Floor slab cracking is a very common phenomenon to come, this problem does bother many owners. Xinchor received many calls from customers, A new resident building had a cracked floor slab, the owner was worried that this crack would bring safety hazards to the house. The floor crack problem is divided into two situations, one is non-structural crack, which only need repair treatment, and the other is structural crack, which need to have reinforcement treatment.
Floor slab cracking is a very common phenomenon to come, this problem does bother many owners. Xinchor received many calls from customers, A new resident building had a cracked floor slab, the owner was worried that this crack would bring safety hazards to the house. The floor crack problem is divided into two situations, one is non-structural crack, which only need repair treatment, and the other is structural crack, which need to have reinforcement treatment.
Analyze the causes of cracking
(1) Due to the lack of construction measures and processes, cracks exceeding the allowability of the specifications occur on the surface of the concrete component or the weld of the steel structure.
(2) Excessive construction load, untimely maintenance of concrete, and premature demolition of the formwork cause cracks on the concrete surface that exceed the allowability of the specification.
(3) The use of concrete raw materials, admixtures and mix ratios is not strict, so that the concrete itself has defects and cracks formed.
There are two main types of concrete quality accidents:
(1) After reinforcement, repair and other methods, it can meet the design and specification requirements, such as honeycomb, hemp surface, cavity, exposed ribs, etc. after concrete pouring;
(2) The quality accident is very serious, how to deal with it can not meet the design and specification requirements, must be demolished and rebuilt.
For concrete that needs to be reinforced, the corresponding methods of “Technical Specifications for Reinforcement of Concrete Structures” and “Codes for design of reinforcement of concrete structures” are usually used for treatment
How are common cracks repaired?
(1) Surface sealing method: the use of fine independent cracks in the surface of concrete (crack width w≤0.2mm) or the capillary action of the mesh crack absorbs the repair glue with low viscosity and good permeability to seal the crack channel. For floor slabs and other parts that need to be impermeable, fiber composites should still be pasted on the concrete surface to enhance the sealing effect.
(2) Injection method: inject low viscosity, high strength crack repair glue into the crack cavity with a certain pressure; This method is suitable for the reinforcement and closure of independent cracks, penetrating cracks and honeycomb local defects of 0.1mm ≤w ≤ 1.5mm stationary. Before injection, the perimeter of the crack should be sealed according to the instructions.
(3) Pressure grouting method: within a certain period of time, the grouting material repairing the crack is pressed into the crack cavity at a higher pressure (determined by the product specification); This method is suitable for dealing with large structural penetration cracks, honeycomb-like severe defects in large volumes of concrete, and deep, meandering cracks.
(4) Filling and sealing method: Chisel out the U-shaped grooves with a width of not less than 20mm and 15mm respectively along the crack direction of the component surface, and then fill it with modified epoxy resin or elastic caulking material, and paste the fiber composite material to close its surface; This method is suitable for the treatment of active cracks and stationary cracks of w>0.5mm. After filling, its surface should be a protective layer.
How to choose a crack repair material
(1) Modified epoxy resins, modified acrylic resins, modified polyurethanes, etc. repair glue, including supporting synthetic resin repair materials such as primer, repair glue and polymer grouting, are suitable for the sealing and reinforcement of cracks, and can be repaired by surface sealing method, injection method or pressure grouting method.
The safety performance indicators of glue and grouting material for repairing cracks shall comply with the provisions of the current national standard GB50728. “Technical Specification for Safety Identification of Engineering Structural Reinforcement Materials”
(2) Flexible caulk sealant repair materials such as non-flowing silicone, polysulfide rubber, modified acrylate, polyurethane, etc., suitable for repair of active cracks and the sealing of dry shrinkage cracks at the seam interface of concrete and other materials.
(3) Ultra-fine non-shrinkage cement grouting material, modified polymer cement grouting material and non-retractable micro-expansion cement, etc. inorganic cementitious cement materials repair materials, suitable for the repair of stationary cracks greater than 1.0mm.
(4) Alkali-free glass fiber, alkali-resistant glass fiber or high-strength glass fiber fabric, carbon fiber fabric or aramid fiber and other fiber composite materials and their suitable adhesives, suitable for the sealing and strengthening of crack surfaces.
Advantages of XINCHOR Crack Reparing Grouting Adhesive CrackChor 410
Epoxy resin as the main raw material, low viscosity, strong permeability, easy to apply; No shrinkage, impact resistance; Corrosion resistance, aging resistance;
It can effectively resist the intrusion of media that induces steel corrosion and prolong the service life of the structure;
Maintain the integrity of structures and components by reinforcing concrete;
Restore the use function of the structure and improve its waterproof and anti-seepage capabilities;
Improve the appearance of the structure.
