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(Fourth Revised Edition)
CONCRET
E MIX
DESIGN
N.Pokharel
1
INTRODUCTION 1
AMERICAN CONCRETE INSTITUTE (ACI) METHOD 4
GENERAL 5
LIMITATION ACI METHOD 5
REQUIRED PARAMETERS OF INGREDI...
INTRODUCTION
1. American Concrete Institute (ACI)
2. High Strength Mix
Cement concrete is an artificial rock which can be ...
1. Cement:
a) Portland cement, of possibly 53 grade
b) Specific gravity 3.15
2. Fine Aggregate
a) Required size and well-g...
g) Compacted density (Kg/m3
):
Aggregate
Sp.gr. 2.62 - 2.65 2.66 - 2.69
50 mm
16001600
17001750 1800
1650 1400
Crushed roc...
American Concrete
Institute (ACI)
METHOD
6
GENERAL
F
F
F
LIMITATION ACI METHOD
F It is better to design a concrete mix only up to 35 MPa of plastic state.
F
F
REQUIR...
C. COARSE AGGREGATE
1. Gradation (Sieve Analysis)
2. Dry Rodded Unit Weight
3. Specific Gravity (SSD Bulk)
4. Absorption
D...
DESIGN GUIDE LINE
F
F
Percentage of
recommended average total air content.
F
3.5 3.08.0 7.0 6.0 5.0
112 to 56
56 to 28
4.5...
F
0.53 #
Exposure Condition *
The exposure condition of structure may be affected by the climatic
condition, chemicals in ...
F
Where,
VA = apparent vol. of solid particles per unit volume of concrete
g1 = used specific gravity
VD = Vol. of dry rod...
F
10 12 20 25 40
177 168 158 148 137
188 182 168 158 148
196 192 177 168 158
206 196 182 177 162
226 217 203 192 177
240 2...
F
Table : 7 Zone of Limit of Concrete Aggregate as adpoted by ACI
(ASTM:C-33)
The aggregates to be used in concrete mix sh...
F
FM = 284.40 /100 = 2.84
SUMMARY OF DESIGN PROCEDURE
F
F
F
F
F
F
F
F
F
F
F
% of Retained
Now prepare three sample after v...
Mix Design Data Sheet
TRIAL MIX TM-….… A
Project A1
Location A2
Structure A3
Member A4
Concrete Class A5
Type and Brand of...
Design Steps
TRIAL MIX TM-….… A
Weight of water Required (Kg/m3
) B1
Weight of Coarse Aggregate Required (Kg/m3) B2
Weight...
Design Steps
TRIAL MIX TM-….… B
Weight of water Required (Kg/m3
) C1
Weight of Coarse Aggregate Required (Kg/m3) C2
Weight...
Design Steps
TRIAL MIX TM-….… C
Weight of water Required (Kg/m3
) D1
Weight of Coarse Aggregate Required (Kg/m3) D2
Weight...
Compressive Strength Test of Sample
TRIAL MIX TM-….… A
"
"
"
"
"
TRIAL MIX TM-….… B
"
"
"
"
"
TRIAL MIX TM-….… C
"
"
"
"
"...
Graphical Determination of Required W/C Ratio
Summary of Designed Mix
TRIAL MIX TM-….… B
TRIAL MIX TM-….… A
TRIAL MIX TM-…...
High Strength Mix
METHOD
21
GENERAL
FEATURE DESIGN
F
F
F
In general, only a natural sand is needed for use of fine aggregate
because high strength are...
F
F
LIMITATION OF HIGH STRENGTH DESIGN
F
F
F Graphical tables are used instead of analytical formulas or so on.
F
Combined...
REQUIRED PARAMETERS OF INGREDIENTS
A. CEMENT
1. Grade and type
2. Specific Gravity
B. FINE AGGREGATE
1. Gradation (Sieve A...
D. WATER
1. Chemical content(free of salt and alkalis)
2. Turbidity (potable or clear)
DESIGN PROCEDURE
F
F
F
F
F
Find out...
EQUIPMENT AND APPARATUS
For preparing the sample following euipments are needed:
1. 6 nos. Cylinder or Cube Mould 4. Scoop...
3.0 2.4 3.3 2.9
3.8 2.5 3.2 4.0 2.6 3.6 2.3
4.5 3.0 2.5 3.9 2.6 4.6 3.2 2.6 4.2 2.8 2.3
5.2 3.5 3.0 2.5 4.6 3.1 2.6 5.2 3....
2.6 2.9 2.5
3.4 2.2 2.8 3.6 2.4 3.2
4.1 2.7 2.3 3.5 2.4 4.3 2.9 2.4 3.9 2.5
4.8 3.2 2.8 2.3 4.2 2.9 2.4 4.9 3.4 2.9 2.4 4....
Mix Design Data Sheet
TRIAL MIX: TM - …. A
Project A0
Location A1
Structure A2
Member A3
Concrete Class A4
Type and Brand ...
Design Steps
TRIAL MIX: TM - A
A : Mix Proportion by Weight (with reference to cement)
