The Right Materials for Concrete
- Ensure aggregates are hard, strong and free from dust, dirt, clay, silt and vegetable matter.
- Remove organic matter like tree leaves, dry tobacco, grass, roots and sugar substances.
- Use rough/coarser aggregate for concreting.
- Coarse aggregate shall be roughly cubical with a combination of 10 millimetres and 20 millimetres in the ratio of 60:40 to 70:30.
- Do not use elongated (long) and flaky (thin) aggregates – the limit for such aggregates is 30% by mass in combination and individually 15% by mass.
- Select sand, which when squeezed by hand, does not leave stains and fine particles sticking to the palm. Stains indicate presence of clay and fine, sticky particles indicate presence of silt.
- Stains indicate presence of clay and sticking fine particles indicates presence of silt.
- Water should be free from oil, alkalis, acids, sugar and salts.
- Water fit for drinking is most suitable for making concrete.
- Seawater or brackish (salty) water should not be used for making RCC.
- Do not add more than 26 litres of water with each bag of cement.