Definition - What does Cement mean?
Cement is a dry powdery substance made by calcining lime and clay, mixed with water to form mortar or mixed with sand, gravel and water to make concrete. It is a binder material. Once hardened, cement delivers sufficient strength to erect large industrial structures.
Cement is corrosive to metals and therefore any metals in contact with cement should be corrosion resistant.
A normal type of cement that is used in the construction industry is also known as hydraulic cement because this powdery substance is generally mixed with water before use.
Corrosionpedia explains Cement
Cement is similar to mortar in that it sets extremely quickly and hardens after it has been mixed with water.
Any dry powdered cement is considered hydraulic because it sets and hardens after being combined with water. The product commercially referred to as hydraulic cement is usually a blend of Portland cement with certain additives that greatly decrease the setting time, allowing it to set and cure in wet conditions. These additives also prevent the mix from shrinking like normal cement, and some may actually expand slightly.
Cement should be applied over surfaces that have been cleaned and are free of oil, dirt, grease or any other contaminant that affect bonding with the permanent structure. It is recommended to undercut all areas on which the cement is to be applied.
Cement has the following advantages:
- Provides durable, long-lasting repairs
- Sets and hardens quickly, normally three minutes after being mixed with water
- Very easy to use
- Can be used on vertical applications
- Does not corrode or rust if corrosion resistant material is used
- Does not shrink
However a disadvantage could be that once mixed with water, cement only remains workable for 10 to 15 minutes. It also does not work on frozen surfaces or if the temperature suddenly drops dramatically low.
Using Metallization (Thermal Spraying) as Corrosion Prevention