1 Cement B1
2 Water B2
3 Fine Aggre...
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Concrete Mix Design Manual

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Concrete Mix Design Manual

  1. 1. (Fourth Revised Edition) CONCRET E MIX DESIGN N.Pokharel 1
  2. 2. INTRODUCTION 1 AMERICAN CONCRETE INSTITUTE (ACI) METHOD 4 GENERAL 5 LIMITATION ACI METHOD 5 REQUIRED PARAMETERS OF INGREDIENTS 5 EQUIPMENT AND APPARATUS 6 DESIGN GUIDE LINE 7 SUMMARY OF DESIGN PROCEDURE 12 MIX DESIGN DATA SHEET 13 DESIGN STEPS 14 COMPRESSIVE STRENGTH TEST OF SAMPLE 17 GRAPHICAL DETERMINATION OF REQUIRED W/C RATIO 18 HIGH STRENGTH MIX METHOD 19 GENERAL 20 FEATURE OF DESIGN 20 LIMITATION OF HIGH STRENGTH DESIGN 21 REQUIRED PARAMETERS OF INGREDIENTS 22 DESIGN PROCEDURE 23 EQUIPMENT AND APPARATUS 24 MIX DESIGN DATA SHEET 27 DESIGN STEPS 28 Contents 2
  3. 3. INTRODUCTION 1. American Concrete Institute (ACI) 2. High Strength Mix Cement concrete is an artificial rock which can be made of required size, shape, and strength for the structure in construction work. It is the most widely used construction material and is very hard to find its substitution . Technologists may select this construction material as their requirement such as strength, permanance, durability, impermeability, fire- resistance, abrasion resintance etc. Regarding these required properties of concrete, it is very important to determine the proportion as well as quality of its constituents. Determining process of selecting suitable ingredients, its proportion, producing minimum strength and durability as economically as possible is called mix design. In Nepal, still we adopt the arbitrary proportional ratio method in many organizations of HMG departments, municipalities, private buildings and other small scaled projects. But most of the large scaled foreign aid projects can not ignore the necessity of mix design of the concrete for precise supervision. The arbitrary proportinal method may always not govern the true proportion of ingredients and cause segregation, bleeding, uneconomic and weaker or over strength. People are not conscious to hire Basic concept of mix design prevails on the relationship between two essential ingredients i.e. aggregates and paste. Paste is not termed as solution of cement in water, but the suspension of cement particles. Hence the degree of dilution of paste may affect workability and strength of the concrete. The more dilute the paste, the greater the spacing between cement particles and thus the weaker will be ultimate paste structure. It is therefore helpful to consider more closely the structure of the paste. It is important that as little paste as possible should be used and here lies the importance of grading of aggregates. Excess of paste cause high cost, greater shrinkage, greater susceptibility to percolation of water and therefore attack by aggressive waters and weathering action. This is achieved by minimising the voids by well gradation. There are several methods of mix design to adopt, but here we describe only two of them in detail which are more effective and viable in the contest of Nepal. Most of the renowned projects and agencies of Nepal have been adopting these two mix-design methods widely as per their requisites of the concrete materials. These methods are - 3
  4. 4. 1. Cement: a) Portland cement, of possibly 53 grade b) Specific gravity 3.15 2. Fine Aggregate a) Required size and well-graded and washed. b) Saturated surface dry condition (SSD) c) Very less weathering, alluvial (glacier) blueish grey: Specific gravity 2.65 to 2.67 Absorption 1.0% d) Less weathering, alluvial deposit (perennial river), yellowish grey: Specific gravity 2.62 to 2.64 Absorption 1.5% e) Less weathering, alluvial deposit (stream), pale yellow: Specific gravity 2.59 to 2.61 Absorption 2.0% f) Washed crushed rock: Specific gravity 2.62 to 2.65 Absorption 1.5% g) Fineness modulus (FM) coarser 3.1, moderate 2.9, fine 2.6, very fine 2.3 3. coarse Aggregate a) Required size and well-graded and washed. b) Saturated surface dry condition (SSD) c) Alluvial / glacier (fresh deposit): Specific gravity 2.67 to 2.72 Absorption 0.3% d) Alluvial / common perennial river (fresh deposit): Specific gravity 2.62 to 2.66 Absorption 0.5% e) Alluvial (loose conglomerate): Specific gravity 2.62 to 2.65 Absorption 0.7% f) Washed crushed rock (stream), Specific gravity 2.62 to 2.65 Absorption 0.7% a technician to conduct the supervision and rely on a head mason who will be contractor of their private construction. In Terai region of Nepal, most of these masons have tendency of using more sand with large size coarse aggregate and less sand with small size aggregate which is absolutely wrong approach . Due this reason, people find their construction defective after all. Regarding these common problems all over the country, it is highly necessary to follow the technical way of construction wheather it's small or huge construction. Possibly, it is needed to conduct the test of concrete materials to obtain true design parameters. Otherwise adopt in design these parameters for concrete materials, if conducting the test is not possible. These parameters are here tabulated below according to practice and records. 4
