures Materials (FA, GGBS, SF & MK)

15. HSC - coarse aggregate volume per unit volume of total aggregate Reduce the estimated CA content by 5% for pumpable concrete & concrete used in congested reinforcements.

16. SELF COMPACTING CONCRETE It has been divided into different classes based on slump flow. Segregation resistance & viscosity for different areas of application Typical Range of Mix Constituents – Fines content (Particles < 125 micron) – 400-600 kg/m3 Fine Aggregate Content – 48-60 % by mass of total aggregates Water Content – 150 – 210 kg/m3

17. GUIDELINES FOR CONCRETE MIX DESIGN as per IS 10262 - 2019

18. Steps involved - At a Glance

19. STEP 1 DATA REQUIRED FOR CONCRETE MIX DESIGN Grade designation Type of cement Maximum nominal Size of Aggregate Minimum cement/cementitious material content Maximum water-cement ratio Workability Exposure conditions as per IS 456 - Table 4 & 5 Maximum temperature of concrete at the time of placing Method of transportation & placing Early age strength requirements, if required Type of aggregate Maximum Cement Content Admixture requirements & dosage

20. STEP 2 TEST DATA FOR MATERIALS Cement- Type & its specific gravity Fly ash Specific gravity (Sg F) c) Coarse Aggregates Specific Gravity (Sg CA) Water absorption Free (surface) moisture d) Fine Aggregates Specific Gravity (Sg FA) Water absorption Free (surface) moisture e) Sieve Analysis – Conforming zone f) Chemical admixture

21. GRADING LIMITS OF COARSE AGGREGATES (Table 2 of IS 383) IS Sieve (mm) % passing for Single sized aggregate of Nominal size % passing for Graded sized aggregate of Nominal size 63 mm 40 mm 20 mm 16 mm 12.5 mm 10 mm 40 mm 20 mm 16 mm 12.5 mm 80 100 - - - - - 100 - - - 63 85-100 100 - - - - - - - - 40 0-30 85-100 100 - - - 95-100 100 - - 20 0-50 0-20 85-100 100 - - 30-70 95-100 100 100 16 - - - 85-100 100 - - 90-100 - 12.5 - - - - 85-100 100 - - - 90-100 10.0 0-5 0-5 0-20 0-30 0-45 85-100 10-35 25-55 30-70 40-85 4.75 - - 0-5 0-5 0-10 0-20 0-5 0-10 0-10 0-10 2.36 - - - - 0-5 - - - -

22. GRADING LIMITS OF FINE AGGREGATES ( Table 4 of IS 383 ) IS Sieve (mm) Percentage Passing for Grading Zone I Grading Zone II Grading Zone III Grading Zone IV 10 100 100 100 100 4.75 90-100 90-100 90-100 95-100 2.36 60-95 75-100 85-100 95-100 1.18 30-70 55-90 75-100 90-100 0.006 15-34 35-59 60-79 80-100 0.003 5-20 8-30 12-40 15-50 0.0015 0-10 0-10 0-10 0-15

23. STEP 3 TARGET STRENGTH FOR CONCRETE MIX DESIGN Target Mean Strength (f’ck) = fck + (1.65 * s ) OR Target Mean Strength ( f’ck) =fck + x f’ ck – target mean compressive strength at 28 days in N/mm² f ck – characteristic compressive strength at 28 days in N/mm ² s – standard deviation, based on degree of quality control adopted at site (Ref. Table-2) X - Factor based on grade of concrete (Ref. Table -1) Note -- Adopt higher value for target mean strength

24. Grade of Concrete Value of X M10 5.0 M15 M20 5.5 M25 M30 6.5 M35 M40 M45 M50 M55 M 60 Table 1- Value of X (clause 4.2) Grade of Concrete Value of X M65 8 M70 M75 M80

25. Note - Values correspond to site control having proper Weigh batching of materials, Proper cement storage, controlled addition of water, Regular aggregate testing, Periodic strength & workability tests . Any deviations from the above Site control, the values given in the above table shall be increased by 1N/mm ² Grade of Concrete Assumed Standard Deviation (N/mm²) M10 3.5 M15 M20 4.0 M25 M30 5.0 M35 M40 M45 M50 M55 M 60 Grade of Concrete Assumed Standard Deviation (N/mm²) M65 6.0 M70 M75 M80 Table 2 - Assumed Standard Deviation (clause 4.2.1.3)

