According to standard productivity norms, what is the expected daily out-turn of cement concrete 1:2:4 (nominal mix) placed by one mason under ordinary site conditions?
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A1.5 m^3
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B2.5 m^3
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C3.5 m^3
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D5.0 m^3
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E1.0 m^3
Answer
Correct Answer: 2.5 m^3
Explanation
Introduction / Context:Out-turn norms guide planning and scheduling for concrete works. They depend on mixing method, transport distance, placing constraints, and finishing. For nominal mixes such as 1:2:4, exam-standard planning values are used to avoid over- or under-allocation of labour.
Given Data / Assumptions:
- Cement concrete nominal mix 1:2:4.
- One mason assisted by helpers under normal conditions.
- Non-mechanized or basic mechanized handling with typical haul distances.
Concept / Approach:Published handbooks and SOR references typically place daily mason output for 1:2:4 concrete around 2.0–3.0 m^3, with 2.5 m^3 as a widely accepted central value for planning. Higher figures assume better mechanization and ideal logistics; lower figures reflect constraints or complex formwork.
Step-by-Step Solution:Identify the typical range for manual/semimanual concrete placement.Select a median planning benchmark: 2.5 m^3 per mason per day.Confirm that this value aligns with many question banks and schedule norms.
Verification / Alternative check:Cross-checking references shows 2–3 m^3 as common; 2.5 m^3 is therefore a reasonable expected out-turn for exam purposes.
Why Other Options Are Wrong:
- 1.5 m^3 or 1.0 m^3: Too conservative for normal conditions.
- 3.5 m^3 or 5.0 m^3: Optimistic unless highly mechanized or exceptionally favourable conditions exist.
Common Pitfalls:Ignoring delays due to formwork or reinforcement congestion; not considering transport distances or vibration/finishing time.
Final Answer:2.5 m^3