  5. 5. g) Compacted density (Kg/m3 ): Aggregate Sp.gr. 2.62 - 2.65 2.66 - 2.69 50 mm 16001600 17001750 1800 1650 1400 Crushed rock: 1650 1650 1550 From the above statement, a technical person can easily decide the nearest true properties of concrete material according to its possession regarding location, appearance etc. After conforming these data tentatively, here we can proceed the mix design calculation as per our requirements. It may give more accurate proportion and workability than the arbitrary ratio gives. If little bit difference in volume or workability is found, it may be adjusted very easily. 1850 1750 2.62 - 2.65 2.66 - 2.69 2.70 - 2.72 1450 1500 1700 1550 38 mm 1750 10 mm 20 mm 1450 1800 1600 Screened gravel 5
  6. 6. American Concrete Institute (ACI) METHOD 6
  7. 7. GENERAL F F F LIMITATION ACI METHOD F It is better to design a concrete mix only up to 35 MPa of plastic state. F F REQUIRED PARAMETERS OF INGREDIENTS A. CEMENT 1. Grade and type as ACI - classification 2. Specific Gravity B. FINE AGGREGATE 1. Gradation (Sieve Analysis) 2. Fineness Modulus (FM i.e. 2.4 to 3.1preferable) 3. Specific Gravity (SSD Bulk) 4. Absorption Type-I, non air-entraining (OPC) as per ASTM/C-150, Specific Gravity of 3.15 Coarse aggregate:- Gradation as per ASTM/C-33, Specific Gravity of 2.68, Absorption of 0.5%. Fine Aggregate :- Gradation as per ASTM/C-33, Specific Gravity of 2.64, Absorption of 0.7%, FM of 2.8 The American Concrete Institute (ACI) has recommended an efficient procedure of concrete mix design considering more economical use of locally avilable materials to produce desirable workability, durability and strength. The ACI method is able to produce concretes from very stiff to fluid state workability as it is required in different conditions.The design tables incorporating the basic relationships between the parameters, are useful in selecting optimum combinations of the ingredients of non air- entrained or air-entrained concrete mixes. The following design criteria are assumed in formulating the design tables: Though the specific gravity of coarse aggregate is taken 2.68 in this ACI manual but if it is different see footnote of table-4. It is important to note that the mix design tables serve as a guide in selecting proportions and suitable minor adjustments should be effected in the field for any departures in quality of aggregates and type of cement used. Before starting to design a concrete mix, it is very much important to have all informations about concrete ingredients i.e physical test reports. These physical parameters may be obtained by own laboratory test or by the manufacturer. Basicaly for the design mix, the following parameters should be available in the time. 7
  8. 8. C. COARSE AGGREGATE 1. Gradation (Sieve Analysis) 2. Dry Rodded Unit Weight 3. Specific Gravity (SSD Bulk) 4. Absorption D. WATER 1. Chemical content(free of salt and alkalies) 2. Turbidity (potable or clear) EQUIPMENT AND APPARATUS A. SLUMP TEST 2. Mixer or mixing pan 1. Slump cone 3. Triple beam balance (1 g.) 2. Base plate 4. Scoop 3. Tamping rod 5. Straight edge 4. Graduated scale 6. Tamping rod or 5. Straight edge 7. Vibrator plate 6. Mixer (1 cft.) or 8. Rubber mallet 7. Mixing pan with shovel 9. Weighing containers 8. Scoop 10. Thermometer 9. Triple beam balance (1 g.) C. STRENGTH TEST 10. Weighing containers 1. Compressive St. machine B. SAMPLE PREPARATION 2. Triple beam balance (1 g.) 1. 6 nos. cylinder or cube mould 3. Rubber sheet To perform a mix design, the following equipment or apparatuses must be available in advance: 10 15 20 25 30 35 40 45 50 0.36 0.40 0.44 0.48 0.52 0.56 0.60 0.64 0.68 0.72 0.76 0.80 CYLINDERSTRENGTHIN28DAYS(MPa) WATER CEMENT RATIO fig.- 1 RELATIONSHIP OF W/C RATIO TO STRENGTH Non Air Entarined Mix Air Entarined Mix 8
  9. 9. DESIGN GUIDE LINE F F Percentage of recommended average total air content. F 3.5 3.08.0 7.0 6.0 5.0 112 to 56 56 to 28 4.5 4.0 Drop Table Revolutions 160 170 175 185 180 190 135 - 150 160 155 165 165 160 145 140 135 120 80 - 100 150 - 180 180 175 190 205 200 215 20 - 50 Maximum Size of Coarse Aggregates (mm) Air Entrained Concrete 20 25 40 50 0.3 0.2 percentage amount of entrapped air in non air entrained concrete. Approximate 145 160 170 200 210 180 195 205 80 - 100 155 170 180 125 140 - 175 240 230150 - 180 225 215 Table : 1 Approximate Mixing of Water (Kg/m 3 of Concrete) Requirements for Different Slumps and Maximum Size of Aggregates Slump (mm) 185 150 0.53 2 1.5 12.5 Non Air Entrained Concrete 10 12.5 205 200 185 16020 - 50 70 3 to 0 - 0.90 0.95 Compacting Factor - 0.70 0.75 0.85 Slump 25 - 50 75 - 100 150 - 175 Vebe (Sec.) 32 to 18 18 to 10 10 to 5 5 to 3 Plastic Flowing (mm) 0 - 25 - - Extremely dry Very stiff Stiff Stiff plastic Firstly, to know the water cement ratio of concrete mix, find out it by coinciding the required designed strength (i.e. minimum required strength plus strength for safety factor as specified or assumed) to the appropriate graph line mentioned in figure -1 above. To know the quantity of water for 1 m3 of fresh concrete made in screened river gravel, find out that required quantity with regarding the desirable workability (slump) mentioned in table -1 below. This table does not entertain crushed aggregate. The way of inspection and testing of consistency or workability of concrete may differ as the specification quotes in different projects, so compare the following consistency as it requires. 28 to 14 14 to 7 7 - Table : 2 Comparison of Consistency Measurements by Various Methods Consistency Description 9
