How are the bricks for 150 m3 found?

Bricks per m3 (1 / volume of brick with mortar = 534.19) x 150

150 divided by the brick-only volume

Wall area divided by brick face area only

What gives the dry mortar for the 150 m3 of 1:4 brickwork?

Wet mortar 0.2567 m3 per m3 x 150 = 38.50 m3, times 1.27 = 48.90 m3 dry

1.27 x 150 with no deduction for bricks

How are cement and sand for 120 m2 of 20 mm plaster (1:4) obtained?

Wet mortar = 120 x 0.02 = 2.4 m3; dry = 1.27 x 2.4 = 3.048 m3; cement 1/5, sand 4/5

Wet mortar = 120 x 0.20 m3; cement 1/4

Dry = 1.54 x 2.4; cement 1/4 and sand 3/4

Wet mortar = 120 x 0.02; cement 1/4 and sand 4/4 of wet volume

2067 Poush (old course)

Materials: 150 m³ brick 1:4, 120 m² plaster

Short answer

For 150 m3 brickwork in 1:4 mortar, assuming 230x110x55 mm bricks with 10 mm joints and dry volume 1.27 times wet: bricks 80,129, cement 281.6 bags, sand 39.12 m3. For 120 m2 20 mm plaster: cement 17.6 bags, sand 2.44 m3. Totals: cement 299.2 bags, sand 41.56 m3.

Calculate the quantities of materials required for the following works: i) 150 m³ of brick work in (1:4) cement mortar in super structure ii) 120 m² of 20 mm thick cement sand plaster (1:4).

Assumptions: dry volume 1.27 × wet for mortar; 1 m³ cement = 28.8 bags; brick 230 × 110 × 55 mm with 10 mm joints (not given); no wastage.

(i) 150 m³ of brickwork in 1:4 mortar

Brick with mortar $= 0.240 \times 0.120 \times 0.065 = 1872.0\times 10^{-6}$ m³; bricks per m³ $= 1/(1872.0\times10^{-6}) = 534.19$
Bricks for 150.00 m³ $= 534.19 \times 150.00 = 80,128$ nos (say 80,129)
Volume of bricks only $= 0.230\times0.110\times0.055 = 1391.5\times10^{-6}$ m³ each; wet mortar per m³ $= 1 - 534.19\times1391.5\times10^{-6} = 0.2567$ m³
Wet mortar for 150.00 m³ $= 38.502$ m³; dry $= 1.27\times38.502 = 48.897$ m³
Cement $= 1/5\times48.897 = 9.779$ m³ $= 281.6$ bags
Sand $= 4/5\times48.897 = 39.118$ m³

(ii) 120 m² of 20 mm plaster (1:4)

Wet mortar $= 120.0 \times 0.0200 = 2.4000$ m³; dry volume $= 1.27 \times 2.4000 = 3.0480$ m³
Cement $= 1/5 \times 3.0480 = 0.6096$ m³ $= 17.56$ bags
Sand $= 4/5 \times 3.0480 = 2.4384$ m³

Answer: (i) bricks 80,129, cement 281.6 bags, sand 39.12 m³. (ii) cement 17.6 bags, sand 2.44 m³. Total cement = 299.2 bags; total sand = 41.56 m³.

✓ Answer checked by Claude Opus 5.5 (high effort)

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Materials: 150 m³ brick 1:4, 120 m² plaster

(i) 150 m³ of brickwork in 1:4 mortar

(ii) 120 m² of 20 mm plaster (1:4)

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