Can Prefabricated House Slabs Be Repaired?

Prefabricated house slabs can be repaired, but different measures need to be taken according to specific circumstances.

If cracks appear on the prefabricated house slabs, when the number of cracks is small, the gaps are narrow, and there is no liquid leakage, this situation has little impact on the structural safety of the house, and no repair may be required. This is because such tiny cracks usually do not cause substantial damage to the overall load-bearing capacity and stability of the prefabricated slabs, and will not affect the normal use and safety of the house.

If the cracks are slightly larger and there is liquid leakage, immediate repair should be carried out. The specific repair steps are as follows:

• Chisel open the crack seams: Use appropriate tools, such as an electric pick, to chisel open the seams at the cracks. The depth and width of the chiseling should be determined according to the actual situation of the cracks. Generally, it should ensure that the inside of the cracks can be fully treated and provide a good operating space for subsequent repair work.
• Clean the joint surface: Clean the dust, debris, and loose concrete on the joint surface after chiseling to ensure that the joint surface is flat, firm, and clean. This allows the repair material to bond better with the original structure and improves the repair effect.
• Brush pure cement mortar: Brush a layer of pure cement mortar on the cleaned joint surface. The cement mortar should be evenly mixed and applied evenly with an appropriate thickness. Its function is to enhance the bonding force between the new and old concrete.
• Pour and compact fine aggregate concrete and cure it: After brushing the cement mortar, promptly pour and compact fine aggregate concrete, fill the fine aggregate concrete into the cracks and the chiseled slab seams, and vibrate it to make it tightly combined with the original structure. After pouring, proper curing should be carried out to keep the repaired part moist. The curing time should generally be no less than 7 days to ensure the normal increase in the strength of the fine aggregate concrete.

In addition, if the prefabricated slab is broken, it needs to be evaluated by a professional institution. Professional reinforcement usually has the following three methods:

• Section enlargement method: Increase the cross-sectional area of the prefabricated slab by adding a concrete layer on its surface, thereby improving its load-bearing capacity.
• Stick carbon fiber cloth to the bottom of the slab: Carbon fiber cloth has the characteristics of high strength and light weight. Sticking it to the bottom of the prefabricated slab can effectively improve the slab's flexural resistance.
• Directly add beams and columns: Add beam and column structures below or around the prefabricated slab to share the load of the slab and enhance the overall structural stability of the house.