  10. 10. F 0.53 # Exposure Condition * The exposure condition of structure may be affected by the climatic condition, chemicals in contact (such as sulphate, salt, water etc) or air. It means that durability of concrete should be considered as its exposure condition that governs the strength of concrete (required w/c ratio will be selected from the table-3 below). Table : 3 Maximum Permissible Water Cement Ratios for Different Types of Structures and Degrees of Exposure Type of structures At the water line or with in the range of fluctuating water level or spray Severe wide range in temperature, or frequent alternations of freezing and thawing (air entrained concrete only) In air At the water line or with in the range of fluctuating water level or spray In fresh water In sea water or in contact with sulphates1 Mild temperature rarely below freezing, or rainy, or aid. In sea water or in contact with sulphates1 In fresh water In air 1 Soil or ground water containing sulphate concentrations of more than 3.2%. **When sulphate resisting cement (as per ACI type-V) is used, maximum water/cement ratio may be increased by 0.13 litres per bag. # Water/cement ratio should be selected on basis of strength workability requirements. 0.39 Concrete which will later be protected by enclosure or backfill what which may be exposed to freezing and thawing for several years before such protection is offered. 0.53 - - # - - # - # *Air entrained concrete concrete should be used under all conditions involving severe exposure and may be used under mild exposure conditions to improve workability of the mixture. Concrete protected from weather, interiors of buildings, concrete below ground. - - - 0.44 Concrete slabs laid on the ground. -- - - Concrete deposited by tremie under water - 0.44 0.44 0.44** Exterior portions of heavy (mass) sections. 0.57 0.48 0.44 # 0.53 0.44** - 0.44 0.53 0.48 # 0.53 0.390.44 Thin sections, such as railings, curbs, sills, ledges, ornamental or architectural concrete, reinforced piles, pipes and all sections with less than 25 mm. Concrete cover reinforcing. Moderate sections, such as retaining walls, abutments, piers, girders, beams. 0.53 0.48 0.44** 0.48 10
  11. 11. F Where, VA = apparent vol. of solid particles per unit volume of concrete g1 = used specific gravity VD = Vol. of dry rodded agg. per unit volume of concrete F for example: VC = f x VA = 1.15 x 0.62 = 0.71 Where, VC = corrected vol. of aggregate in per unit vol. of stiff concrete f = multiplying factor from table-5 (next page) VA = apparent vol. of solid particles per unit volume of concrete from table-4 0.65 0.63 0.6620 0.60 0.58 0.5912.5 0.53 0.51 0.5010 0.44 0.42 Table : 4 Volume of Dry Rodded Coarse Aggregates per Unit Volume of Concrete (V D ) only for Plastic Consistency Maximum Size of Coarse Aggregate 2.60 3.00 3.202.802.40 Fineness Modulus (FM) of Sand Find out the volume of aggregate for per unit volume of concrete with respect to the fineness modulus of sand and nominal maximum size of aggregate. The value not given in following table will be determined by interpolation of given value which are only for the particular aggregate with specific gravity of 2.68. If our specific gravity is different then, see the note of table 4. 0.70 0.68 50 0.76 0.72 0.70 0.74 0.72 0.74 40 To determine the exact volume of coarse aggregate in per unit volume of concrete in non-plastic consistency (i.e. in stiff condition), select the appropriate multiplying factor (f) listed below to the volume mentioned in table-4. For example, see note# of table-5 in next page. 0.77 0.83 Note: The volume of dry rodded coarse aggregate recommended in above table, applies to the aggregate of the given specific gravity g which in this case is 2.68. If the aggregate used has a specific gravity g 1 , the volume of coarse aggregates specified in the table should be multiplied by the ratio (g 1 /g ) to account for gross apparent volume (VA) of solid particles. i.e. V A = g 1 /2.68xV D 0.75 0.73 150 0.85 0.71 0.76 0.78 0.81 0.7970 25 0.46 0.55 0.62 0.67 0.48 0.57 0.64 0.69 0.81 0.790.87 If it is to prepare a concrete mix with a slump (0 - 25 mm) and 20 mm aggregate in a sand with FM 2.8 then the corrected volume of coarse aggregate per unit volume of 11