26. Note - The actual values of air content can also be adopted during mix proportioning ,if site data of similar mix is available Max. Size of Aggregate Entrapped Air ,as percentage of Vol. of Concrete 10 1.5 20 1.0 40 0.8 Table 3 – Approx. Air Content The approximate amount of entrapped air to be expected in a normal concrete can be noted using the following table Air Entrainment Meter

27. STEP 4 SELECTION OF WATER-CEMENT RATIO Select the water-cement ratio from the relationship established between strength and free water-cement ratio for the materials actually used OR select preliminary free water-cement ratio corresponding to 28 day target strength OR ; Preliminarily, find out the Maximum water-cement ratio from Table 2 (Table 5 of IS 456:2000) based on the environment exposure condition. The above water-cement ratio should be checked against the limiting water-cement ratio for the durability requirements. Adopt lower of the two values.

28. Fig.1 Relation between free water-cement ratio and 28 Compressive strength of Concrete

29. Table – 5 of IS 456 Min Cement Content, Max w/c & Min Grade of Concrete for Different Exposures with Normal Weight Aggregates of 20mm Nominal MSA Sl. No. Exposure Conditions Plain Concrete Reinforced Concrete Minimum Cement Content kg/m³ Maximum Free W/C ratio Minimum Grade of Concrete Minimum Cement Content kg/m³ Maximum Free w/c ratio Minimum Grade of Concrete 1. Mild 220 0.6 -- 300 0.55 M 20 2. Moderate 240 0.6 M 15 300 0.5 M 25 3. Severe 250 0.5 M 20 320 0.45 M 30 4. Very Severe 260 0.45 M 20 340 0.45 M 35 5. Extreme 280 0.40 M 25 360 0.4 M 40

30. Selection of Water Content

31. STEP 5 SELECTION OF WATER CONTENT Table 4 - Maximum Water Content for different Nominal MSA Nominal MSA (mm) Maximum Water Content per m 3 of Concrete for MSA of CA (kg) 10 208 20 186 4 165 Saturated surface dry aggregates Angular coarse aggregate and Slump of 50mm The above data holds good for:

32. STEP 5 SELECTION OF WATER CONTENT CORRECTIONS TO BE APPLIED ON WATER CONTENT – I) Based on aggregates : Reduction in water content Type of aggregate Reduction of water content(%) i ) Sub-angular 10 kg ii) Gravel with crushed particles 15 kg iii) Rounded gravel 20 kg II) Based on slump : Increase in water content For slump other than 50mm , Increase/Decrease the water content by 3% for every 25mm Increase/Decrease in slump . III) Use of Admixtures : Reduction in water content Water reducing admixtures – 5 to 10% Super plasticizers – 20-30%

33. STEP 6 CALCULATION OF CEMENT CONTENT Calculate the cement content per unit vol. of concrete from the water-cement ratio obtained in Step 4. Check cement content against the min. cement content for the requirements of durability under various conditions of exposure (Ref – Table 5 of IS 456 : 2000) Adopt Greater of the two values. Maximum Cement content shall be in accordance with IS 456 Clause 8.2.4.2.

34. STEP 7 ESTIMATION OF COARSE & FINE AGGREGATE PROPORTION

35. STEP 7 ESTIMATION OF COARSE & FINE AGGREGATE PROPORTION

36. STEP 7 ESTIMATION OF COARSE AGGREGATE PROPORTION CORRECTIONS TO BE APPLIED – For water ratio other than 0.50, - For every 0.05 increase in w/c , decrease the proportion of vol. of CA by 0.01 ; For every 0.05 decrease in w/c , increase the proportion of vol. of CA by 0.01. For pumpable concrete, reduce the volume of coarse aggregates by 10%

37. COMBINATION OF DIFFERENT COARSE AGGREGATES FRACTIONS Coarse aggregates of different sizes may be combined in suitable proportions so as to result in an overall grading conforming to Table2 of IS383 for particular nominal MSA ESTIMATION OF FINE AGGREGATE PROPORTION Vol. of Fine aggregates = 1 – Vol. of Coarse aggregate

