C.K.R. Construction, L.L.C.
Your Concrete Source

C.K.R. Construction, L.L.C.
COMMON QUESTIONS & ANSWERS


What is the difference between Cement and Concrete?
The Portland Cement Association says although the terms cement and concrete often are used interchangeably, cement is actually an ingredient of concrete. Concrete is basically a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement. Concrete gets stronger as it gets older. Portland cement is not a brand name, but the generic term for the type of cement used in virtually all concrete, just as stainless is a type of steel and sterling a type of silver. Cement comprises from 10 to 15 percent of the concrete mix, by volume. Through a process called hydration, the cement and water harden and bind the aggregates into a rocklike mass. This hardening process continues for years meaning that concrete gets stronger as it gets older.

So, there is no such thing as a cement sidewalk, or a cement mixer; the proper terms are concrete sidewalk and concrete mixer.
Source: THE CONCRETE CENTRE.

NO SALT . . . EVER!
Yes, salt damages concrete. Concrete is one of the longest lasting surfaces that you can use if poured and finished correctly, but it is also a porous substance and absorbs water. When you spread de-icers or salt onto your concrete, the salt melts the snow. As the salt melts the snow, the concrete absorbs the water. While all of this is going on, the salt is attracting more water because it is a hygroscopic. (Hygroscopy is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption.) So, now your concrete is absorbing all this salt water, and when the temperature drops and the water freezes, the ice crystals inside the concrete starts tearing it apart.

Even if you don't spread it on your driveway, city trucks and road crews use salt to help keep the highways safe, and this WILL be brought in on your tires and drip smugly onto your concrete garage floor. If you use salt on your driveway, shaling will begin and your driveway will eventually look like a flaky, crumbling ancient ruin!

How do I Keep My Driveway Clear of Ice and Snow?

Annoyingly so, keeping a car clean during the winter months is nearly impossible. However, if you can wash it occassionally, especially with undercarriage car washes, this will certainly help keep salt buildup to a minimum. A concrete maintenance program is also recommended to keep your driveway and sidewalks sealed.

Salt truck - Damage concrete

As for melting the ice off of your concrete? Be careful, most de-icers contain salt and will damage concrete. Sand or kitty litter is the best solution, as it is not aggressive toward concrete yet still provide traction to keep you and others from falling.

What is Curing Concrete?
Curing is one of the most important steps in concrete construction, because proper curing greatly increases concrete strength and durability. Concrete hardens as a result of hydration: the chemical reaction between cement and water. However, hydration occurs only if water is available and if the concrete's temperature stays within a suitable range. During the curing period-from five to seven days after placement for conventional concrete-the concrete surface needs to be kept moist to permit the hydration process. new concrete can be wet with soaking hoses, sprinklers or covered with wet burlap, or can be coated with commercially available curing compounds, which seal in moisture. Source: Portland Cement Assoc.


Why Does Concrete Crack?
All concrete will crack. Concrete shrinks as it dries and cures. On average, a concrete slab shrinks 1/16th inch for every ten linear feet. What this shrinkage does is produce significant internal stress within the slab. This stress or force is considered a tension-type force as the concrete is trying to pull itself apart, much as you pull on two ends of a piece of newspaper. Pull hard enough and the paper tears. Put creases in the paper and it tears down the crease lines.

Concrete masons can do the same thing by creating a line in concrete slabs as they are finished or immediately after they are poured. A saw cut or tooled line that creates a groove in a slab actually reduces the thickness of the slab at that location and makes it easier for the slab to crack. In the trade these lines are called control joints placed specifically to control where the crack will occur.

"The reason that contractors put joints in concrete pavements and floors is to allow the concrete to crack in a neat, straight line at the joint when the volume of the concrete changes due to shrinkage." PCA

Most cracking can be prevented by using wire mesh and rebar during the set up phase. The Portland Cement Association (www.cement.org) and the American Concrete Institute (www.concrete.org) agree that the minimum depth of a control joint should be 1/4th the thickness of a slab.

What Do you Mean by "Decorative" Concrete?
Decorative has become very popular over the years because of its pleasing aesthetics. The right stamp pattern and color can turn your driveway, pool deck or business showroom floor into a work of art.

Decorative concrete can give the appearance of natural rock or tile, but doesn't have the high installation and maintenance cost. It is also not as prone to scaling from the freeze thaw/salt relationship because it is finished off with a higher-grade sealer. Tis sealer helps keep the salts from penetrating the surfaces and becoming a problem.



 

I've heard of "Concrete Maintenance" services. I didn't know concrete needed maintenance. What is that?

Concrete Maintenance is a program recommended for anyone who wants to preserve the beauty and integrity of their concrete. Contact Chance at 913.963.0062 to learn more.

Resources:
The Portland Cement Association
The Concrete Centre

For more information, contact Charles "Chance" Ragan at 913.963.0062 for a free estimate and evaluation.