THE FACTS ABOUT CONCRETE
In an effort to educate our customers, Liberty Ready Mix would like to ask you to read the following information. Concrete is one of the biggest investments that home and business owners can make, and protecting that investment should be as important to you as it is to them.
Click each link to download a pdf to learn more about the following information:
Dusting Concrete Surfaces
Scaling Concrete Surfaces
Crazing Concrete Surfaces
Cracking Concrete Surfaces
Plastic Shrinkage Cracking
Joints in Concrete Slabs on Grade
Cracks in Concrete Basement Walls
Curing In-Place Concrete
Hot Weather Concreting
Finished Concrete Flatwork
Curling of Concrete Slabs
Delamination of Troweled Concrete Surfaces
Loss of Air Content in Pumped Concrete
Jobsite Addition of Water
Cold Weather Concreting
Concrete Slab Moisture
Vapor Retarders Under Slabs on Grade
Thermal Cracking of Concrete
Proper maintenance and care during the first cold weather season is critical to minimizing damage to ANY exterior concrete flatwork installed within the past year. This includes driveways, sidewalks, porches, patios and even garage floors.
WHAT CAUSES CONCRETE FLATWORK DAMAGE?
Freeze/thaw cycles during cold months are the most common cause of damage to the surface of concrete flatwork. Concrete is a porous material that will absorb moisture at the surface. When the absorbed moisture freezes, in exerts a tremendous expansive force, which weakens the surface and sometimes leads to scaling. Concrete less than one year old, and particularly concrete poured after November 1st, is particularly vulnerable to freeze/thaw cycle damage.
FACTS ABOUT DE-ICING PRODUCTS
De-icing products can be composed of a variety of different chemicals that are harmful to concrete. State, county and municipality street departments frequently use magnesium chloride based materials in the past, a chemical that exacerbates the probability of damage to concrete as a result of snow and water drippings from vehicles.
THE MOST DAMAGING EFFECT OF USING DE-ICERS IS NOT THE CHEMICALS THEMSELVES, RATHER THAT THEY INCREASE THE NUMBER OF FREEZE/THAW CYCLES EXPERIENCED BY FLATWORK DURING COLD MONTHS.
Repetitive cycles amplify the weakening effects caused by freezing moisture at the surface of the concrete. As a general rule, de-icing products should not be applied to exterior concrete flatwork that is less than one year old.
Liberty Ready Mix prides itself on providing quality products to its customers. We use concrete mixes for exterior flatwork that meet or exceed industry standards for compressive strength and air-entrainment. Air-entrained concrete mixes contain tiny air bubbles that provide spaces within the concrete for expanding water to move into, thereby reducing the expansive stresses associated with freezing moisture in the concrete.
PROTECTING YOUR EXTERIOR FLATWORK
You should inform all of your customers to take the following precautions. This will help to reduce the number of call backs that you get, in turn reducing tear-out and replacement losses.
• DO NOT USE ANY DE-ICING PROCUCTS IN THE FIRST COLD WEATHER SEASON UNDER ANY CIRCUMSTANCES. Again, using these products exacerbates the weakening effects of freezing moisture on concrete surfaces by increasing the number of freeze/thaw cycles.
• NEVER USE ANY DE-ICING PRODUCT CONTAINING AMMONIUM NITRATE, AMMONIUM SULFATE, OR MAGNESIUM CHLORIDE. These agents chemically attack concrete and cause damage above and beyond the effects of freeze/thaw cycles.
• DO NOT PARK VEHICLES ON DRIVEWAYS. Snow and water contaminated with road salt and de-icers will drip from vehicles leaving concentrated areas of salt or de-icer brine that will facilitate multiple freeze/thaw cycles at the surface of the concrete.
• MINIMIZE VEHICLE TRAFFIC ON THE DRIVEWAY UNTIL COLD MONTHS HAVE PASSED FOR ANY CONCRETE POURED AFTER NOVEMBER 1. Concrete requires an ambient temperature of 50 degrees of 30 days for the curing process to complete. If the ground is frozen, as it often is after November 1, the compressive strength of concrete is at a minimum. A weak concrete surface combined with uneven areas of frost-heaved sub-base can lead to severe damage when subjected to the stress caused by the weight of an automobile.
• APPLY A PROTECTIVE SEALER TO THE SURFACE OF THE CONCRETE. Liberty Ready Mix would be happy to assist you with more information about sealers and their application.