Cracks Between Prefabricated Slabs in New Houses
There are cracks between the prefabricated slabs in new houses, and the treatment method needs to be determined based on the nature of the cracks. Normal cracks do not require excessive concern, while abnormal cracks need to be dealt with promptly.
Normal Crack Situations
It is normal for there to be cracks between prefabricated slabs. When the concrete solidifies, the evaporation of water generates shrinkage cracks, which are thinner than a hair strand. Temperature changes can also cause cracks to appear, similar to how expansion joints are left in railway tracks. These cracks are safe and usually do not pose a threat to the structural safety of the house, so no special treatment is required.
Abnormal Crack Situations and Treatment
If the crack exceeds 0.3 millimeters, keeps widening, or runs from the top to the bottom of the entire slab, and may be accompanied by wall tilting, steel bar rusting, etc., this is an abnormal crack and must be taken seriously and dealt with promptly. The specific treatment steps are as follows:
- Surface Treatment: Use a wall planer to plane off the surface plaster by more than 10 centimeters and chisel out an inverted V-shaped opening. The purpose of this step is to enlarge the crack opening to provide better adhesion for the subsequent filling material. Then, use a blower to clean the dust to ensure the inside of the crack is clean and prevent the dust from affecting the bonding effect of the subsequent materials.
- Leveling Treatment: Use a repair adhesive to level the crack. For uneven areas, use an angle grinder to polish until flat. The repair adhesive can fill the crack, restore the surface to flatness, and provide a good foundation for the subsequent粘贴 (pasting, here it should be 'sticking') of carbon fiber cloth.
- Sticking Carbon Fiber Cloth: After leveling, apply carbon fiber impregnating adhesive. First, apply a layer of adhesive at the bottom and then stick the carbon fiber cloth. During the sticking process, use a glue scraper to scrape out air bubbles in the same direction to avoid the occurrence of voids. Voids will affect the bonding strength between the carbon fiber cloth and the prefabricated slab, reducing the reinforcement effect. Finally, apply modified epoxy impregnating adhesive on the surface to further enhance the bonding performance between the carbon fiber cloth and the prefabricated slab and improve the load-bearing capacity of the crack area.
If you are unsure about the nature of the cracks and the treatment method, it is recommended to contact a professional agency promptly for inspection and treatment to ensure the structural safety of the house.
