| | Relation between water/cement ratio and average compressive strength of concrete (Fm) |
|---|
| average compressive strength at 28 days (kg/cm2) | effective water/cement ratio(by mass) {Non-Airentrained Concrete} | effective water/cement ratio(by mass){Airentrained Concrete} | | 350 | 0.48 | 0.4 | | 300 | 0.55 | 0.46 | | 250 | 0.62 | 0.53 | | 200 | 0.7 | 0.61 | | 150 | 0.8 | 0.71 |
| Relation between water/cement ratio and average specified compressive strength of concrete (Fcu) |
|---|
| average compressive strength at 28 days (kg/cm2) | effective water/cement ratio(by mass) {Non-Airentrained Concrete} | effective water/cement ratio(by mass){Airentrained Concrete} | | 250 | 0.5 | 0.39 | | 200 | 0.6 | 0.49 | | 170 | 0.66 | 0.54 |
| Requirement for water / cement ratio and strength for special conditions |
|---|
| Exposure Condition | Maximum w/c ratio | Minimum design strength (kg/cm2) | | Fresh Water | 0.5 | 250 | | Brackish or sea water | 0.45 | 300 | | Kerbs, gutters or gardrails | 0.45 | 300 | | In the presence of deicing chemicals | 0.45 | 300 | | De-icing salts, brackish water, sea water | 0.4 | 330 |
| Approximate requirement for mixing water and air content for different workabilities and nominal maximum sizes of aggregate (Non-air entrained) |
|---|
| Workability or Air content | 10 | 12.5 | 20 | 25 | 40 | 50 | 70 | | 30 - 50 | 205 | 200 | 185 | 180 | 160 | 155 | 145 | | 80 - 100 | 225 | 215 | 200 | 195 | 175 | 170 | 160 | | Approximate entrapped air content(%) | 3 | 2.5 | 2 | 1.5 | 1 | 0.5 | 0.3 |
| Approximate requirement for mixing water and air content for different workabilities and nominal maximum sizes of aggregate (Air entrained) |
|---|
| Workability or Air content | 10 | 12.5 | 20 | 25 | 40 | 50 | 70 | | 30 - 50 | 180 | 175 | 165 | 160 | 145 | 140 | 135 | | 80 - 100 | 200 | 190 | 180 | 175 | 160 | 155 | 150 | | Average total air content(%) | 6 | 5.5 | 5 | 4.5 | 4.5 | 4 | 3.5 |
| Dry bulk volume of coarse aggregate per unit volume of concrete |
|---|
| Maximum size of aggregate | 2.4 | 2.6 | 2.8 | 3.0 | | 10 | 0.5 | 0.48 | 0.46 | 44 | | 12.5 | 0.59 | 0.57 | 0.55 | 53 | | 20 | 0.66 | 0.64 | 0.62 | 60 | | 25 | 0.71 | 0.69 | 0.67 | 65 | | 40 | 0.75 | 0.73 | 0.71 | 69 | | 50 | 0.78 | 0.76 | 0.74 | 72 | | 70 | 0.82 | 0.8 | 0.78 | 76 |
| First estimate of density (unit weight) of concrete |
|---|
| Maximum size of aggregate | First estimate of density of concrete (kg/m3){Non-air entrained} | First estimate of density of concrete (kg/m3){Air entrained} | | 10 | 2285 | 2190 | | 12.5 | 2315 | 2235 | | 20 | 2355 | 2280 | | 25 | 2375 | 2315 | | 40 | 2420 | 2355 | | 50 | 2445 | 2375 | | 70 | 2465 | 2400 |
| Recommended Slumps for Various Types of Construction (mm) |
|---|
| Concrete Construction | Slump Maximum | Slump Minimum | | Reinforced foundation and footings | 75 | 25 | | Plain footings, caissons, and substructure walls | 75 | 25 | | Beams and reinforced walls | 100 | 25 | | Building columns | 75 | 25 | | Pavements and slabs | 75 | 25 | | Mass concrete | 50 | 25 |
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