The Pressure Injection System

The Pressure Injection System can be used for injecting cracks, cold joints, expansion

joints and for soil stabilization. The system can be used to stop gushing water, to seal minor

seepage, to regain structural integrity and to waterproof and strengthen almost any concrete or

masonry structure from the positive or negative side, below grade, above grade and under water.

The system includes epoxy injection techniques as well as polyurethane injection techniques.

The following introduction focuses on the high pressure injection in conjunction with mechanical

packers. Mechanical packers eliminate many problems of the surface ports including bond

failure at pressures above 300 psi and inaccessibility in wet, and water pressured areas. High

pressure injection through mechanical packers opens a new dimension of possibilities to solve

joint and crack related problems.

Resins and equipment for low and high pressure injection, surface port and mechanical

packer injection methods and systems are available now a day. There are some standard

procedures that can be followed on most jobs. The following is a short introduction.

It is recommended to inject at a time when the cracks or joints are at the widest aspect of

their moving cycle. The reason is that sealants perform better in compression than in tension.

This is of great importance when extreme movement is expected. In addition to the good

penetration, the material won't experience any tension, since the cracks are already at the widest

aspect of their moving cycle.

Besides crack injection it is also possible to inject polyurethane grout to the back side of a

wall into the soil thus creating a grout curtain. This procedure is necessary when well defined

cracks, joints or openings of any kind cannot be detected but moisture infiltration is evident.

Another option is injection of the void between the structure and an existing membrane that had

initially been installed to prevent water leaks, but failed. Membrane failure is a common cause of

below grade water leaks.

The Pressure Injection System has been proven to be a superior system in correcting

those failures with ease by injecting from the negative side. No digging is necessary. Voids in the

structure can be sealed, defective membranes can be fixed and even water pockets behind the

structure can be effectively filled to minimize hydrostatic pressure. The injected soil will be

compacted and stabilized thus reducing water accumulation behind the structure and shifting of

loose soil. The Pressure Injection System has been proven to be extremely versatile, reliable and

economical in resolving water related and structural problems.

WATER STOP INJECTION METHODS INFORMATION SEALING CRACKS AND JOINTS

The basic steps for the injection procedure are:

1. Clean surfaces

2. Drill injection holes

3. Insert injection packers

4. Flush crack, if necessary

5. Resin injection,

6. Cleanup

STEP 1 - CLEAN SURFACES

Cleaning of the surface helps the technician to identify the exact location and the width of the

crack to be injected. Sometimes the concrete surface is hidden under a surface of mineral

deposits left from long-term water leakage. Items that obscure the crack should be removed,

because the crack must to be seen clearly in order to layout the drilling patterns for the injection

holes.

STEP 2 - DRILLING INJECTION HOLES

In order to inject the resin into the crack, it is necessary to install injection ports, also called

mechanical packers or just packers. While it is common to use surface injection ports for some

low pressure epoxy injection in dry areas, it is recommended to use packers for polyurethane

injection and high pressure epoxy injection. Surface ports will not stick to wet surfaces and they

do not tolerate high injection pressures. Quite the opposite is true with mechanical packers. The

metal-rubber type packers are made for pressures up to 5000 psi in wet and dry structures.

Before drilling the injection holes, locate rebar and conduit, and plan the pattern to minimize

damaging the bit during drilling.

It is advisable to use a high quality rotary hammer. The diameter of the average injection hole

will be 16 mm. The angle while drilling should be approximately 45 degrees or less to the

surface and towards the crack. The depth of the drill hole intersecting the crack should be

somewhere close to the middle of structure, if possible. Holes deeper than 18" are usually not

required even if the concrete being repaired is more than 36 inches thick, as long as adequate

pumping pressure is available and material is contained during injection. Holes should always be

staggered from one side of the crack to the other. This assures a higher percentage of holes

intersecting the crack, even if the angle of the crack within the concrete is not perpendicular to

the surface. No two cracks behave just alike. In some instances a crack will fill from just a few

injection packers.

