Experts Construction Tips
Proportions
Using the right proportions of raw material is essential for obtaining an optimum quality of concrete mix. Although it is advisable to seek professional advice for determining the proportions, this chart can be used as a ready reference:
| Use/Application | Proportion on volumetric basis | ||
|---|---|---|---|
| Cement | Sand | Stone Aggregates | |
| Plain Cement Concrete (PCC) | 1 | 3 | 6 |
| RCC footing column, beam, slab, etc. | 1 | 1.5 | 3 |
| Brick Masonry (23 cm and above) | 1 | 6 | - |
| Brick Masonry (Less than 23 cm) | 1 | 3 | - |
| Cement plaster on wall | 1 | 4 | - |
| Cement plaster on ceiling | 1 | 3 | - |
| Ceramic tiles fixing | 1 | 4 | - |
| IPS flooring | 1 | 2 | 4 |
| Cement concrete for footpath/internal roads in housing societies | 1 | 1.5 | 3 |
Note: It is preferable to use fine sand for plastering work and coarse sand for masonry, PCC, RCC & CC Road work.
Deshuttering Period
Deshuttering period relates to the maturity of concrete and depends on the ambient temperature. Forms shall not struck until the concrete has reached strength at least twice the stress of which the concrete may be subjected at the time of removal of form work.
Assuming standard conditions of workmanship and quality of materials, you can refer to the following time-frames for the removal of forms.
| Form | Summers | Winters (Temp <18° C) |
|---|---|---|
| Walls, columns and vertical faces of structural members | 24 hrs. | 48 hrs. |
| Removal of props under slab Spanning up to 4.5 m | 7 days | 14 days |
| Removal of props under beams and arches spanning up to 6 m | 14 days | 28 days |
