9.6 : תוספים מונעי מים ואנטי-בקטריאליים

Concrete takes in water due to the surface tension in the capillary pores of the cement paste, which draws in water through capillary action. Waterproofing admixtures are designed to block this absorption.

The effectiveness of waterproofing admixtures depends on the level of water pressure; it can be minimal, like rainfall, intermediate through capillary action, or substantial under hydrostatic pressure in water-holding structures.

Stearic acid and certain vegetable and animal fats are typical examples of such waterproofing admixtures mixed into the concrete and are different from water repellents.

Bacteria, fungi, or insects can harm concrete by causing steel corrosion and staining surfaces. The rough texture of concrete is suitable for bacteria to dwell and propagate, making surface cleaning inadequate.

This admixture might possess antibacterial, fungicidal, or insecticidal properties, like polyhalogenated phenols, dieldrin emulsions, and copper compounds.

The amount of antibacterial admixture added ranges between 0.1 and 10 percent of the cement's weight, but if the quantity is more than 3 percent, it can compromise the concrete's strength.