Guys, today let's talk about the highly controversial polyurethane grouting. This topic is quite sensitive, but we really have to discuss it.First, let's talk about whether drilling holes will damage the concrete structure.

The opponents think that drilling holes to one - half to one - third of the structure thickness, with a hole spacing of about 20 cm, and additional holes may be drilled if there is no grout output. This will definitely damage the concrete. However, the proponents believe that the cracks in the building already exist. Drilling holes at the edge of the cracks won't cause much damage, and grouting can also seal the leakage channels and strengthen the concrete.

Next, let's look at the grouting pressure. The opponents are worried that the pressure of the grouting machine, which can reach 60 - 70 MPa, can break the C30 - C40 concrete. The proponents say that although the grouting machine can reach such a high pressure, it may not be used. Low - pressure slow grouting is the right way. In fact, few concrete structures are broken on site. Only the concrete on the surface or with honeycombs and holes, or with a strength lower than C25, is not suitable for this method.

Finally, let's talk about the durability. The opponents claim that the polyurethane foam is prone to shrinkage, and the uneven settlement of the building can cause the foam to crack, leading to re - leakage.

The proponents point out that the shrinkage may be due to the use of water - based or oil - water mixed grouting fluids. We need to understand the differences between the materials and their application scenarios. Secondary grouting can also be used to solve the problem. Moreover, other grouting materials may not be spared either.Waterproofing and leakage repair can be rational.

What do you think? Let's chat in the comments.