Pressure grouting method statement

Pressure grouting is method of injecting specially formulated cement based mixes under pressure to improve strength or reduce permeability of concrete structures.Cement grouting is usually performed by drilling holes into application area to intercept open cracks, joints, fissures or cavities, then pumping under pressure balanced and stabilized grout mixes using a combination of cement, water, and additives.Pressure grouting method is widely adopted and it is very successful in solving leakage problems.

Materials used for pressure grouting

1.     Ordinary portland cement

2.     non shrink grout

3.     potable water

Tools and tackles used for pressure grouting

i) Air compressor with a capacity of 3 to 4 cum/ per minute and with a pressure of 3 to 5 kg per sq.cm.
ii) Grout injecting machine or grouting pump with inlet and outlet valves and pressure gauges. It should be capable of injecting cement grout up to 5 kg/cm2
iii) An air tight, pressure mixer chamber, with stirrer for proper mixing of the grout and keeping it in proper colloidal suspension during grouting.
iv) Flexible pressure hose pipes for transmitting grout from pressure chamber to ports embedded in the masonry.
v) Drilling equipment, pneumatic or electric, for drilling of holes upto 25mm dia.
vi) 10-20mm dia G.I. pipes with couplers, or lockable type PVC nozzles.

Driiling hole for nozel fixing

Pressure grouting

Pressure grouting tools

Pressure grouting procedure

1.     PVC grouting nozzles of 130mm length & 10mm outer dia, with a stopper at the outer end, shall be fixed on the concrete surface @ 1m C/C or at the particular location of water leakage, by drilling a hole of same dia and inserting upto a depth of 80mm. Cement paste shall be used to fix and seal the sides of the nozzle.

2.     After 24 hrs of fixing of nozzles, grouting operation shall be carried out.

3.     The Grout shall be prepared with mix of OPC & non shrink grouting chemical, W/C ratio shall be maintained not more than 0.45.

4.     Grout mix shall be prepared of good consistency for ease in passing through grouting pipe.

5.     The grouting shall be done under pressure of 3 to 5 kg/cm2 using grouting pump.

6.     Grout shall be pumped till the time it flows into the structure, filling all the gaps inside. The consumption of grout in each hole shall be recorded.

7.     Once completed and grout is completely set, the projected parts of the nozzles shall be removed, surface shall be cleaned and finished smooth.

Source: www.construction-guide.in/civil-works/plain-and-reinforced-concrete/pressure-grouting-procedure