Skip to main content

Materials for 12 cm RCC slab

Short answer

Slab volume is 1.512 m³; dry volume 2.328 m³ for 1:1.5:3 mix. Cement = 12.2 bags (0.423 m³), sand = 0.635 m³, coarse aggregate = 1.270 m³.

Estimate the quantities of cement, sand and coarse aggregate required for 12 cm thick RCC slab of (1:1½:3) mix proportion. The outside dimensions of slab are 4.20 m × 3 m.

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. The slab is taken as one rectangle of the outside dimensions given and the volume of steel is not deducted.

  • Volume of slab =4.20×3.00×0.12=1.512= 4.20 \times 3.00 \times 0.12 = 1.512 m³

Concrete 1:1½:3

  • Wet volume =1.512= 1.512 m³; dry volume =1.54×1.512=2.328= 1.54 \times 1.512 = 2.328 m³ (sum of ratio =5.5= 5.5)
  • Cement =1/5.5×2.328=0.423= 1/5.5 \times 2.328 = 0.423 m³ =0.423×28.8=12.2= 0.423 \times 28.8 = 12.2 bags (50 kg)
  • Sand =1.5/5.5×2.328=0.635= 1.5/5.5 \times 2.328 = 0.635 m³
  • Coarse aggregate =3/5.5×2.328=1.270= 3/5.5 \times 2.328 = 1.270 m³

Answer: cement = 12.2 bags (0.423 m³); sand = 0.635 m³; coarse aggregate = 1.270 m³.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Estimating and Costing chapter 4 questions →