Bian Xiao sorted out the relevant contents of external wall crack treatment through the architectural knowledge column of the construction industry encyclopedia website Construction Network. The basic situation is as follows:
Causes of cracks in external walls of buildings;
1. Shrinkage crack: it is caused by the change and shrinkage of materials, and it is generally reticulate on the wall, and two different materials may be formed at its interface;
2. Temperature cracks: caused by thermal expansion and cold contraction deformation, generally horizontal cracks along the ring beam of the top floor (flat roof), vertical cracks along the window angle, diagonal cracks along the window angle or internal longitudinal wall (multi-end, large, basically without middle); There is also an interface attached to the wall along the chimney;
3. Settlement cracks: inclined cracks in the wall caused by uneven (differential) settlement of the foundation; Upper horizontal crack caused by pulverization and compression of mortar joint; Vertical cracking of reinforced concrete beams caused by bearing settlement.
4. Deformation cracks: cross cracks on the wall caused by deformation; Vertical cracks in vertical and horizontal walls; Fracture caused by inclination, etc.
5. Structural cracks: also called load cracks caused by load, such as multiple vertical cracks in the wall column under the beam; Transverse horizontal cracks, oblique cracks and circumferential vertical cracks in the middle of the beam slab; Shear oblique crack at bearing edge; Transverse cracks in tensile members, etc.
Basic situation of external wall crack treatment:
Cracks caused by temperature changes are difficult to repair, but there is no danger of house collapse. In order to avoid this kind of crack, it is necessary to solve the problem of linear expansion difference between roof and brick wall. The common method is to keep the roof warm.
Due to cracks caused by insufficient masonry stiffness, brick walls will bend in the plane, and horizontal cracks often appear at the midpoint of the bending length. In this case, reinforcement measures should be taken. Pressure grouting can be used to inject pure cement slurry into cracks, and then measures such as adding wall columns or strengthening the wall between windows can be taken.
Cracks occur due to insufficient masonry strength, and the wall with such cracks is in danger of collapse. Take reinforcement measures. Generally, pilasters are added or reinforced with steel structures.
The location and trend of cracks in brick walls due to uneven settlement of foundation are different from those in wall columns due to insufficient strength and stiffness. In other words, cracks caused by uneven settlement of foundation will not cause strength or stiffness problems of wall columns. After the settlement is stable, it should be repaired with cement mortar.
If the rigidity and strength of wall column members and building structures are sufficient, the cracks in the wall caused by uneven settlement of foundation need not be reinforced, but only repaired.
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