Industrial concrete tanks can be damaged if any of the liquid they hold leaks -- even if it's just water. As Andy Powell notes, a water leak in a concrete tank can lead to structural failures and sinkholes. Tanks are often protected with coatings, which most cement tank suppliers are able to provide. To be effective, however, tank coatings must be applied when the cement is completely clean. Here's why -- and how to tell if a cement tank is perfectly clean. 

Concrete Coatings Protect Concrete Tanks

In many ways, concrete is an excellent material to make industrial tanks out of. It's both inexpensive and strong. If not protected by a barrier, however, the liquids held in concrete tanks will leak through the tanks.

Concrete's a porous material, so liquids can seep into it. Some liquids used in industrial settings, such as oils and acids, can erode concrete quickly. Even seemingly benign liquids, such as water, will wreak damage if they freeze. As Making Wood Good details, water expands when it becomes ice. At it expands, it can crack concrete, which is inflexible.

Coatings prevent this deterioration from happening by not allowing the liquid in a tank to come into contact with the tank's cement floor, walls or top.

Contamination Causes Delamination -- And Leaks

Before a concrete coating is applied to a tank, the concrete surface being coated must be completely clean. If there are any contaminants, such as dirt, dust or even little concrete particles, they can prevent the concrete coating from properly adhering to the concrete tank. Just a small area that's not perfectly clean can cause a tank coating to delaminate from the tank.

If a coating begins to delaminate, the liquid being held in the tank can get in behind the coating. The liquid will then seep into the concrete tank and between the tank coating and tank. As it does, the problem will only worsen and become more acute. Soon, the tank, and possibly other property such as the ground near the tank, will be damaged.

Cleaning Methods Don't Check for Thoroughness

There are a number of ways to clean a concrete tank:

• shotblasting, which cleans concrete with steel shot
• scarifying, which cleans concrete by scarring its surface
• diamond grinding, which grinds the surface of concrete with a strong diamond

All of these methods can be effective ways to clean and prep a concrete tank to be coated. None of them, however, include a way to tell when the concrete has been thoroughly cleaned. Without a test, technicians must judge when a tank's surface is clean by just looking at it. If they make a mistake, which is easy to do because even small particles can cause delamination, a leak may develop and the tank might eventually be damaged.

A Water Spot Test Checks for Contamination

A water spot test provides a way to check for contamination on the surface of a concrete tank. Unlike the naked eye, a water spot test can find even the smallest remnants of contaminants. Best of all, this test is easy and inexpensive.

To perform a water spot test, lightly spray the top, sides and bottom of the tank with water. Watch whether the water seeps into the concrete or beads up. Anywhere that the water seeps in, the concrete is clean and free of contaminants. Anywhere the water beads up, the concrete hasn't been thoroughly cleaned. There is some contaminant between the water and concrete that's preventing the water from seeping into the concrete. Any place that still has contaminants should be recleaned, and then the water spot test should be readministered.

After completing this test, you'll have to let the tank dry out. This minor delay, however, is much easier to cope with than a leak caused by delamination. Because delamination can lead to costly property damage, it's worth taking a little time to use the water spot test to check for contaminants before applying a concrete tank coating.

For more information on tank coatings, contact a company like RSR Industrial Coatings Inc.