Concrete measurement practices: which of the following statements about weighing and measuring ingredients, and finished concrete volume, are correct?
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AThe weight of ingredients of concrete mix is taken in kilograms
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BWater and aggregates are measured in litres
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CThe finished concrete is measured in cubic metres
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D20 bags of cement make one tonne
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EAll the above
Answer
Correct Answer: All the above
Explanation
Introduction / Context:Concrete batching involves measuring each ingredient precisely. Standardized measurement practices ensure consistency, quality, and comparability across sites and batches.
Given Data / Assumptions:
- Ingredients include cement, water, fine and coarse aggregates.
- Commonly used cement bag weight is 50 kg in India.
- Output of concrete is measured in volume (cubic metres).
Concept / Approach:Cement and aggregates are generally weighed in kilograms, while water can be measured in litres. Finished concrete is always accounted for in cubic metres for billing and structural design. 20 bags of cement (20 × 50 kg) = 1000 kg = 1 tonne, confirming the statement.
Step-by-Step Solution:Cement: measured by weight in kg.Water/aggregates: litres (volume) for water, weight/volume for aggregates.Concrete output: cubic metres.20 bags × 50 kg = 1000 kg = 1 tonne.
Verification / Alternative check:Specifications in IS 456 and IS 10262 clearly refer to batching by weight, and payment for concrete is always in cubic metres.
Why Other Options Are Wrong:
- No single statement is wrong; each reflects industry practice.
Common Pitfalls:
- Assuming aggregates are always measured in litres; weight batching is more accurate but volume batching is used in small sites.
Final Answer:All the above