More stories about Repair

  • Accommodating radiant heat in slabs

    We are a ready-mixed producer in northern Wisconsin. Several contractors we supply have placed in-floor heating in garage or basement floors. Two of these floors have cracked after turning on the heat. We have been told that this may be due to thermal cracking or shocking. We would like information...

  • Too Little Cover

    We are continually running up against structural engineers who push the limits of the cover for rebar and post-tensioning cables for suspended slabs in concrete structures. We normally never like to work with rebar cover less than 1/4 inch above the aggregate size. We are finishing an underground...

  • Is it the Slab's Fault?

    A flooring contractor has experienced problems on four occasions over the years with his two-part polyurethane floor covering not bonding to our concrete slab-on-grade. He has said that the acid-etch process prior to installing the covering did not react very well with our slab surface, based on...

  • Measuring Crack Width in a Concrete Surface

    Our customer has asked us to help him evaluate some cracking that occurred on a recent pour of a large parking lot. We believe that the cracks are caused by dry shrinkage, but the owner is concerned that the cracks are structural in nature. We have agreed to monitor the cracks for a year or so to...

  • Cause of Cracks in Hollowcore Panel Topping

    We supplied 4x24-foot hollowcore slabs for a building floor that received a 2-inch-thick concrete topping placed by the concrete contractor. Part of the building was left unfinished for later use, and, when it was built out, the owner noticed a crack that was visible on the topping surface but not...

  • Mixes for Temporary Pavement Patches

    Last winter our company was asked by the city street department to supply concrete for temporarily patching some large sections of failed pavement during breaks in the cold weather. When the weather warmed up, the city permanently repaired the patches with hot-mix asphalt. We'd like to show that a...

  • Determining Causes of Concrete Cracking

    I do a lot of troubleshooting on residential concrete flatwork -- mainly sidewalks or driveways. Is there a way to tell the difference between structural cracking caused by overload or soil movement, and nonstructural cracking caused by volume changes related to drying shrinkage or thermal...

  • Test Your Safety IQ for Heavy Equipment Use