  12. 12. F 10 12 20 25 40 177 168 158 148 137 188 182 168 158 148 196 192 177 168 158 206 196 182 177 162 226 217 203 192 177 240 226 212 203 188 3.0 2.5 2.0 1.5 1.0 158 148 137 133 123 168 158 148 137 133 177 168 158 148 137 182 177 162 152 143 203 192 177 168 158 212 203 188 177 168 8.0 7.0 6.0 5.0 4.5 Percentage of approximate amount of entrapped air in non-air - entrained concrete, Air-Entrained Concrete 78 83 88 106 0.91 0.95 Stiff plastic 92 Plastic Flowing 75 - 100 150 - 175 100 - 0.70 0.75 0.85 Non - Air-Entrained Concrete Workability - 112 - 56 56 - 28 28 - 14 14 - 7 7 - 18 to 10 10 to 5 5 to 3 3 to 0 Factors for Maximum Size of Coarse Aggregate (mm) 1.09 1 11 12.5 1.7 Water, Kg. Per m3 for indicated maximum size of C. A. (mm) Relative Water content (%) 1.06 1 1 40 1.3 1.25 1.21.15 25 1.4 1.25 1.15 Consistence 1 1.45 1.3 10 1.9 1.6 1.35 20 1.45 1.3 1.08 1.06 Drop Table Revolutions Compacting Factor Fluid 1 0.97 Plastic (Reference) 0.98 1.04 Table : 6 Approximate Mixing of Water (Kg/m 3 of Concrete) Required for Different Consistencies and Maximum Size of Aggregates * Stiff Very stiff Extremely dry Extremely dry 1 - Slump (mm) Vebe, (sec.) Stiff plastic - 0 - 25 25 - 50 Very Stiff Stiff Table:5 Factor ( f ) to Applied to the Volume of Coarse Aggregate Calculated on the Basis of Table:4, for Mixes of Consistence Other than Plastic 32 to 18 To know the quantity of water for 1 m3 of fresh concrete made in crushed aggregate, find out that required quantity with regarding the desirable workability (slump) mentioned in table -6 below. This table does not entertain the aggregate produced by screened river gravel. Extremely dry - 32 to 18 112 - 56 - 78 Stiff 0 - 25 10 to 5 28 - 14 Very Stiff - 18 to 10 56 - 28 0.70 83 0.75 88 0.85 92 0.91 100 Stiff plastic 25 - 50 Plastic 75 - 100 3 to 0 7 5 to 3 14 - 7 0.95 106 Recommended average total air content, percent (%) Flowing 150 - 175 - - * These quantities of mixing water are use in computing factors for trial batches. They are for reasonably well- shaped angular coarse aggregates graded within limits of accepted specifications. If more water is required than shown, the cement factor, estimated from these quantities, should be increased to maintain desired water- cement ratio, except as otherwise indicated by laboratory tests for strength. 12
  13. 13. F Table : 7 Zone of Limit of Concrete Aggregate as adpoted by ACI (ASTM:C-33) The aggregates to be used in concrete mix should fall with in the zone of limit envelope for each NMSA mentioned below. 4.75~25 9.5~25 95 ~ 100 37.5~90 0~5 2.36~9.5 4.75~12.5 4.75~19 9.5~19 0 ~ 5 4.75~50 25~50 37.5~63 0.15 2.36 1.18 0.6 0.3 0.6 0.3 0.15 100 Sieve Size (mm) 9.5 4.75 0 ~ 5 9.5 4.75 2.36 1.18 2 ~ 10 100 90 ~ 100 40 ~ 85 10 ~ 40 0 ~ 15 Sieve Size (mm) 100 90 75 63 50 37.5 25 19 12.5 12.5~25 4.75~37.5 80 ~ 100 50 ~ 85 25 ~ 60 10 ~ 30 100 100 90 ~ 100 40 ~ 70 100 85 ~ 100 10 ~ 30 0 ~ 10 0 ~ 5 0 ~ 15 0 ~ 10 0 ~ 5 20 ~ 55 100 90 ~ 100 20 ~ 55 100 90 ~ 100 100 0 ~ 15 0 ~ 5 100 95 ~ 100 25 ~ 60 0 ~ 10 0 ~ 5 0 ~ 5 90 ~ 100 20 ~ 55 0 ~ 10 95 ~ 100 35 ~ 70 0 ~ 5 90 75 19~37.5 63 50 37.5 25 19 12.5 10 ~ 30 0 ~ 5 100 0 ~ 5 0 ~ 15 100 90 ~ 100 20 ~ 55 100 95 ~ 100 100 90 ~ 100 35 ~ 70 0 ~ 15 0 ~ 510 ~ 30 35 ~ 70 0 ~ 15 0 ~ 5 100 90 ~ 100 25 ~ 60 100 90 ~ 100 0 ~ 5 0 ~ 15 35 ~ 70 13
  14. 14. F FM = 284.40 /100 = 2.84 SUMMARY OF DESIGN PROCEDURE F F F F F F F F F F F % of Retained Now prepare three sample after varying W/C ratio with 5% more & 5% less but keeping the quantity of water same in two of them. Test these three sample in specified time and plot graph strength vs W/C ratio. Here it is determined the actual W/C ratio required for min. design strength graphically. % of Passing Similarly, multiplying the dry rodded density to volume required as per table-4, find out the quantity of coarse aggregate required. Determine the min. design strength including safety factor for site. 25 to 60 10 to 30 2 to 10 Find the fineness modulus (FM) of sand from the sieve analysis report prepared in laboratory same as demonstrated in table-7 below. Now calucate the absolute volume of concrete by using the respective specific gravity of materials excluding sand. Find out the W/C ratio as per strength consideration using fig.-1 or as per durability in exposer consideration table-3, whichever is lower. Determine the quantity of water required and percentage of air entraining using table-1 or table-6 as the coarse aggregate is used. Find out the volume of coarse aggregate using table-4 and table-5, with respect to FM value as well as specific gravity of sand. Thus find out the quantity of cement having value of W/C ratio and water required for 1 m3 of concrete. 50 to 85 6.414.2 Table : 8 Example , Determination of Fineness Modulus of Fine Aggregate (Sand) from Sieve Analysis Report ACI Specification Limit (ASTM:C- 33) 95 to 100 80 to 100 % cum. Retained 0.0 8.5 Mass of Retained (gms) 0.0 60.0 - 100.0 91.5 63.1 20.6 2.8 - 97.2 100.0 42.6 3.5 2.820.0 200.0 300.0 100.0 25.0 36.9 0.0 8.5 28.4 79.4 93.6 No # 8 2.36 No # 16 No # 30 0.60 No # 50 0.30 Sieve Size BS mm No # 100 0.15 Pan 1.18 No # 4 4.75 TOTAL 705 284.4 Collect the all the properties of concrete materials by conducting necessary tests. Then subtracting that absolute volume in 1 m3 volume, the remaining value will be determined as the volume of sand which is converted in weight by using the specific gravity of sand. 14