The distance of the drilled holes to each other usually varies from 150mm to 500mm according

to the width of the crack. (Rule of thumb: 300mm) The wider the crack, the further apart are the

drill holes. Experience helps in deciding how far apart to drill the injection holes.

If the concrete thickness is 150mm or less, do not attempt angle drilling, set the packers straight

into the face of the crack. This will help to minimize spalling in these concrete sections.

STEP 3 - INSERT INJECTION PACKERS

Place packers in the previously drilled hole, so that the top of the rubber sleeve is below the

concrete surface. If the packer can't be pushed into the hole, tap it in. Tighten the packer with a

wrench as tight as necessary. For critical areas such as corners and badly deteriorated surfaces,

long versions of the regular packers should be used to allow a deep insertion of the expandable

rubber sleeve.

STEP 4 - FLUSH CRACK IF NECESSARY

In some circumstances, it can be very useful to flush the crack with water to improve the

subsequent penetration of the injection resin into thicker walls. Flushing helps to detect blind

drill holes, or lost continuity of a crack. The procedure starts at the lowest packer on a vertical

crack, or at the narrowest part of a crack of a horizontal surface and proceeds from packer to

packer in sequence. During flushing, it is advisable to disconnect zerk fittings from packers that

are not connected to the pressure line and thereby creating an exit for surplus liquid. After

completion of flushing, prepare for the resin injection. Flushing is not advisable for epoxy

injection.

STEP 5 - CRACK INJECTION

When all preparation work is completed, make sure the injection pump is in good working order.

All equipment that comes in contact with the chemicals must be absolutely dry. Choose the

proper resin for the correct application. The nature of the crack/joint and the conditions at the job

site determine the choice of material. Mix resins in accordance to specifications and

recommendations. Load the resin hopper and charge the pump, hose, and gun. Open the valve on

the gun, and allow all remaining solvent to pass while watching for the resin to appear. Catch all

surplus material and solvent in a waste container. Keep the hopper covered in wet environments,

especially if it is raining or water is dripping from the ceiling in an enclosed environment.

The technician should be carefully watching three points of reference:

1. The crack /packer- for resin flowing out of the work face

2. The pressure line - for pump pulsations indicating resin flow

3. The gauge (if available) - for actual injection pressure applied

Begin the injection at the point of highest resistance to ensure good penetration and minimal loss

of chemical. This is usually the lowest point on a vertical crack and the narrowest area on a

horizontal surface. First, fill the drill hole, and then start slowly injecting the crack.

Holding the pressure line allows the operator to feel the pump pulsations. The technician may tell

from the hose vibration how well the material is flowing into the crack. If a pressure gauge is

available, the pressure should be monitored and kept in a range that is just enough to allow

sufficient flow of material. This procedure helps to minimize unforeseen events like sudden

spills of material, blown out ports or spalling of defective concrete. If the crack surface exhibits

immediate free flow of resin while working the first packer, pause for a few minutes. In most

cases the resin will react fast enough with the water and expand rapidly. The resulting resin

product will heal the crack and provide a surface seal to contain the material to follow. After

waiting for approximately three to five minutes start pumping again. If the resin continues to

flow freely out of the crack, stop pumping and apply a surface seal over the crack with rapid

setting cement Renderoc Plug. When the soaked material comes in contact with water it starts

to expand, creating a fast, permanent surface seal. Resin may still flow from pinholes in the

patch, but do not be concerned as long as the majority of the resin is contained. A small amount

of leakage is beneficial because it shows the extent of resin travel.

