LEAK REPAIRING

1. Introduction

Water leaking often occurs in underground construction, basin, elevator pit, cracks in water pipes, cracks on terrace. Main reasons are as follows:

·  Lack of waterstop at construction joints

·  Spongy concrete

·  Large concrete structure is casted without expansion joints, causing cracks

·  Settlement and cracks on the concrete pipes.

Particularly, in the hydroelectric plants, leakage in construction joints of jet-drilling corridor, rooms inside the dam often originated from poor vibration, causing cracks and cavities in the concrete.

To overcome this hardness, we have studied repair materials and methods from Japan and focused on training of technical assistants who specialize in fixing water leakage, satisfying market demand.

Up to now we have made many projects nationwide, especially we have successfully treated the leakage the jet-drilling corridor at the largest hydroelectric plant in the North.

The aside movie describes leakage treatment process in the pure water pipe line of HCM City Water Supply Company, which was built in 1964. The crack is quite large (2m), water and gas keep spraying very strongly, the reason, which is reported by the Company, is due to overload vehicle passing.

2. Materials

We often use materials from Japan and from well-known chemical company on the world, some commonly used chemicals are as follows:

Quick-hardening cement to stop water temporary.

Epoxy resin E200 to form the water proofing firm.

Epoxy resin mixed with high strength sand 500 kg/cm² to patch the chipping positions.

Swelling substance – when sprayed into leaking position – will expanse 12-30 times in volume, filling up the void.

Epoxy E380, which is similar to sealing putty on the wall, adhesive under water, to form the final waterproofing layer.

For the heat-expansion joints and settlement joints in the hydroelectric plant, special materials will be applied so that leakage is treated while the expansion effect still ensured.