  15. 15. Mix Design Data Sheet TRIAL MIX TM-….… A Project A1 Location A2 Structure A3 Member A4 Concrete Class A5 Type and Brand of Cement A6 Source of Fine Aggregate A7 Type of Coarse Aggregate A8 Source of Coarse Aggregate A9 Specific Gravity of Cement A10 Specific Gravity of Fine Aggregate A11 Fineness Modulus (FM) of F.A. (as determined in table-7) A12 Nominal Max. Size of Coarse Aggregate (mm) A13 Specific Gravity of Coarse Aggregate A14 Rodded Unit Weight of Coarse Aggregate (Kg/m3) A15 Minimum Cylinder Strength Required # (MPa) A16 Percentage of Safety Factor Specified (%) A17 Net Design Cylinder Strength (MPa) A18 Water Cement Ratio (wc1) - [whichever is lower below] A20 Strength Consideration (fig.-1) or Durability Consideration (table-2 ) Desirable Workability (Slump) (mm) A21 *Required Weight of Water (table-1or 6) (Kg/m3) A22 *Entrained Air in Concrete (table-1 or 6) (%) A23 (* If the coarse aggregate is crushed rock i.e angular shape, use table-6) Volume of Coarse Aggregate Required (table-4) A24 TRIAL MIX TM-….… B Water Cement Ratio (wc2) - [10% more than specified] A25 TRIAL MIX TM-….… C Water Cement Ratio (wc3) - [10% lesser than specified] A26 A16 + (A17/100)xA16 ( # If cube strength is required, select 80% of cylinder strength above i.e Cube Strenght = 1.2 x Cyl. Strength ) A20 + 0.10 x A20 A20 - 0.10 x A20 15
  16. 16. Design Steps TRIAL MIX TM-….… A Weight of water Required (Kg/m3 ) B1 Weight of Coarse Aggregate Required (Kg/m3) B2 Weight of Cement Required (Kg/m3) B3 Solid Volume of Cement in Concrete (cc) B4 Solid Volume of Water in Concrete (cc) B5 Solid Volume of Coarse Aggregate in Concrete (cc) B6 Volume of Entrained Air in Concrete (cc) B7 Total Volume of Ingredients (except F. Agg.) (cc) B8 Required Volume of Fine Aggregate in Concrete (cc) B9 Weight of Fine Aggregate Required (Kg/m3) B10 ESTIMATED BATCH QUANTITY Cement (Kg) Water (Kg) Fine Aggregate (Kg) Coarse Aggregate (Kg) Density of Fresh Concrete (Kg/m3 ) 0.007 x B1 For 1 m3 Volume Ingredients NOTE: Here, check the slump of this TRIAL-A. If the desirable slump range is not obtained, recalculate by increasing or decreasing the weight of water by 5% again and again until the slump is maintained but keeping the W/C ratio same. After maintaining the desirable slump, prepare six nos. of sample (cylinder or else) for strength test and then proceed to TRIAL -B. 0.04 x B2B2 0.04 x B10B10 B3+B1+B10+B2 0.007 x B2 0.007 x B10 40 Litres for Lab. Sample B1 7 Litres for Slump Test 0.007 x B3 0.04 x B1 0.04 x B3B3 B3 x 1000 / A10 A23 /100 x 1000000 B4+ B5+ B6+ B7 1000000 - B8 B9 x A11 /1000 B2 x 1000 / A14 A24 x A15 A22 B1 / A20 B1 x 1000 16
  17. 17. Design Steps TRIAL MIX TM-….… B Weight of water Required (Kg/m3 ) C1 Weight of Coarse Aggregate Required (Kg/m3) C2 Weight of Cement Required (Kg/m3) C3 Solid Volume of Cement in Concrete (cc) C4 Solid Volume of Water in Concrete (cc) C5 Solid Volume of Coarse Aggregate in Concrete (cc) C6 Volume of Entrained Air in Concrete (cc) C7 Total Volume of Ingredients (except F. Agg.) (cc) C8 Required Volume of Fine Aggregate in Concrete (cc) C9 Weight of Fine Aggregate Required (Kg/m3) C10 ESTIMATED BATCH QUANTITY Cement (Kg) Water (Kg) Fine Aggregate (Kg) Coarse Aggregate (Kg) Density of Fresh Concrete (Kg/m3 ) Note: Prepare minimum 6 nos. of samples (cube or cylinder). 3 nos for 7 days and 3 nos. for 28 days. C1 / A25 C3 x 1000 / A10 A23 /100 x 1000000 C9 x A11 /1000 0.04 x C1 A22 Ingredients For 1 m3 Volume 7 Litres for Slump Test 40 Litres for Lab. Sample C3 0.007 x C3 0.04 x C3 C4+ C5+ C6+ C7 1000000 - C8 C1 x 1000 C2 x 1000 / A14 A24 x A15 C10 0.007 x C10 0.04 x C10 C1 0.007 x C1 C3+C1+C10+C2 C2 0.007 x C2 0.04 x C2 17
  18. 18. Design Steps TRIAL MIX TM-….… C Weight of water Required (Kg/m3 ) D1 Weight of Coarse Aggregate Required (Kg/m3) D2 Weight of Cement Required (Kg/m3) D3 Solid Volume of Cement in Concrete (cc) D4 Solid Volume of Water in Concrete (cc) D5 Solid Volume of Coarse Aggregate in Concrete (cc) D6 Volume of Entrained Air in Concrete (cc) D7 Total Volume of Ingredients (except F. Agg.) (cc) D8 Required Volume of Fine Aggregate in Concrete (cc) D9 Weight of Fine Aggregate Required (Kg/m3) D10 ESTIMATED BATCH QUANTITY Cement (Kg) Water (Kg) Fine Aggregate (Kg) Coarse Aggregate (Kg) Density of Fresh Concrete (Kg/m3 ) Note: Prepare minimum 6 nos. of samples (cube or cylinder). 3 nos for 7 days and 3 nos. for 28 days. D2 0.007 x D2 0.04 x D2 D4+ D5+ D6+ D7 1000000 - D8 D9 x A11 /1000 Ingredients For 1 m3 Volume 7 Litres for Slump Test D3+D1+D10+D2 D10 0.007 x D10 0.04 x D10 D1 0.007 x D1 0.04 x D1 40 Litres for Lab. Sample A22 A24 x A15 D1 / A26 D3 x 1000 / A10 D1 x 1000 D2 x 1000 / A14 A23 /100 x 1000000 D3 0.007 x D3 0.04 x D3 18
  19. 19. Compressive Strength Test of Sample TRIAL MIX TM-….… A " " " " " TRIAL MIX TM-….… B " " " " " TRIAL MIX TM-….… C " " " " " " s6 = p6 / a W/CRatio Compressive Load (N) p1 p2 p3 p4 p5 p6 X28=(S1+S2+S3)/35 28 " s5 = p5 / a 6 28 4 28 " s4 = p4 / a 3 7 " Age of Sample (day) W/CRatio Compressive Load (N) s3 = p3 / a Sectional Area (mm2 ) Compressive Strength (Mpa) 28 p6 s4 = p4 / a s2 = p2 / a 7 " 7 Age of Sample (day) p4 p5 Sectional Area (mm2 ) p2 " " s6 = p6 / a 1 7 6 Remarks 1 7 a s1 = p1 / a X7=(S1+S2+S3)/32 Sample No. s2 = p2 / a X28=(S1+S2+S3)/3 4 28 " Average Strength (Mpa) 5 28 " s5 = p5 / a p3 Average Strength (Mpa) Remarks X7=(S1+S2+S3)/3 3 7 " s3 = p3 / a Sample No. " s6 = p6 / ap6 X28=(S1+S2+S3)/3 2 Compressive Strength (Mpa) p1 a s1 = p1 / a p4 " s4 = p4 / a p3 " s5 = p5 / ap5 2 Sample No. Age of Sample (day) W/CRatio Compressive Load (N) 7 p1 7 p2 Remarks " 1 X7=(S1+S2+S3)/3 Sectional Area (mm2 ) Compressive Strength (Mpa) " s3 = p3 / a a 5 6 7 28 28 28 3 4 s1 = p1 / a Average Strength (Mpa) s2 = p2 / a 19
