Hydraulic cements find particular use in places where quick setting is desirable. Typically hydraulic cements will set in about 5 minutes even when there is water flowing and is in direct contact with the cement mixture. Hydraulic cements are not substitutes for Portland cement that we use for building homes. In homes they find use in sealing leaking concrete tanks with water in it. They can also be used for sealing small cracks in tank walls. They are to some extent used in laying foundations for bridges and underwater structures.
Commercially manufactured hydraulic cements are actually a combination of hydraulic cement and other chemicals. There are different varieties of hydraulic cements you can buy with each having different setting times. The advantage of hydraulic cement is it is not corrosive, won’t rust and won’t shrink either. The last property is what makes it ideal for sealing masonry walls and concrete structures.
The principal ingredient in hydraulic cement is calcium silicate with calcium sulfates as well. Calcium compounds it may be remembered are good waterproofing materials. When water is mixed to hydraulic cement a chemical reaction takes place and results in the formation of chemical compounds. These compounds intensify hardening of the material rapidly which is the reason why they set so quickly. Hydraulic cement is also used in underwater structures in harbors and bridges.
Hydraulic cement is also used in places where rainfall is heavy. Prolonged contact with water hardly affects the cement’s strength which is a distinct advantage. Most hydraulic cements are branded. DRYLOK is one of the better known brands of hydraulic cements. DRYLOK is also sold as DRYLOK Fast Plug and is ideal for home use. It finds use in sealing cracks in walls and in sealing.
Preparing the surface before using DRYLOK Fast Plug is important. If there is a small crack you may have to widen it a bit to accommodate the cement. Once the crack has been prepared, you will have to mix an appropriate quantity of the cement with water and form a thick past which you can use it for plugging the crack. The mix will feel warm to touch and that is because of the chemical reaction taking place. Once that is done, the mix will set under 5 or lesser minutes. If you are using DRYLOK Fast Plug to seal a leaking tank with water in pressure, then, you should hold it with your palm for the time it is setting. This is a very important step, because, under pressure the mix may fall off.
It is important that you don’t mix more than the required quantity for a particular patch. DRYLOK Fast Plug sets so rapidly that you will not be able to use the mix another time. The normal quantity of water to use is 3 parts of DRYLOK Fast Plug to one part of water to get a putty-like consistency. Water should be approximately the same as room temperature – at lower temperatures the cement may take longer to set, which we don’t recommend.