Recommended Concrete Mixes for Various Types of Construction Works:Various types of concrete construction requires different concrete mixes for its construction. The recommended value of these concrete mixes for various types of construction is presented in table below:
Table: Recommended mixes for Different Concrete Construction
|Type of work||Concrete Mix Ratio||Max. size of aggregates (mm)||Water for dry aggregates (liter)*||Water for aggregates condition from dry to moist batch (liter)*||Water for best consistency (liter)*|
|Small precast work, fence posts, poles, garden furniture and other work of very thin sections||1:2:2||16||20||15 to 16||Soft|
|Storage tanks, cisterns, sewers, well knerbs, watertight work, and columns or other structural parts subjected to high stresses||1:2:3||20||25||19 to 22||Medium|
|Reinforced concrete work, floor slab, beams, columns, arches, stairs etc||1:2.5:3.5||20||32||23 to 27||Medium or soft|
|Ordinary floors, footpaths, drive ways, steps, roads, pavements||1:2.5:3.5||20||23||20 to 23||Stiff|
|Building and basement walls, silos, sills, lintels, machine foundations subject to vibration, bridges, dams, piers, etc exposed to action of water and frost foundation concrete for masonry walls||1:2:4||40||30||23 to 26||Stiff or Medium|
|Culverts, retaining walls, compound walls, ordinary machine bases, etc.||1:3:5||40||34||26 to 30||Stiff or Medium|
|Mass concrete for heavy walls, lean concrete for levelling course of RCC foundations||1:3:6||63||36||30 to 32||Medium|
NOTES: When both fine and coarse aggregates are poorly graded, the following general rules regarding suitable proportioning of these will be found helpful:
- For maximum size of coarse aggregates as 40mm and over, sand should be half as much as coarse aggregates.
- For maximum size of coarse aggregates as 20mm and over, sand should be two-thirds as much as coarse aggregates.
- For maximum size of coarse aggregates as 16mm, sand and coarse aggregates should be in equal parts.