  20. 20. Graphical Determination of Required W/C Ratio Summary of Designed Mix TRIAL MIX TM-….… B TRIAL MIX TM-….… A TRIAL MIX TM-….… C TRIAL MIX TM-11, B TRIAL MIX TM-11, A TRIAL MIX TM-11, C Mix Design W/C Ratio 7 Days Strength (Mpa) 28 Days Strength (Mpa) as per design Remarks W/C2 w/c=5% more W/C Ratio 7 Days Strength (Mpa) 28 Days Strength (Mpa) W/C1 18 25 w/c=5% more Remarks Example: A tipical required value of W/C ratio (as shown in fig.-2) for minimum design strength is determined by the observed data as demontrated below. W/C3 w/c=5% less Mix Design 0.52 21 30 as per design 0.48 27 39 w/c=5% less 0.56 10 15 20 25 30 35 40 45 50 0.560.520.48 CompressiveStrength(MPa) W/C Ratio Fig.- 2 Determination of Actual W/C Ratio Design Strength RequiredW/CRatio Example: For Design Str. = 32 Mpa Requires W/C Ratio = 0.51 20
  21. 21. High Strength Mix METHOD 21
  22. 22. GENERAL FEATURE DESIGN F F F In general, only a natural sand is needed for use of fine aggregate because high strength are rarely obtained with crushed rock fine aggregate. Crushed aggregate (possibly granite) is more preferred than that use of irregular gravel coarse aggregate for strength assurance. Low workability is introduced instead of high degree of workability. This high strength concrete mix design has been developed by B. W. Shacklock and H. C. Erntroy in 1954. For designing concrete mix of low and medium grade compressive strength i.e. up to 35 MPa, it is assumed the strength of fully compacted concrete at a required age to be dependent only on the w/c ratio of the mix. However, compressive strength of high- strength mix above 35 MPa is mainly influenced by the properties of aggregates in addition to that of w/c ratio. The methods of mix design used for medium grade concrete cannot therefore, govern to lead to an accurate estimate of the required mix proportions for high strength concrete under all circumstances. The methods of high strength design-mix has been developed on the basis of these following features: 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 COMPRESSIVESTRENGTH(MPa) REFERENCE NUMBER Fig.1 IRREGULAR GRAVEL COARSE AGGREGATE WITH NATURAL SAND AND ORDINARY PORTLAND CEMENT 22
  23. 23. F F LIMITATION OF HIGH STRENGTH DESIGN F F F Graphical tables are used instead of analytical formulas or so on. F Combined grading of total aggregates may be assumed to be constant with 30% passing in No. #4 sieve (4.75 mm size sieve). No concrete of plastic consistency is suggested to design but only stiff mix is preferred to get high strength. Nominal maximum size of aggregate(NMSA) is taken only up to 20 mm. Maximum. These graphs used (to find out the Reference Number) in this method are obtained from the aggregates containing 30% of material passing through the 4.75 mm sieve. If other grading are used, suitable adjustment have to be made as shown in fig. - 7. An arbitrary reference number is determined from a graph connecting average design strength and reference number which is needed to know the required water cement ratio (w/c) for the particular strength. 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 COMPRESSIVESTRENGTH(MPa) REFERENCE NUMBER Fig. 2 CRUSHED GRANITE COARSE AGGREGATE WITH NATURAL SAND AND ORDINARY PORTLAND CEMENT 23
  24. 24. REQUIRED PARAMETERS OF INGREDIENTS A. CEMENT 1. Grade and type 2. Specific Gravity B. FINE AGGREGATE 1. Gradation (Sieve Analysis) 2. Specific Gravity (SSD Bulk) 3. Absorption C. COARSE AGGREGATE 1. Gradation (Sieve Analysis) 2. Specific Gravity (SSD Bulk) 3. Absorption As usual for designing a concrete mix, it is very much important to be known all information about concrete ingredients i.e. physical test reports. These physical parameters may be obtained by own laboratory - test or by the manufacturer. Basically for the high strength design mix, the following parameters should be available in the time. 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 COMPRESSIVESTRENGTH(MPa) REFERENCE NUMBER Fig. 3 IRREGULAR GRAVEL COARSE AGGREGATE WITH NATURAL SAND AND RAPID HARDENING PORTLAND CEMENT 24
  25. 25. D. WATER 1. Chemical content(free of salt and alkalis) 2. Turbidity (potable or clear) DESIGN PROCEDURE F F F F F Find out the arbitrary reference number according to necessity and availability of concrete materials using fig. 1, 2, 3, 4. Determine the water/cement ratio (w/c) in terms of reference number using fig. 5, 6. Knowing the type of aggregate, size of aggregate, degree of workability and water cement ratio (w/c), find the aggregate/cement ratio using table- 1 or table- 2. Plot the gradation (percentage passing) of available materials i.e. fine aggregate and coarse aggregate as shown in fig. 7 and then determine the required fine aggregate/total aggregate ratio connecting with 30% passing line. Estimate the average design strength using standard deviation or as it is specified for the special job. 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 COMPRESSIVESTRENGTH(MPa) REFERENCE NUMBER Fig. 4 CRUSHED GRANITE COARSE AGGREGATE WITH NATURAL SAND AND RAPID HARDENING PORTLAND CEMENT 25
