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Concrete · DOE / BRE method

Concrete Mix Design (DOE)

Design of Normal Concrete Mixes, stage by stage — target mean strength, free-water/cement ratio, cement and water contents, then the fine and coarse aggregate split. Every value shows the table, figure or calculation it came from, and the mix converts to site batching quantities.

1 · Strength specification

Items 1.1–1.8 of the DOE form

Characteristic strengthN/mm²Strength at ageProportion defectiveStandard deviationCement strength classCoarse aggregateFine aggregateMaximum free-water/cement ratiooptionalFrom the exposure class — the lower of this and the strength value governs.

2 · Workability

Items 2.1–2.3

SlumpMaximum aggregate size

3 · Cement content limits

Items 3.2 and 3.3 — optional

Minimum cement contentkg/m³Maximum cement contentkg/m³

4 · Aggregates

Items 4.1 and 5.1

Relative density (SSD)Figure 5 covers 2.4 to 2.9.Passing 600 µm sieve%Grading of the fine aggregate, from the sieve analysis.

5 · Site quantities

Moisture and absorption of the aggregates as delivered

Fine — moisture%Fine — absorption%Coarse — moisture%Coarse — absorption%Trial mix volumem³

Target mean strength

43.1 N/mm²

30.0 + 13.1 margin

Free-water/cement ratio

0.481

governing value

Free-water content

180 kg/m³

Table 3

Cement content

374 kg/m³

Concrete density

2370 kg/m³

Figure 5

Total aggregate

1816 kg/m³

Fine aggregate

593 kg/m³

32.6 % of the total

Coarse aggregate

1224 kg/m³

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