Category: How To

  • Pop-Outs in Concrete

    Pop-Outs in Concrete

    Pop-outs Diagnosis: Also known as rock-pops, they are small cone-shaped pieces of a concrete surface that separate due to focused internal pressure. Small pop-outs leave holes up to 0.4 in. (10 mm) in diameter; medium pop-outs leave holes 0.4 to 2 in. (10 to 50 mm) in diameter; and large pop-outs leave holes greater than […]

  • Dusting

    Dusting

    Dusting is the development of a soft, powdery material that can be easily rubbed off the surface of hardened concrete Diagnosis: Appearance of a powdery substance on the surface of the concrete that rubs off easily. Cause: There are multiple potential causes for this condition, such as beginning finishing operations while bleed water is still […]

  • Alkali-Silica Reaction

    Alkali-Silica Reaction

    Alkali-Silica Reaction (ASR), the reaction between alkalies in portland cement and certain siliceous rocks or minerals Diagnosis: An expansive cracking condition with discoloration. Cause: A chemical reaction between the naturally occurring sodium and potassium in Portland cement and certain silicaceous minerals. This reaction causes the expansion of these aggregates initially and as the reaction continues, […]

  • Blowup

    Blowup

    A blowup is a localized upward movement of a concrete curb or slab, usually at a joint or crack. Diagnosis: Cracking and subsequent deviation from the straight plane of a concrete element due to forces imposed by thermal expansion. Cause: The thermal expansion of concrete is around 5.5 millionths of an inch per degree Fahrenheit. […]

  • Curling

    Curling

    Curling of Concrete Slabs Diagnosis: Also referred to as edge-curling, it’s the lifting of a slab or topping at its corners and/or edges. You’ll see cracks or deterioration around the perimeter edge, and a noticeable up-lift at perimeter edge when checked with a straightedge. Cause: Dimensional differences between the slab surface and sub-surface caused by […]

  • Delamination

    Delamination

    Delamination of Concrete Diagnosis: Delamination is a separation, splitting or de-bonding of the concrete’s thickness along a plane parallel to the surface. Spotted visually if the deterioration is advanced or audibly by tapping the area with a hammer, dragging a piece of steel chain across the surface, or using a specially designed roller tool. Cause: […]

  • Honeycombing

    Honeycombing

    Concrete Honeycombing Cause: Failure of the cement paste to consolidate and fill the voids between the more coarse aggregates. Possible concrete repair solutions: Functional/aesthetic concrete only: Chip by hand to remove any loose material SSD (saturated, surface dry). This is the process of saturating the concrete substrate to receive a topping or patch with water […]

  • Plastic Shrinkage Cracking

    Plastic Shrinkage Cracking

    Plastic Shrinkage Cracking in Concrete Materials Cause: Plastic Shrinkage Cracking occurs as a result of very rapid evaporation of the concrete while it is still in a plastic state. Hot, dry, and windy environmental conditions and lack of countermeasures employed. Prevention: Timing the pour during cooler temperatures (evening or early morning) Providing temporary shelter from […]

  • Concrete Crazing

    Concrete Crazing

    Crazing Diagnosis: Random fine cracking on the surface resembling cracked mud on a dried up pond, but in a smaller pattern. Prevention: Any concrete or masonry surface can be subject to crazing. It can result from tension developed at the surface of the concrete formed during curing that is greater than that developed below the […]

  • Bug-Holes in Concrete

    Bug-Holes in Concrete

    Bug Holes Diagnosis: Also known as blow-holes, bug-holes are small air-bubble voids on the surface of formed concrete. Cause: Air entrapped during concrete placement and consolidation. Three main factors contribute to this condition, improper vibration practice, non-permeable formwork and mix design. To prevent bug holes, follow the ACI (American Concrete Institute) published vibration practice standards, […]