  26. 26. EQUIPMENT AND APPARATUS For preparing the sample following euipments are needed: 1. 6 nos. Cylinder or Cube Mould 4. Scoop 7. Rubber Mallet 2. Mixer or Mixing Pan 5. Straight Edge 8. Tamping Rod or Vibrator 3. Triple Beam Balance (1 g.) 6.Thermometer 9. Weighing Containers To find out the strength of specimens following equipment are needed : 1. Compressive Strength Machine 2. Triple Beam Balance (1 g.) 3. Rubber Sheet (Filler) To perform a mix design, no special equipment or apparatus is required more than it requires for normal mix design except a special vibrating machine is needed to compact the stiff concrete-sample. For the stiff concrete no hand-mixing is suggested to come true reporting results and hence is always preferred laboratory mixer to mix vigorously. 0.30 0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46 0.48 0.50 0 10 20 30 40 50 60 70 WATER/CEMENTRATIO REFERENCE NUMBER Fig. 5 20 mm. AGGREGATE Degree of Workability 26
  27. 27. 3.0 2.4 3.3 2.9 3.8 2.5 3.2 4.0 2.6 3.6 2.3 4.5 3.0 2.5 3.9 2.6 4.6 3.2 2.6 4.2 2.8 2.3 5.2 3.5 3.0 2.5 4.6 3.1 2.6 5.2 3.6 3.1 2.6 4.7 3.2 2.7 2.3 4.0 3.4 2.9 5.2 3.5 3.0 2.5 4.1 3.5 2.9 5.2 3.6 3.0 2.6 4.4 3.8 3.2 3.9 3.3 2.7 4.5 3.8 3.2 4.0 3.3 2.9 4.9 4.1 3.5 4.3 3.6 3.0 4.9 4.2 3.5 4.4 3.6 3.1 5.3 4.5 3.8 4.7 3.9 3.3 5.3 4.5 3.7 4.8 3.9 3.3 4.8 4.1 5.1 4.2 3.6 4.8 4.0 5.1 4.2 3.6 5.2 4.4 5.4 4.5 3.8 5.1 4.2 5.5 4.5 3.8 5.5 4.7 4.8 4.0 5.4 4.5 4.7 4.0 * Natural sand used in combination with both types of coarse aggregates. + EL = Extremely Low VL = Very Low L = Low M = Medium 0.46 0.48 WaterCementRatio(byweight) 0.34 0.36 0.50 Crushed GraniteIrregular Gravel Degree of Workability + Type & Size of C. A. * EL VL L EL VL L M 20 mm Size 10 mm Size 20 mm Size M EL VL 10 mm Size L ML MEL VL 0.44 0.38 0.40 0.42 0.30 Table- 1: Aggregate / cement ratio (by weight) required to give four degrees of workability with different water cement ratios using Ordinary Portland cement 0.32 0.30 0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46 0.48 0.50 10 20 30 40 50 60 70 WATER/CEMENTRATIO REFERENCE NUMBER Fig. 6 10 mm. AGGREGATE Degree of Workability 27
  28. 28. 2.6 2.9 2.5 3.4 2.2 2.8 3.6 2.4 3.2 4.1 2.7 2.3 3.5 2.4 4.3 2.9 2.4 3.9 2.5 4.8 3.2 2.8 2.3 4.2 2.9 2.4 4.9 3.4 2.9 2.4 4.5 3.0 2.5 5.5 3.7 3.2 2.7 4.9 3.3 2.8 2.3 5.5 3.9 3.3 2.7 5.0 3.4 2.9 2.4 4.2 3.6 3.0 3.7 3.0 2.6 4.2 3.6 3.0 5.5 3.8 3.2 2.7 4.6 4.0 3.4 4.1 3.5 2.9 4.7 4.0 3.3 4.2 3.5 3.0 5.0 4.3 3.7 4.5 3.8 3.2 5.1 4.3 3.6 4.6 3.8 3.2 5.5 4.7 4.0 4.9 4.1 3.5 5.5 4.6 3.9 5.0 4.1 3.4 5.0 4.3 5.2 4.4 3.7 4.9 4.1 5.3 4.4 3.7 * Natural sand used in combination with both types of coarse aggregates. + EL = Extremely Low VL = Very Low L = Low M = Medium 0.36 LEL VL L M M ELEL Type & Size of C. A. * Irregular Gravel Crushed Granite 20 mm Size 10 mm Size 20 mm Size 10 mm Size M Table- 2: Aggregate / cement ratio (by weight) required to give four degrees of workability with different water cement ratios using Rapid Hardening Portland cement Degree of Workability + EL VL L VL LM VL WaterCementRatio(byweight) 0.46 0.48 0.50 0.38 0.40 0.42 0.44 0.32 0.34 Line of 30% Passing RequiredRatio=24% 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 PercentagePassingofC.A. 10 mm 4.75 mm 2.36 mm 1.18 mm 0.60 mm 0.30 mm 0.15 mm PercentagePassingofF.A. 10 mm 20 mm 4.75 mm 2.36 mm 28
  29. 29. Mix Design Data Sheet TRIAL MIX: TM - …. A Project A0 Location A1 Structure A2 Member A3 Concrete Class A4 Type and Brand of Cement A5 Source of Fine Aggregate A6 Type of Coarse Aggregate A7 Source of Coarse Aggregate A8 Specific Gravity of Cement A9 Specific Gravity of Fine Aggregate A10 Specific Gravity of Coarse Aggregate A11 Nominal Max. Size of Coarse Aggregate (mm) A12 Minimum Cylinder Strength Required # (MPa) A13 (# If cube strength is required, select 80% of cylinder strength above) Additional Strength for Safety Factor (MPa) A14 Average Design Cylinder Strength (MPa) A15 Arbitrary Reference Number (from fig. 1, 2, 3 or 4) A16 Degree of Workability (as required) A17 Water Cement Ratio (from fig. 5 or 6) A18 Total Aggregate to Cement Ratio (from table 1 or 2) A19 % of Fine Aggregate to Total Aggregate (from fig. 7) A20 A13+A14 29
  30. 30. Design Steps TRIAL MIX: TM - A A : Mix Proportion by Weight (with reference to cement) 1 Cement B1 2 Water B2 3 Fine Aggregate B3 4 Coarse Aggregate B4 B : Absolute Volume (for 1 m3 ) 1 Cement B5 2 Water B6 3 Fine Aggregate B7 4 Coarse Aggregate B8 B9 Required Weight of - Cement B10 Water B11 Fine Aggregate B12 Coarse Aggregate B13 C : Batching for CEMENT WATER FINE AGGREGATE COARSE AGGREGATE Materials Unit 1 m3 Volume * Lab.Sample for 40 Lit. Vol. A18 A20/(100x A19) {1-(A20/100)}x A19 B1/A9 B4/A11 * Note : Estimated quantity 40 liters is for 6 nos. of cylindrical moulds (size dia. 15 cm & ht. 30 cm.). If it is to prepare 6 nos. of 15x15x15 cm. cubical moulds, take 25 liters volume for laboratory sample. 0.04xB12 0.04xB13 B12 B13Kg Kg 1000/B9 B3xB10 A18 B2xB10 B5+B6+B7+B8 B3/A10 1 B4xB10 Density of Fresh Concrete (Kg/m 3 ) B10+B11+B12+B13 B10 B11 0.04xB10 0.04xB11 Kg Kg 30

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