After Cracks Appear in Prefabricated Slabs Inside the House

After cracks appear in the prefabricated slabs inside the house, if there are few cracks, the gaps are small, and there is no liquid flowing on the floor, no repair may be necessary; if the cracks are slightly larger and liquid is leaking, immediate repair is required, and drilling holes in the prefabricated slabs to avoid affecting the load-bearing structure should be avoided.

Handling When Cracks Are Small and There Is No Leakage

When there are few cracks in the prefabricated slabs, the gaps are small, and there is no liquid flowing on the floor, such cracks have little impact on the structural safety of the house and usually do not require repair. This is because smaller cracks generally do not cause substantial damage to the overall load-bearing capacity and stability of the prefabricated slabs and do not endanger the structural safety of the house. However, even so, it is necessary to regularly observe the changes in the cracks. If it is found that the cracks have a tendency to expand or increase in number, or other abnormal phenomena occur, such as slight subsidence or strange noises on the floor, further measures should be taken promptly.

Repair Steps When Cracks Are Large and There Is Leakage

1. Chiseling and Cleaning the Cracks: Chisel open the cracks in the slab joints, and chisel away 5 cm of the surface layers on both sides to make the joint surfaces sloped. At the same time, appropriately roughen the surfaces of the prefabricated floor slabs and the sides of the slabs to increase the bonding strength between the newly poured materials and the existing structure. After chiseling, carefully clean up the debris and dust chiseled off to ensure that the inside of the slab joints is clean and prepare for the subsequent repair work.
2. Applying Cement Mortar: Apply a layer of pure cement mortar inside the cleaned slab joints, with a water-cement ratio controlled between 0.4 and 0.5. The cement mortar can serve as a bonding and transitional layer, enabling the subsequently poured fine aggregate concrete to better combine with the prefabricated slabs.
3. Pouring and Tamping Fine Aggregate Concrete: Immediately pour and tamp the fine aggregate concrete, pouring it to half the depth of the slab joints for the first time. After the fine aggregate concrete absorbs water for a moment, conduct the second pouring and tamping until it is compacted and leveled 1 cm from the slab surface. Pouring and tamping in two batches can make the fine aggregate concrete denser, reduce internal voids, and improve the repair quality.
4. Curing: After the repair is completed, cure it for at least 2 - 3 days. During the curing period, stepping on it by others is strictly prohibited to ensure that the fine aggregate concrete can fully solidify and harden, achieving the expected strength and stability.

Construction Precautions

When dealing with cracks in prefabricated slabs, drilling holes in the prefabricated slabs should be avoided because drilling can damage the internal structure of the prefabricated slabs, affect the load-bearing structure of the floor slabs, and reduce their load-bearing capacity. If construction such as ceiling installation needs to be carried out on the prefabricated slabs, special attention should be paid to construction safety. Ensure that the hanging rods are installed in the joints between two prefabricated slabs to reduce the impact on the prefabricated slabs themselves.