--- title: "Rate analysis: M20 (1:1½:3) RCC per 10 m³" subject: "Estimating and Costing" chapter: 4 key: "semester_7/estimating_and_costing:rate-m20-rcc-10m3" source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-m20-rcc-10m3 site: BCT Engineering --- # Rate analysis: M20 (1:1½:3) RCC per 10 m³ Estimating and Costing · Chapter 4: Analysis of Rates - Asked in: 2067 Asar (old course), 6 marks - Video: [Rate analysis of concrete. M20 grade of concrete. how to calculate cost of concrete](https://www.youtube.com/watch?v=9R_v5f_XgmA) — civil site knowledge - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-m20-rcc-10m3 - Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-4 ## Question Prepare an analysis of rate for M20 (1:1½:3) for RCC work per 10 m³. ## Short answer For 10 m³ M20 (1:1.5:3) concrete, dry volume 15.4 m³ requires 80.64 bags cement, 4.2 m³ sand, 8.4 m³ aggregate. After labour and plant, with 15% overhead and 10% profit, rate = NPR 294,800 per 10 m³ (29,480/m³). ## Answer Rates and labour norms below are illustrative (DUDBC-style); use the current District Rate for a real estimate. Cement NPR 1,000/bag, sand NPR 3,500/m³, 20 mm aggregate NPR 4,500/m³, skilled NPR 1,500/day, unskilled NPR 1,100/day, overhead 15%, profit 10%. The rate is for concrete only; formwork and reinforcement are paid separately. #### Quantities for 10 m³ of M20 (1:1½:3) - Dry volume $= 1.54 \times 10 = 15.40$ m³; sum of ratio $= 5.5$ - Cement $= 1/5.5 \times 15.40 = 2.800$ m³ $= 80.64$ bags - Sand $= 1.5/5.5 \times 15.40 = 4.200$ m³; aggregate $= 3/5.5 \times 15.40 = 8.400$ m³ - Labour: 12 skilled and 70 unskilled days per 10 m³ (mixing, lifting, placing, vibrating, curing; assumed norm). #### Analysis | Item | Qty | Unit | Rate (NPR) | Amount (NPR) | |---|---:|---|---:|---:| | Cement | 80.64 | bag | 1,000.00 | 80,640.00 | | Sand | 4.200 | m³ | 3,500.00 | 14,700.00 | | Coarse aggregate (20 mm) | 8.400 | m³ | 4,500.00 | 37,800.00 | | Skilled labour (mason) | 12.0 | day | 1,500.00 | 18,000.00 | | Unskilled labour | 70.0 | day | 1,100.00 | 77,000.00 | | Mixer, vibrator and fuel (lump) | 1 | LS | 6,500.00 | 6,500.00 | | Water and curing (lump) | 1 | LS | 1,200.00 | 1,200.00 | | **Direct cost** | | | | **235,840.00** | | Contractor's overhead @ 15% | | | | 35,376.00 | | Contractor's profit @ 10% | | | | 23,584.00 | | **Total (rate per 10 m³)** | | | | **294,800.00** | **Rate of M20 RCC (concrete only) = NPR 294,800.00 per 10 m³** (NPR 29,480.00 per m³). ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. For 10 m3 of M20 concrete, what dry volume of materials is required? A. 10 m3, equal to the wet volume B. 12.7 m3, i.e. 1.27 times the wet volume C. 5.5 m3, the sum of the ratio D. 15.40 m3, i.e. 1.54 times the wet volume Answer: D. Dry materials shrink in volume on mixing, so 1.54 x 10 = 15.40 m3 is needed. (Key point: Dry volume factor) 2. Using the mix 1:1.5:3, how is the cement for 10 m3 obtained? A. 1/5.5 x 15.40 = 2.80 m3, i.e. 80.64 bags B. 1/3 x 15.40 m3 C. 1/4.5 x 10 m3 D. 1/5.5 x 10 m3 Answer: A. The sum of ratio is 1+1.5+3 = 5.5; cement is 1/5.5 of the dry volume, and 2.8 x 28.8 = 80.64 bags. (Key point: Cement quantity) 3. What are the sand and coarse aggregate quantities for 10 m3 of M20? A. Sand 8.40 m3 and aggregate 4.20 m3 B. Sand 4.20 m3 and aggregate 8.40 m3 C. Sand 3.00 m3 and aggregate 6.00 m3 D. Sand 2.80 m3 and aggregate 5.60 m3 Answer: B. Sand = 1.5/5.5 x 15.4 = 4.20 m3; aggregate = 3/5.5 x 15.4 = 8.40 m3. (Key point: Sand and aggregate) 4. What does this M20 RCC rate cover? A. Concrete, formwork and reinforcement together B. Concrete and reinforcement only C. Concrete only; formwork and reinforcement are paid separately D. Concrete excluding labour and equipment Answer: C. The answer states the rate is for concrete only, with formwork and steel paid separately. 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