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 15
th and until October
31
st
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 15
th 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.