The construction of high-pressure chemicalPolyurethane injection grouting shall be carried out by the construction team with professional training person and professional construction equipment.

　　Cleaning: check and analyze the leakage in detail, and determine the location and spacing of grouting holes. Clean up the necessary construction area, chisel off the concrete surface precipitation, to ensure that the surface is clean and wet.

　　Drilling: use electric hammer and other drilling tools to drill along both sides of the crack. The diameter of the drill bit is the same as that of the grouting nozzle (watertight needle). The drilling Angle should be ≤ 45° and the drilling depth ≤ 2/3 of the structural thickness. However, the interval between boreholes and cracks is not equal to 1/2 of the structural thickness (except for post-wall grouting). Drilling spacing is 20cm~30cm.

　　insert packers: install grouting nozzle (also known as watertight needle) Injection Packer in the well-drilled hole, and tighten it with special hexagon wrench, so that there is no gap between grouting nozzle and drilling hole, no water leakage.

　　Seam cleaning: use high-pressure cleaning machine to inject clean water into the mechanical packers at the pressure of 6Mpa, observe the outlet point, and clean the dust in the seam.

　　Sealing cracks: the surface of leaking cracks shall be sealed with cement-based waterproof material during washing cracks, so that the materials can not seepage when injecting Chemical Grouting Materials

　　Grouting: use high pressure Injection Grouting Machine to inject chemical grouting material into grouting hole. Elevation grouting sequence is bottom up; The plane can start at one end, one hole at a time. When the adjacent hole starts to grouting, maintain the pressure for 3~5 minutes, the grouting of this hole can be stopped, and the grouting of the adjacent hole can be changed.

　　Remove the packers : after grouting, remove or knock out the exposed grouting nozzle after confirming no leakage. Clean up the solidified spilled irrigation fluid.

　　Seal: repair and seal grouting surface with cement-based waterproof material.

　　Waterproof: Smear the chemical grouting position three times with a single component waterproof material (bottom, middle and surface) with a width of 10~20cm, and lengthen 20~30cm at both ends.

　　Introduction to chemical grouts technology

　　Concrete building crack is the main cause of concrete building damage, crack leakage is the most headache problem, because the cracks inside the concrete is completely ruleless. The general traditional plugging method is gouging the crack or leakage, and make surface plugging, but the result is here is blocked the other places begin to leak. Because the water in the internal cracks is moving irregularly, then seepage from the weak part of the concrete.

　　Chemical Grouts generally is inject chemical materials to the cracks of its structure by high pressure injection grouting machine and injection packers so as to achieve the purpose of waterproof, plugging, reinforcing and strengthening. It is often used to repair deep cracks in concrete structure. According to the grouting pressure and speed, it can be divided into high pressure quick grouting method and low pressure slow grouting method.

　　High-pressure chemical grouts technology is using the Injection Packers to generate the continuous high pressure , inject the chemical liquid into the cracks of the concrete, and completely squeeze out the water in the cracks, and completely fill the gaps, so as to achieve the purpose of water stop.