1. First, use a polisher to polish the 5 ㎝ width on both sides of the crack, and then clean the crack with acetone. There should be no oil stains, dust, etc. on the interface.
2. For superficial cracks with a depth of less than 5 mm, soak the epoxy resin with dilute liquid, dry and solidify, and then scrape the epoxy resin cement. The ratio of epoxy resin dilute liquid is epoxy resin: diluent: curing agent 1:0.4:0.25, which can penetrate deep into the root of cracks. Its structure is strong and can fill cracks.
3. For cracks with a depth greater than 5 ㎜, bury the grouting nozzle at a distance of 30-50 ㎝, and then seal the crack with epoxy resin cement, and the sealing width is not less than 5 ㎝. Epoxy cement seals cracks, one is to seal the superficial cracks, and the other is to prepare for grouting. The selection of the position of the buried grouting nozzle is particularly important, which should be determined according to the length, depth, direction, shape and other factors of the concrete crack. Generally, it is required to select points at both ends of the crack and the empty and solid parts to ensure that the slurry can reach each gap. parts, play the role of reinforcement and crack prevention.
4. After the epoxy resin cement is completely dry, a gas test should be carried out to check the integrity of the slurry inlet, liquid outlet and crack closure. Use 4 ㎏/㎝ 2 pressure air to input from the grouting hole. If the gas is output from the liquid outlet, and there is no air leakage at the sealant of the cement and the liquid outlet of other cracks, it means that the grouting port and the liquid outlet of the crack are set correctly, and the cement seal is reliable. , close the liquid outlet, increase the pressure in the crack to 4 ㎏/㎝ 2, keep the pressure for 2 minutes, if there is no air leakage, it is normal. If there is air leakage at the cement after ventilation and boosting, it should be re-sealed. If the air is discharged from more than 2 liquid outlets after ventilation and pressure increase, it means that the crack is connected to more than 2 cracks. At this time, the leaking liquid outlet should be closed until no air leakage can keep the pressure, and make records and marks. . After venting and boosting, there is no gas output from the liquid outlet. It may be that the crack channel is blocked during the sealing process of cement. At this time, the liquid outlet and grouting port should be added at the appropriate position of the crack in this section. , There is out, can maintain pressure, no leakage section.
5. After the gas measurement is qualified, the epoxy resin slurry is used for pressure grouting, and the air pressure for grouting shall not be less than 4 ㎏/㎝ 2.
6. When grouting, pay attention to observe the liquid outlet of the grouting nozzle. After confirming that it is full, close the liquid outlet of the grouting nozzle, increase the pressure to 4 ㎏/㎝ 2, keep the pressure for no less than 5 minutes, and then let it dry and solidify naturally , the natural drying time should be 72 hours
7. Check whether the crack repair is missing.
8. Remove the grouting nozzle and smooth the epoxy resin cement protruding from the surface of the concrete. 4. Conclusion After 20 days of construction, the crack repair project of Zhentou Bridge has been successfully completed. After actual inspection, the crack repaired by epoxy resin slurry has achieved the effect of increasing the strength of the arch ring.