---
title: "DOE method of mix design steps"
subject: "Concrete Technology and Masonry Structure"
chapter: 3
key: "semester_5/concrete_technology_and_masonry_structure:doe-mix-design-steps"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/doe-mix-design-steps
site: BCT Engineering
---

# DOE method of mix design steps

Concrete Technology and Masonry Structure · Chapter 3: Mix design of concrete and property of green concrete

- Asked in: 2082 Bhadra, 6 marks; 2081 Baisakh, 4 marks; 2079 Bhadra, 8 marks; 2078 Bhadra, 8 marks; 2075 Chaitra, 2+6 marks; 2074 Chaitra, 7 marks; 2071 Chaitra, 8 marks; 2069 Chaitra, 6 marks (asked 8 times)
- Video: [British DoE (Department of Environment) Method of Mix Design](https://www.youtube.com/watch?v=NnAAEeIJgkc) — Ceylara Academy
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/doe-mix-design-steps
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-3

## Question

Describe the stepwise procedure of concrete mix design by the DOE method (key concepts, with schematic diagram and table where possible).

## Short answer

DOE method: target mean strength f_m = f_ck + 1.64s; w/c from chart; free water from table (slump, size, aggregate type); wet density from chart; total aggregate = density - cement - water; fine aggregate % from chart (600 µm passing). Example: target 38.2 MPa gives w/c 0.48, water 205 kg/m³, cement 427 kg/m³, total aggregate 1768 kg/m³.

## Answer

The **DoE (British) method** (UK Department of the Environment; BRE 1988 "Design of normal concrete mixes", which replaced the older Road Note No. 4 method) selects the mix from charts and tables. It is based on the w/c ratio, the free-water content and the proportion of fine aggregate.

#### Key concepts
- Target mean strength = characteristic strength + margin, where margin = $k \times s$.
- The w/c ratio is read from the strength vs w/c chart for the type of cement and aggregate, and compared with the durability limit.
- The free-water content depends on the slump/Vebe time, the maximum size and the aggregate type (crushed/uncrushed).
- The wet density of fresh concrete comes from a chart (it depends on the free water and the aggregate density).
- The fine aggregate proportion comes from a chart (maximum size, slump, w/c, grading zone).

```text
 f_ck -> target f_m -> w/c (chart) -+
 slump,size,type -> water (table) --+-> cement
 free water + SG -> density (chart) -> total aggregate
 w/c,slump,zone -> %fines (chart)  -> FA, CA
```

#### Steps
1. **Target mean strength**: $f_m = f_{ck} + 1.64 s$ (margin $= k s$, $k = 1.64$ for 5% defectives; IS uses $1.65 s$). The standard deviation $s$ comes from site data or a table (e.g. 4-5 MPa).
2. **w/c ratio**: Table 2 gives the 28-day strength at w/c 0.5 for the cement/aggregate type; draw the curve through this point on Fig 1 and read the w/c for the target strength. Check the maximum w/c limit for the exposure.
3. **Free-water content** from Table 3 (kg/m$^3$) for the slump (0-10, 10-30, 30-60, 60-180 mm), the size (10, 20, 40 mm) and crushed/uncrushed aggregate.
4. **Cement content** = water/(w/c); check the minimum and maximum limits (e.g. 300 and 550 kg/m$^3$).
5. **Wet density** of concrete from Fig 3 (free water, aggregate SG).
6. **Total aggregate content** = wet density - cement - water.
7. **Proportion of fine aggregate** from Fig 4 (using the % passing the 600 micron sieve).
8. **Fine and coarse aggregate** = proportion $\times$ total aggregate; the coarse aggregate is split into sizes (e.g. 10/20/40 mm in the ratio 1:1.5:3).
9. **Trial mix**: check the workability and strength, and adjust.

#### Sample table (illustration)
| Item | Value |
|---|---|
| f_ck / target | 30 / 38.2 MPa |
| w/c | 0.48 |
| Water | 205 kg/m$^3$ |
| Cement | 427 kg/m$^3$ |
| Wet density | 2400 kg/m$^3$ |
| Total aggregate | 1768 kg/m$^3$ |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. In DoE, target mean strength is...
   A. fck - ks
   B. fck + ks, k = 1.64 for 5% defectives
   C. fck
   D. fck + 10
   Answer: B. Margin = k s added to characteristic strength. (Key point: Target mean)

2. Total aggregate content equals...
   A. Wet density - cement - water
   B. Cement + water
   C. Water / w/c
   D. Density x 0.5
   Answer: A. Wet density of fresh concrete less cement and free water. (Key point: Total aggregate)

3. Proportion of fine aggregate is read from a chart using...
   A. Max size, slump, w/c and grading zone (% passing 600 micron)
   B. Cement type only
   C. Density only
   D. Curing
   Answer: A. Fig 4 gives % fines. (Key point: Fine proportion)

4. Free-water content depends on...
   A. Slump/Vebe, max size and crushed/uncrushed type
   B. Strength only
   C. Cement colour
   D. Age
   Answer: A. Taken from table for those factors. (Key point: Free water)

## Related in Concrete Technology and Masonry Structure

- [DOE mix design for M25 concrete (numerical)](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Adoe-mix-design-m25-numerical) — Concrete Technology and Masonry Structure, chapter 3
- [Fundamental concepts of concrete mix design](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Amix-design-fundamental-concepts) — Concrete Technology and Masonry Structure, chapter 3
- [IS method of mix design steps](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ais-method-mix-design-steps) — Concrete Technology and Masonry Structure, chapter 3, asked 3×
- [ACI method of mix design steps](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aaci-mix-design-steps) — Concrete Technology and Masonry Structure, chapter 3, asked 9×
- [Principles of mix design; factors not in DOE](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Amix-design-principles-doe-omitted) — Concrete Technology and Masonry Structure, chapter 3
- [DoE mix design for fck 35 MPa (numerical)](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Adoe-mix-design-fck35-numerical) — Concrete Technology and Masonry Structure, chapter 3

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