Repair of superficial concrete damage

Shallow damages in old concrete may occur by contamination. As previously mentioned in the Concrete Diagnosis, it may also occur due to accidental impacts, abrasion, erosion or freeze/thaw cycles.

Common issues and queries you can face

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Freshly cast concrete

In the freshly cast concrete, superficial damages are revealed as honeycombs with exposed aggregates, pinholes or surface imperfections. In the case of honeycombs, imperfections are chiseled until the sound concrete is reached. Then, the surface should be cleaned from dirt, dust, paint, and laitance by grinding or air blowing. The surface should be dampened with water to surface saturated dry prior to any repair.

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Pinholes

In case of pinholes, the surface should be dampened with water to surface saturated dry prior to cementitious repair. In the case of using epoxy based products for repair, water should not be used on the surface in any circumstance. The area should be grinded in order to get rid of laitance, paint or any covering material, and then they should be cleaned with an air blower.

Step by step solution

weber solution

  1. Pinholes and surface defects

    weberep 360 FFR a premixed coating composed of very fine fillers and modified polymers. When mixed with clean water, using an electric mixer, it turns into a smooth paste. Applied to surface with a trowel, it provides a smooth and velvet-like finish that adjusts superficial irregularities with a thickness up to 3 mm.

    weberep FFC is a dry pre-mixed cementitious coating based on hydraulic binders, siliceous filler, water retaining agents and other admixtures. It is used as a render in one or two coats, on walls and ceilings in internal and external conditions. Apply the paste with a steel trowel. It should be allowed to partially set before smoothing.

  2. Honeycombs

    Honeycombs are formed when the concrete aggregates are exposed (but no exposed steel) with a thickness up to 20mm. In case of defects exceeding 20mm; it is considered a case of deep damage repair.

    Use weberep 350 NSG, a polymer modified non-shrink mortar to be mixed with the proper amount of clean water (according to TDS) until a homogeneous paste is obtained.

    Then apply by pressing with a trowel until cavities are fully filled. In case a compressive strength between 30 MPa and 50 MPa is requested, it is recommended to use weberep 332 FR instead.

    After its final setting, the repair product should be cured, either in the traditional way or by applying weberad cure WT or weberad cure Y40.