The Department of Environment (DOE) method is basically used for which of the following purposes? (i) Concrete mix design (ii) Road mix design (iii) Mix Design with pulverized fuel ash (iv) Mix Design with GGBFS
- A(i), (ii), (iii), and (iv)
- BBoth (iii) and (iv)
- CBoth (i) and (ii)
- DOnly (i), (iii), (iv)Correct
Solution
Concept
The DOE method is a British method for concrete mix design. It also has extra steps for mixes with PFA (fly ash) and GGBFS.
Step-by-step solution
1. The DOE method was developed in the UK (1975, revised 1988). 2. It is used to design normal concrete mixes, so (i) is correct. 3. The revised method has extra steps for mixes with pulverized fuel ash (PFA), so (iii) is correct. 4. It also has extra steps for mixes with ground granulated blast furnace slag (GGBFS), so (iv) is correct. 5. It is not used for road (bituminous) mix design, so (ii) is wrong. 6. Correct statements are (i), (iii) and (iv). Answer is D.
Explanation
The DOE method is a British method for concrete mix design. It also covers mixes with fly ash (PFA) and slag (GGBFS). It is not used for road mixes. Bituminous road mixes use the Marshall method.
Why the other options are wrong
A: includes road mix design, which is wrong. B: misses normal concrete mix design, which is the main use. C: includes road mix design and misses PFA and GGBFS.
Shortcut
DOE = British concrete mix design method (with PFA and GGBS options). Road mix = Marshall method.
Common mistake
Thinking DOE is a road or highway method because of the word 'Department'.
Correct answer: D) Only (i), (iii), (iv)