DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method

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In this article, We’re going to create the DOE Method of Concrete Mix Design (Concrete Mix Design by DOE Method) with a concrete mix design example for a better explanation for making this concrete mix design calculation easy to understand so read the whole article download concrete mix design doe method pdf.

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DOE Method of Concrete Mix Design

The DOE method was first introduced (published) in 1975 and then revised in 1988.

DOE Method of Concrete Mix Design Concrete Mix Design by DOE Method_result
DOE Method of Concrete Mix Design Concrete Mix Design by DOE Method

While Grading Curve Method was specifically developed for concrete pavements, the DOE method applies to concrete for most purposes, including roads.

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Since the DOE method presently is the standard British method of concrete mix design, the procedure involved in this method is described instead of the outdated Road Note No 4 method.

Step 1: Required Data for DOE Method of Concrete Mix Design

  • Fineness modulus of selected F.A.
  • Unit weight of dry rodded coarse aggregate.
  • Sp. gravity of coarse and fine aggregates in SSD condition
  • Absorption characteristics of both coarse and fine aggregates.
  • The specific gravity of cement.

Let me take a concrete mix design example for data to make it easy to understand

  1. Grade Designation = M 30
    • For which we have to design concrete mix to achieve this particular strength of concrete for construction work of the project
  2. Type of cement = O.P.C- 43 grade
    • More than 17 different types of cement available for special construction work and every condition demand different material to more suitable, economical and durable structure.
  3. Fine Aggregate = Zone-II
  4. Sp. Gravity Cement = 3.15
  5. Fine Aggregate = 2.61
  6. Coarse Aggregate (20mm) = 2.65
  7. Coarse Aggregate (10mm) = 2.66

Step 2: Find Target Mean Strength

Find the target mean strength from the specified characteristic strength (Grade Designation) 

Target mean strength = specified characteristic strength + (Standard deviation x risk factor)

Where risk factor is on the assumption that 5 percent of results are allowed to fall less than the specified characteristic strength.

𝑓𝑚=30+(1.65 𝑥 5.0)

𝑓𝑚=38.25 𝑀𝑃𝑎

Step 3: Calculate Water/cement ratio

Calculate the water/cement ratio. This is done in a rather round about method, using Table 11.11

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WC ratio as per british method

Referring to Table 11.11, for OPC, uncrushed aggregate, for W/C ratio of 0.5, 28 days compressive strength is 49 MPa.

DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method

In the above Fig. find an intersection point for 42 MPa and 0.5 W/C ratios. Draw a dotted line curve parallel to the neighbouring curve. From this curve read off the W/C ratio for a target mean strength of 39 MPa.

The Water/cement ratio is = 0.58 

Check this W/C ratio from durability consideration from Table 9.20. The maximum W/C ratio permitted is 0.50. Adopt lower of the two Therefore adopt a W/C ratio of 0.50

Concrete Mix Design by DOE Method

Step 4: Calculation of Water Content

  • Next, Decide the water content for the slump of 75 mm (assumed) 20 mm uncrushed aggregate from Table 11.12.
  • In the case of CA & FA are different
  • Water demand for natural fine aggregate = 195 lit
  • Water demand for crushed coarse 20mm max size aggregate = 225 lit

𝑊𝑎𝑡𝑒𝑟 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 = [(2/3)×W𝑓]+[(1/3)×W𝑐𝑎]

𝑊𝑎𝑡𝑒𝑟 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 = [2/3×195]+[1/3×225]

𝑊𝑎𝑡𝑒𝑟 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 = 205.0 𝑘𝑔𝑚3

Table 11.12: Approximate Free Water Contents Required to Give Various Levels of Workability According to the 1988 British method

DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method

Step 5: Calculating Cement Content

Mixing water content is 205 kg/m3 of concrete.

𝐶𝑒𝑚𝑒𝑛𝑡 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 = 205/0.50

𝐶𝑒𝑚𝑒𝑛𝑡 𝐶𝑜𝑛𝑡𝑒𝑛𝑡=410.0 𝑘𝑔𝑚3

Which is more than 350 kg (As per Table No. 9.2 of BS 8110: Part I: 1985) Hence o.k.

