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Materials: 75 m³ brick 1:3, 115 m² PCC floor

Short answer

For 75 m³ brickwork in 1:3 mortar: bricks 40,065 nos, cement 176.0 bags, sand 18.34 m³. For 115 m² 75 mm thick PCC floor in 1:2:4: wet volume 8.625 m³, dry 13.283 m³; cement 54.6 bags, sand 3.80 m³, aggregate 7.59 m³.

Calculate the quantities of materials required for the following items of work: (i) 75 m³ of brick work in (1:3) cement mortar (ii) 115 m² of 75 mm thick PCC (1:2:4) in floor.

Assumptions: dry volume = 1.54 × wet volume for concrete and 1.27 × wet volume for mortar; 1 m³ of cement = 28.8 bags of 50 kg; no wastage is added. Brick size is not given, so a standard brick of 230 × 110 × 55 mm with 10 mm joints is assumed.

(i) 75 m³ brickwork in 1:3 mortar

  • Brick with mortar =0.240×0.120×0.065=1872.0×10−6= 0.240 \times 0.120 \times 0.065 = 1872.0\times 10^{-6} m³; bricks per m³ =1/1872.0×106=534.19= 1/1872.0\times10^6 = 534.19
  • Bricks for 75.00 m³ =534.19×75.00=40,064= 534.19 \times 75.00 = 40,064 nos (say 40,065)
  • Volume of bricks only =0.230×0.110×0.055=1391.5×10−6= 0.230\times0.110\times0.055 = 1391.5\times10^{-6} m³ each; wet mortar per m³ =1−534.19×1391.5×10−6=0.2567= 1 - 534.19\times1391.5\times10^{-6} = 0.2567 m³
  • Wet mortar for 75.00 m³ =19.251= 19.251 m³; dry =1.27×19.251=24.449= 1.27\times19.251 = 24.449 m³
  • Cement =1/4×24.449=6.112= 1/4\times24.449 = 6.112 m³ =176.0= 176.0 bags
  • Sand =3/4×24.449=18.336= 3/4\times24.449 = 18.336 m³

(ii) 115 m² × 75 mm PCC (1:2:4)

  • Wet volume =8.625= 8.625 m³; dry volume =1.54×8.625=13.283= 1.54 \times 8.625 = 13.283 m³ (sum of ratio =7= 7)
  • Cement =1/7×13.283=1.898= 1/7 \times 13.283 = 1.898 m³ =1.898×28.8=54.6= 1.898 \times 28.8 = 54.6 bags (50 kg)
  • Sand =2/7×13.283=3.795= 2/7 \times 13.283 = 3.795 m³
  • Coarse aggregate =4/7×13.283=7.590= 4/7 \times 13.283 = 7.590 m³

Answer: (i) bricks 40,065; cement 176.0 bags; sand 18.34 m³. (ii) cement 54.6 bags; sand 3.80 m³; aggregate 7.59 m³.

✓ Answer checked by Claude Opus 5.5 (high effort)

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