Impact of surplus water in concrete mix
If there is too much water in a concrete mix, the concrete can be set smoothly but in this case, the quality of the overall product is reduced significantly.
Given below the effects resulting from the existence of excess water in a concrete mix :
a. Decrease in strength
b. Drying shrinkage
c. Loss of abrasive resistance
d. Rise in penetration
e. Dusting and scaling
f. Lowered stability
1. Decrease in strength: Compressive strength is the vital characteristic of solidified concrete and the excessive quantity of water lowers the compressive strength of concrete. The surplus water can?t make any contribution in the hydration process and this water is contained in concrete even after the concrete gets solidified.
This water is vaporized when susceptible to environment and various voids are created in the concrete which can contribute to decrease the compressive strength of concrete.
2. Drying Shrinkage: If the water-cement ratio is raised, the drying shrinkage and concrete turns out to be feebler in tensile strength and consequently, cracks will develop on the surface of concrete.
3. Loss of Abrasive Resistance: Abrasive resistance of concrete is directly relative to its strength. When the increment of too much water, the strength of the concrete is reduced and consequently, the abrasive resistance is also decreased.
4. Permeability: The concrete gets pervious after the vaporization of surplus water in solidified concrete. The resultant voids will soak up water and transform the concrete structure porous.
As we know, 1 m = 1000 mm
1 mm = 1/1000 m
1 mm2 = 1/10002 m2
5. Dusting: The surplus water in concrete mix takes the fine aggregate to the top, consequently, after solidification - a fine loose powder will be set to the top of the concrete surface. This method is known as dusting.
6. Scaling: Scaling of concrete is caused by the surplus water content in concrete. In this case, the top layer of the solidified concrete surface is detached. It occurs because of the reaction of water with freeze and thaw effects.
7. Reduced durability: The above-explained effects finally results in decreasing the durability of concrete. So, to produce durable concrete, water-cement ratio should be chosen perfectly. Low water-cement ratio facilitates to form more durable concrete. By including air entraining admixtures, the durability can be raised with low water content.