38. STEP 8 MIX CALCULATIONS Vol. of the Cementitious material, water and admixture are obtained by Volume of all in aggregates = Vol. of Concrete – (Vol. of Cement +Vol . of water + Vol. of admixture) (if used) Mass of coarse aggregate = Vol. of all in aggregate X the Vol. of CA X Sp. gravity of CA X 1000 Mass of Fine aggregate = Vol. of all in aggregate X the Vol. of FA X Sp. gravity of FA X 1000 Mass of resp. materials X 1 Specific gravity of resp. materials 1000

39. The proportion of all the ingredients should be presented. Cement – Fly ash - Water – Fine aggregates – Coarse aggregates – Chemical admixtures – Note – All the aggregates considered are in saturated surface dry condition. If aggregates in any other condition are used, following allowances should be made. Allowance for free (surface) moisture contributed by the CA and FA should be considered while calculating the requirement for the mixing water. If aggregates are dry, the amount of mixing water should be increased by an amount equal to the moisture likely to be absorbed by the aggregates. Adjustments are also required to be made in the mass of aggregates. STEP 9 MIX PROPORTIONING

40. Slump of Trial Mix No.1 shall be measured, it shall be observed for segregation, bleeding and finishing properties. If the measured slump of Trail Mix No. 1 is different from the stipulated value, the water and/or admixture content shall be adjusted suitably. The mix proportion considering the above adjustment shall be recalculated keeping the free water-cement ratio at the pre-selected value. This shall be Trial Mix No.2. Two more Trial Mixes No.3 and No.4 shall be made by varying the free water-cement ratio by ± 10% of the preselected value. STEP 10 TRAIL MIXES

41. WORKED EXAMPLE

42. A1. Data Required For Mix Design Grade designation - M 30 Type of cement - OPC (IS 269 –2015) Type of mineral Admixture - Fly ash( IS 3812-2013) Maximum nominal Size of Aggregate - 20mm Exposure conditions - Moderate Minimum cement content - 300 kg/m ³ Maximum water-cement ratio - 0.50 Workability - 75 – 100 mm Type of aggregate - Crushed angular Maximum Cement Content - 450kg/m ³ Chemical Admixture - Super Plasticizer Degree of supervision - Good Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

43. A2 . Test Data for Materials Cement . Specific gravity - 3.15 b) Fly ash Specific gravity - 2.20 c) Coarse Aggregates Specific Gravity - 2.68 Water absorption - 0.5% Free (surface) moisture - Nil d) Fine Aggregates Specific Gravity - 2.66 Water absorption - 1.0% Free (surface) moisture - 2.0% Chemical Admixture . Specific Gravity - 1.1 Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

44. Sieve Analysis - COARSE AGGREGATES IS sieve size (mm) % passing % Passing of Different fractions CA1 CA2 CA1 (60%) CA2 (40%) Combined (100%) 20 93.5 100 56.1 40 96.1 10 16.5 88.2 9.9 35.3 45.2 4.75 1.2 9.40 0.7 3.70 4.70 2.36 - - - - A2 . Test Data for Materials Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

45. Sieve Analysis - FINE AGGREGATES ( confirming to Table 4 of IS 383 ) Fine Aggregates confirm to Zone II A2 . Test Data for Materials IS sieve size (mm) % passing 4.75 100 2.36 93.2 1.18 76.6 0.6 41.4 0.3 12.4 0.15 3.5 Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

46. From Table 1 , standard deviation s = 5 N/mm² Target Mean Strength (f’ck) = fck + (1.65 s) = 30 + (1.65 X 5) =38.25 N/mm2 B1 . Target Mean Strength OR Target Mean Strength( F’ck) = Fck + X =30+6.5 = 36.5 N/mm2 B2. Selection Of Water-cement Ratio From Table 2 , maximum w/c = 0.50, Based on Graph or experience adopt 0.45. 0.45< 0.50. Hence Ok. Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

47. From Table 4 , water content = 186 litre (for 20mm aggregate 50mm slump) For 100mm slump , correction needs to be applied, i.e. increase water content by 6% Water content for 100mm slump = 186 + (6/100) X 186 = 197.2 litre As superplasticizer is used, the water content can be reduced by 20% and above. Based on trials, water content reduction of 15% has been achieved. Hence, water content = 197.2 X 0.85 = 167.6 litres B3 . Selection of water content Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

