"Cement the slab" and "concrete the wall" are heard on every site, and they mix up three different materials. Getting them straight helps when reading drawings and ordering.
Three Materials
| Cement | Mortar | Concrete | |
|---|---|---|---|
| What it is | Binder powder | Cement + sand + water | Cement + sand + aggregate + water |
| Coarse aggregate | No | No | Yes |
| Typical ratios | — | 1:3 to 1:6 | 1:1.5:3 (M20), 1:2:4 (M15) |
| Main uses | Ingredient | Masonry, plaster, pointing | Foundations, frame, slabs, floors |
| Strength role | Binds | Joins and finishes | Carries load |
Concrete with steel bars is RCC; without steel it is PCC.
Why Not Use Cement Alone?
Neat cement paste shrinks a great deal as it hardens and cracks badly, generates a lot of heat, and would be very expensive in bulk. Sand and aggregate form a skeleton that the cement paste glues together — cheaper, stronger in bulk and far more stable.
How Much Cement Is in Each?
| Material | Cement per m³ (typical) |
|---|---|
| M20 concrete (1:1.5:3) | about 8 bags |
| M15 concrete (1:2:4) | about 6.3 bags |
| 1:4 mortar | about 7.3 bags |
| 1:6 mortar | about 5.2 bags |
The Short Version
Cement binds, mortar joins and finishes, concrete carries load, and RCC is concrete with steel. Order cement in bags; specify mortar by ratio and concrete by grade.
