Q&A

Frequently Asked Concrete Questions for our customers.

What’s the difference between cement and concrete?

Cement is an ingredient in concrete, much like flour is an ingredient in bread. Dry, powdered (Portland) cement is blended with sand, stone and water to produce concrete.

Why does concrete crack?

Concrete, like all construction materials, contracts and expands under various conditions of moisture and/or temperature. Cracks may be caused by movement of the ground, or heavy loads (like trucks). The lack of proper curing and control joints will contribute to random cracking.

When can I drive on my new driveway?

As a rule of thumb, in the summer, a new concrete driveway may be opened to cars (not trucks) after seven days (WE RECOMMEND 10 days). In cool weather, wait an additional seven days.   We suggest concrete driveways not be constructed in the winter, unless EXTREME protective measures are taken to prevent damage. The best time of year in Chicago land to construct a driveway is after April 15th and until October 31st each year.

What is curing concrete?

Curing means maintaining satisfactory moisture content in concrete for a long enough time during its early stages so that its desired properties develop. Adequate curing provides additional strength and durability. Concrete cured for three days will have only 66% of the strength of concrete cured for 28 days.

How big is a cubic yard?

A cubic yard of concrete measures three feet by three feet by three feet, or 27 cubic feet. It will weigh about 4000 pounds. It will cover an area of 81 square feet when placed four inches thick.

What is air-entrained concrete?

When we want our concrete to be watertight and durable while being exposed to freezing and thawing, we add a small amount (6%) of microscopic air bubbles into the mixture. These bubbles provide expansion space for water that may saturate the concrete, freeze and expand. Air-entrained concrete should be specified for exposed (outside) concrete.

How thick should the new concrete be?

A minimum of four inches is generally enough for a residential driveway or garage floor that will be used by cars and light trucks only).  If a parking area will be used by both cars and medium to heavy trucks, the slab should be six inches thick. Frequent use by heavy trucks may require a slab six to eight inches deep.

Do I need reinforcement wire?

Since all concrete cracks, the wire mesh can be placed in your slab to prevent heaving concrete if the ground surface below shifts or settles unevenly.

Can I use salt on my driveway and sidewalk?

Owners should not use salt during the first winter, especially if the concrete was placed after September 15th and not sealed.  We suggest the use of sand instead.  Don’t allow snow and ice to accumulate on the slab during the first year.

What is a safe Deicer?

Deicers containing salt and/or calcium chloride should be generally safe for use on quality concrete pavement after the first winter. Never use any deicer that contains either ammonium sulphate or ammonium nitrate. Anyone who buys a deicer under a brand name should read the label to see what it contains.

What is concrete sealers?

Water repellent coatings and sealers can help prevent damage from freeze/thaw cycles and the intrusion of deicing salts. They keep water from getting into the surface pores. Just as we regularly paint homes and buildings, we should seal concrete routinely to protect it from moisture and prolong its life.

Why must I worry about eaves trough placement around my driveway?

Excess water around the concrete causes the most damage in the spring when the warm day temperatures and freezing nights cause the concrete to heave if water is present under the slab.  You must allow for proper drainage around concrete work.   Do not allow drain water to undermine the concrete slab and cause settlement cracks.

When can I walk on my resurfaced concrete?

It depends on the square footage of the resurfaced concrete.  For larger surfaces such as driveways and gangways (sidewalks) it usually takes 2 days for the epoxy to dry.  For smaller areas it takes about 24 hours.

 

 

If you have more questions please e-mail us.