Water proofing admixtures specialized in preventing concrete from water penetration. Concrete absorbs water, because there are capillary suctions within the hydrated cement paste that form due to surface tension in the capillary pores. How active water proofing admixtures are? It depends on the applied intensity of water pressure i.e., either it is low water pressure or high water pressure.
The main purpose of water proofing admixtures is to make concrete hydrophobic. If the contact angle between the walls and the water is increase then it pushes water out from the capillary pores.
Water Proofing Methods
Water proofing admixtures achieve their aim by various three methods;
- Water proofing admixtures reacts with calcium hydroxide. Calcium hydroxide is the compound of cement paste and make concrete hydrophobic. Animal fats, stearic acid and some vegetables are the example of such kind of admixtures.
- Second method of making concrete hydrophobic is by contacting cement paste with the coalescence. Coalescence is an alkali by nature. Alkalinity property of coalescence breaks down the emulsion.
- In the third method, some fine materials are used that form a coating over the surfaces. Fine materials should also comprise of some hydrocarbon resins or coal tar pitches or calcium stearate. These compounds form the hydrophobic coating over the surface. It is very difficult to completely coat the entire surfaces. Therefore, complete waterproofing of a surface is unlikely to be achieved.
Waterproofing Admixtures Extra Benefits
There are some extra benefits of water proofing admixtures.
- The first major benefit of waterproofing admixtures is on the workability of concrete. They improve the concrete workability. This happen, because of the presence of bituminous emulsion in waterproofing admixtures that entrain air in the concrete mix.
- Water proofing admixtures also improves the concrete cohesion property.
Waterproofing Admixtures Tips
The two major beneficial tips of waterproofing admixtures are;
- Before using water proofing admixtures, one must be sure that it not contains any chloride. If chloride containing admixture is used, then it helps corrosion of concrete.
- Waterproofing admixtures and water repellent admixtures are not the same thing. These are two different admixtures. Water repellent admixtures are composed of silicon resins and these are applied to the concrete surfaces. While, water proofing admixtures are based on emulsion. It provides a strong film coating over the surface with elasticity.