48. B4 . Calculation of cement content From step 4, adopted w/c = 0.45 From step 5, water content = 167.6 litres Cement = 167.6/0.45 = 372.4 kg/m³ Check From Table 2, for ‘Moderate’ exposure condition, Minimum cement content = 300kg/m³ 372.4 kg/m³ > 300kg/m³, Hence OK. Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

49. Calculation of Fly ash content Fly ash content of total Cementitious material = 30% Qty of Fly ash content of total Cementitious material = 373 x 30% = 112 kg/ m³ Cement OPC = 373 – 112 = 261 kg/m³ Cement (OPC) = 261kg/m³ Fly ash = 112 kg/m³ Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

50. B5 . Vol. of CA and FA Content From Table-4 , volume of coarse aggregate corresponding to 20 mm size aggregates & fine aggregate (Zone II) for w/c 0.50 = 0.62 As the water cement ratio is lower by 0.05, the proportion of volume of coarse aggregates is increased by 0.01 Volume of coarse aggregates = 0.62 + 0.01 Therefore, Volume of Coarse Aggregates = 0.63 Volume of Fine Aggregates = 1 – 0.63 = 0.37 Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

51. B6 . Estimation of FA Proportion Volume of Concrete = 1m ³ Volume of Entrapped Air in Wet Concrete = 0.01 m3 Volume of Cement = ( 261/3.15) x (1/1000) = 0.082m ³ Volume of Fly ash = (112/2.2) x (1/1000 ) = 0.0509 m3 Volume of water = (167.6/1) X ( 1/1000) = 0.168m ³ Volume of Chemical admixture = (3.72/1.1) X (1/1000 ) = 0.0033m3 Volume of all in aggregates = [1 – 0.01 - ( 0.082 +0.0509 + 0.168 + 0.0032)] = 0.686 m³ Vol. of the Cementitious material and water are obtained by Mass of resp. materials X 1 Specific gravity of resp. materials 1000 Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

52. B6 . Estimation of FA Proportion contd…. v) Mass of Coarse aggregates = 0.686 X 0.63 X 2.68 X 1000 = 1158.0 kg. vi) Mass of Fine aggregates = 0.686 X 0.37 X 2.66 X 1000 = 675.0 kg. B7. Mix Proportion ( for 1m ³ ) Cement = 261.0kg Fly ash = 112.0 kg Water = 167.0kg Fine aggregates = 675.0 kg Coarse aggregates = 1158.0 kg Chemical Admixture ( 1% of Total mass of cementations ) = 3.72kg w/c = 0.45 Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

53. B7 . Mix Proportion (for 1m³) contd…. Corrections applied for water content and mass of aggregates considering the Water absorption & Free moisture: Water absorption of CA is 0.5%, Free Moisture in FA is 2%. I ) Extra Quantity of water to be added for absorption in case of CA at 0.5% = (0.5/100) X 1158.0 = 5.8 kg.   II) Extra Quantity of water to be added for absorption in case of F A at 1.0% = ( 1 /100 ) X 675.0 = 6.75 kg III) Quantity of water to be deducted for free moisture in FA at 2% = (2/100) X 675.0 = 13.50 kg.   Actual water required = 167.0 + 5.8 + 6.75 – 13.50 = 166.0 kg Actual sand required = 675 – 6.75+ 13.50 = 682 kg. Actual CA required = 1158.0 – 5.8 = 1152.0kg. Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

54. B8. Actual Quantities for Trial No. 1 Cement 265 kg/ m³ Fly ash 110 kg/ m³ Sand 682 kg/ m³ Coarse Aggregates 1152 kg/ m³ Water 166 kg/ m³ Chemical Admixture 3.72 Kg/m ³ Example 1 : MIX PROPORTIONING FOR CONCRETE OF GRADE M30

55. Trial Mix & Measure A Slump Workability

56. Good Construction Practices :- ;: ;-

57. Homogeneity and cohesiveness of concrete Compaction of Concrete Control W/C Raito Superior finishing of slabs/wall etc. No honeycombing Reduce cracks Durability of Structure Benefits of Good Construction Practices :-