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Step 6: Calculating Weight of Total Aggregate

  • This requires an estimate of the wet density of the fully compacted concrete. This can be found out in Fig. 11.4 for approximate water content and specific gravity of aggregate.
  • Next, find out the density of fresh concrete from Fig. 11.4 for the water content of 205 kg/m3, 20 mm uncrushed aggregate of sp.gr. 2.65

The wet density = 2375.0 kgm3

Concrete Mix Design by DOE Method | Calculating Weight of Total Aggregate

The total weight of aggregate is found out for DOE Method of Concrete Mix Design

Weight of Total Aggregate = The wet density – (Weight of Cement + Weight of Free Water)

Weight of Total Aggregate = 2375 – (410 + 205)

Weight of Total Aggregate = 1760 kg/m3

Step 7: Calculating Weight of Fine Aggregate

Then, the proportion of fine aggregate is determined in the total aggregate using below Fig. Fig. (a) is for 10 mm size, (b) is for 20 mm size and Fig. (c) is for 40 mm size coarse aggregate.

Calculating Weight of Fine Aggregate | Concrete Mix Design by DOE Method
Also ReadConcrete Mix Design by IS, ACI and BS Methods: A Comparative Analysis

The parameters involved are the maximum size of coarse aggregate, the level of workability, the water/cement ratio, and the percentage of fine spassing 600 μ seive.

DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method

For 20 mm aggregate size, W/C ratio of 0.50, Slump of 75 mm, for 50% fines passing through 600 μ sieve, the percentage of

DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method

% 𝐹𝑖𝑛𝑒 𝐴𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 = 41 %

Weight of F.A. = 1760 × (41/100)

Weight of F.A. = 721.6 kg/m3

and

Weight of C.A. = 1760 × (59/100)

Weight of C.A. = 1038.4 kg/m3

Step 8: Combination of Different Coarse Aggregate Fractions

Coarse aggregate can be further divided into different fractions depending on the shape of aggregate. As general guidance, the figures given in Table 11.14 can be used.

DOE Method of Concrete Mix Design | Concrete Mix Design by DOE Method
Also Read: How to Design Two Way Slab EXCEL Sheet by civil experience

Step 9: Proportions for DOE Method of Concrete Mix Design

Ingredients

Quantity kg/m3

Ratio

1 Bag Cement

Cement

410

1

50

Fine Aggregate

721.6

1.76

88

Coarse Aggregate

1038.4

2.54

127.0

Water

205

0.50

25

Chemical

NM

NM

NM

Step 10: Adjustment for Field Condition

The proportions are required to be adjusted for the field conditions. Fine Aggregate has surface moisture of 2 %

Weight of F.A. = 721.6 + (2/100) 721.6

Weight of F.A. = 736.03 kg/m3

Coarse Aggregate absorbs 1% of water

Weight of C.A. = 1038.4 – (1/100) 1038.4

Weight of C.A. = 1028 kg/m3

Step 11: Final Design Proportions

Ingredients

Quantity kg/m3

Ratio

1 Bag Cement

Cement

410

1

50

Fine Aggregate

728

1.80

90.0

Coarse Aggregate

1029.1

2.51

125.5

Water

205

0.50

25.0

Chemical

NM

NM

NM

Also ReadConcrete Mix Design as per IS CODE easy way by excel sheet

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FAQ 1:  Which Data Required for DOE Method of Concrete Mix Design?

1. Fineness modulus of selected F.A.2. Unit weight of dry rodded coarse aggregate.3. Sp. gravity of coarse and fine aggregates in SSD condition4. Absorption characteristics of both coarse and fine aggregates.5. Specific gravity of cement.

FAQ 2:  How to Find Target Mean Strength for DOE Method of Concrete Mix Design?

Find the target mean strength from the specified characteristic strength (Grade Designation) Target mean strength = specified characteristic strength + (Standard deviation x risk factor)Where risk factor is on the assumption that 5 percent of results are allowed to fall less than the specified characteristic strength.

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