Cracks in concrete are quite common phenomena. Fortunately, Sika has a proven, high-performance solution for crack repair in newly-poured and refurbished concrete. Sikadur®-52 ZA, an injection or poured epoxy resin, provides a reliable seal for a wide range of structural or non-structural applications and uses such as joint and hole filling; crack and void sealing. Easy to mix and apply, Sikadur®-52 ZA is ideal for dry and damp concrete surfaces in horizontal and vertical locations.
Types of Cracks
These cracks may occur in reinforced concrete elements after the hardening state. Flexural cracks are vertical cracks that develop at the tension zone of the member up to their neutral axis. Width of these cracks are usually wider at the mid-span of the member. This is because the maximum strain in reinforcement occurs at this
zone.
Drying shrinkage is also a crack that occurs after hardening of concrete. It happens due to the reduction of concrete volume when the water content in the concrete evaporates. As the water content increases, the rate of shrinkage rises equivalently. Drying shrinkage may be a full-length cracking. Usually contraction joints are placed to predetermine the drying shrinkage. This cracking will be in the form of transverse, pattern or map cracking. Width of these cracks are usually wider at the mid-span of the member. This is because the maximum strain in reinforcement occurs at this zone.
Concrete will contract and expands with changes in moisture and temperature. As long as these contraction movement is free to take place tensile stress will not develop in concrete members. But in reality, movement of this contraction will be restrained due to internal or external restraints, which causes development of tensile stress, leading to cracking.
Thermal cracking occurs during the hardening state. When cement reacts with water, heat of hydration is released from the cement, as a result thermal expansion occurs in the concrete member. Thermal crack possibly will be a full depth crack.
Plastic-shrinkage cracks are common in slabs. These cracks are comparatively short cracks. When the evaporation of the moisture at the surface of concrete is more than the availability of the rising bleed to fill the surface moisture, if this process happens before concrete attaining its tensile strength, the volume change may cause cracks.
Cracks can also be caused by alkali- aggregate reaction, sulfate attack, settlement cracking, freezing and thawing of saturated concrete, or corrosion of reinforcing steel.
Crack Repair Made Simple
Crack repair using Sikadur®-52 ZA couldn’t be simpler. The crack itself doesn’t need to be cut out or the area widened before filling. Sikadur®-52 ZA with its low viscosity permeates into the smallest of cracks to provide a permanent seal. Impermeable to liquids and water vapour, the system hardens without shrinkage a vital property when repairing cracks.
Taking Care of Most Construction Materials
As well as offering superb abrasion resistance and mechanical strength, Sikadur®-52 ZA provides excellent adhesion to most construction materials including natural stone, ceramics, fiber cement, mortar, bricks, masonry steel, iron and wood. It is the ideal concrete crack-repair solution for a wide range of infrastructure projects. Slabs, beams and columns found in buildings, bridges and the like are among surfaces ideal for the application of Sikadur®-52 ZA.
Sikadur®-52 ZA is also a successfully solution in the Wind Energy Industry. Wind Turbines need regular maintenance and repair and Sikadur®-52 ZA is an excellent solution of the concrete elements of the Wind Energy Turbines.
Prevention is Better Than Cure
The upkeep of our infrastructure is not only vital to maintaining elements such as nationwide bridges; neglecting to treat cracks in concrete structures sooner rather than later can lead to greater damage and costly, time-consuming repairs.
Prevention is better than cure, as the well-known saying goes, and so it is better to repair concrete when the damage is minimal with a reliable, robust, locally manufactured, solution such as Sikadur®-52 ZA, before greater problems take ahold.
Protecting the Future
To ensure areas that have been repaired are protected from future environment conditions, such concrete facades, column, soffits etc. are coated with anti carbonation coatings. Sika offers a range of coating solutions, which include water based crack bridging systems, resin coatings and hydrophobic impregnations. In buildings and infrastructure projects these protective systems are applied as part of the future repair and maintenance strategy.