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    Efflorescence: Causes and Solutions

    A look at what causes efflorescence and how it can be removed.

     
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    Concrete's Air Content

    Producer solves air content variations in its exterior mixes.

     
  • While they are unsightly, popouts caused by deleterious near-surface aggregate particles or contaminants do not affect the function or service life of exterior flatwork.

    How to Minimize and Repair Popouts

    Popouts occur when small portions of the surface mortar break away from the flatwork.

     
  • The cracks are less than 0.04 in. wide and take away from the driveways natural beauty. The contractor already sealed some of them with clear silicone.

    How Common is Out-of-Joint Cracking?

    A contractor considers replacing a driveway after cracks appear.

     
  • Repairing Bugholes

    Bugholes commonly occur in vertical cast-in-place concrete.

     
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    Repairing Floor Abrasions

    Avoid scratching and gouging a polyaspartic floor coating.

     
  • Workers apply polyurea to the surface of a parking deck. There is a lot to consider before and during the application.

    Applying Polyurea Coatings

    Surface preparation is 80% of the job.

     
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    Craze Cracks

    These fine, random cracks on the surface of concrete are just aesthetic, not structural.

     
  • Poor bonding of the topping to the base course can be a primary reason for spalling. Bond coats can prevent this type of damage.

    Why Use a Bond Coat?

    Although the use of bond coats is usually a matter of preference, a number of industry organizations recommend using them.

     
  • Although different, water- and solvent-based sealers both result in a sealed concrete surface.

    Water- Versus Solvent-Based Sealers

    Knowing the differences between various sealers will help you determine which one is right for your job.

     
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    Selecting and Using Bond Coats

    Using the wrong bond coat is a major reason for failing to join two concrete surfaces.

     
  • Concrete sealers enhance a floor and protect it from moisture, abrasions, and other defects.

    Finding the Right Sealer for the Job

    No single concrete sealer is appropriate for all projects. They are chemically different and are designed for different purposes.

     
  • Blistering on tilt-up surfaces shortly after it rains is likely caused by not removing the mold release agents and bond breakers used for casting the concrete component.

    Coating Tilt-Up Concrete Walls

    Procedures for coating concrete surfaces are different from other surfaces, and tilt-up surfaces require special preparation.

     
  • Accumulating dirt, dust, and other debris on exterior concrete surfaces can resemble mildew. Dirt pickup cannot be eliminated entirely, but the best elastomeric wall coating formulations use resins that deliver excellent dirt pickup resistance without sacrificing elongation. Look for a product that indicates good dirt pickup resistance.

    Preventing Cracks in Walls

    Elastomeric wall coatings bridge concrete surface cracks and hide them from view.

     
  •  At left, an unmodified patch is easily dislodged due to a lack of hydration during curing and lack of adhesion. At right, a modified patch at 10% polymer (percent polymer by weight to cement) would not budge.

    Polymer-modified Mortars

    It helps to understand some of the basics about why polymers are added to cement formulations.

     
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    Meeting VOC Regs

    Since I began sealing concrete floors years ago, the EPA has adjusted its rules several times. It seems VOC levels for concrete sealers are constantly changing. What do I need to know if I work in different areas?

     
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    Grinding and F-Numbers

    Our business has become more focused on polishing concrete retails floors, and we are concerned how grinding and polishing affects a floor's flatness and levelness. How can we be sure we are meeting the correct specifications? Do any studies exist showing the effects on FFand FL numbers?

     
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    Predicting Windy Day Problems

    We are planning to bid on a decorative patio on a high-profile project overlooking the Pacific Ocean. The area is known for its continuously changing weather and especially windy conditions. We would like to try to estimate how the varying weather conditions will affect our productivity. We would...