 | Justin Crain is VP / Treasurer of American Concrete Co., Inc., which is owned by his parents, Dennis and Jane Crain. American Concrete is celebrating its forty-first anniversary and Justin is the third generation to be involved with the family company. American Concrete was awarded the 2011 Pittsburg Area Chamber of Commerce Small Business of the year award. Justin is currently the President of the Kansas Ready Mix Concrete Association and is currently on the board of directors for the Mount Carmel Foundation as well as the Pittsburg Public Library Foundation. Please visit our website, www.americanconcreteco.net, or call 620.231.1520. |
Concrete
2012-03-27 09:58:38
What is concrete crazing?
Q: What is concrete crazing?
A: Crazing is the development of fine random cracks across the surface of concrete or mortar, caused by the shrinkage of the surface layer. These cracks are sometimes referred to as shallow map or pattern cracking due to the appearance of the spider web network of cracks. The cracks are rarely more than 1/8 inch deep and usually most noticeable on steel-troweled surfaces.
Crazing develops early in the life of the concrete, and usually apparent the day after placement or within the first week.
There can be several causes, including:
• Poor or inadequate curing
• Adverse environmental conditions
• Too wet mix
• Finishing operations performed while bleed water remains on the surface
• Sprinkling cement on the surface to dry bleed water
In order to avoid crazing, start curing as soon as possible. Use moderate slump, or 3-5 inches of concrete. Do not sprinkle cement to soak up the bleed water. Finally, when you expect high evaporation rates, slightly dampen the subgrade prior to placement.
Getting a good surface on cement can be difficult and involves careful attention and precision timing. Concrete professionals can help assure that your surface is free of crazing and ready for you to use and enjoy.