Extremely wide cracks should be covered with a surface seal prior to injection in order to contain

the resin until cured. Under proper pumping conditions in active leak injection, the following

signs should be observed in the order listed:

1. Water displaced from the crack by the resin

2. Water and resin mix appearing at the crack

3. Pure resin from the crack

It is helpful to disconnect the zerk fitting from the packers 'ahead' to allow free port to port

travel. Proceed pumping until the resin has travelled to the next packer, and is oozing out slowly

on the visible side of the crack. Once you are assured that the resin has reached the next injection

packer, attach the zerk fitting. Shut-off resin flow, disconnect your pressure line and proceed to

the next packer. After injecting a couple packers, return to the first packer and inject again. Some

of the packers will take more grout, filling up more of the crack and creating higher density crack

filler. Some contractors re-inject up to three times. Continue in this fashion until the crack is

completely filled.

STEP 6 - CLEAN UP

Once the injection work is completed, a good and thorough cleanup is essential, because once the

resin hardens, it is almost impossible to dissolve it. Any resin spilled must be cleaned

immediately before the resin sets. The packers can usually be removed within 24 hours and the

holes should be patched. If desired, an electric grinder can be used to remove excess cured grout

that flowed out the crack.

Specification Language for the Injection of Cracks

SCOPE OF WORK All cracks exhibiting a surface width measurement of 3mm or greater are to be injected. [OR: Those cracks designated on drawings Numbers _______ are to be injected.] [OR: Those cracks field identified with blue paint are to be injected.] Unless otherwise stated, it is the intent of the specification to include the injection of designated cracks for their full length, although some segments may be narrower than specified.

PERFORMANCE Voids in excess of 3mm shall be filled minimum depth of100mm. The exact procedures and equipment selected to obtain the specified results are the contractor’s option and the contractor’s responsibility. Following injection, all porting adapters and protruding capping material shall be removed, leaving the surface of the concrete smooth.

QUALITY ASSURANCE Prior to commencing work, the contractor shall submit to the owner written instructions from the manufacturer of the proportioning dispenser as to the procedures recommended to monitor and assure its proportioning accuracy of the unit. . These recommendations are to be diligently carried out by the contractor, and the owner shall be kept advised as to when and where, so that the owner’s representative can observe the procedures.

PAYMENT TERMS Mobilisation plus Linear Foot of Crack Treated The lump sum mobilization item shall obviate any claims for additional compensation in the event actual quantities fall short of those estimated by the owner, or anticipated by the contractor. Likewise, the owner shall make no claim upon the contractor for reduced unit pricing in the event quantities exceeds those reckoned. Cracks shall be measured for payment along the cap-seal. If cracks radiating from specified cracks must be capped or injected to assure penetration of designated footage, they shall be included for payment.

PACKERS

Commercial Injection Hand Pump

No electricity needed. This professional Hand Pump is simple, easy to use. - Lightweight

- >1500 PSI

- Single component

- Pressure gauge

- Mounted on stand, draws material from container or bucket

- Compatible with the complete line of injection grouts including epoxy resins

Electric High Pressure Injection Pump

Powerful all day injection machine for high injection pressures and volume injection.

FEATURES

Injection System

- Pressure Controled

- Pressure Preadjust Knob

- Automatic Shut-Off

- Single Component

- 3000 PSI, 210 BAR

- Piston System

- Suction Tube

- Mounted on Stand

- Reliable, Easy to Use, Easy to Clean

- Connects to a Wide Range of Packers

- Works with Many Materials

Injection Pressure The injection pressure is the nominal value of the manometric pressure at which the filling material is delivered to the filler neck (packer). The filling level and the injection pressure must be constantly monitored. Excessive pressure may cause structural defects in low quality concrete which would further widen the existing cracks. The thumb rule for injections is as follows: Maximum Pressure (Pmax) = Concrete Quality x 10 (bar) /3

For M 25 concrete this means that the injection pressure at the packer must be reduced to

25 x 10/3 =83.3 bar.

Wall thickness, crack size, and resin viscosity are considered when determining port spacing. Typically,

ports are spaced one wall thickness apart to help assure full penetration without excessive loss of resin

through the back of the wall

POSITIONIG OF DRILL HOLE (INSERT) PACKERS

The distance between packers may only be slightly

exceeded. 10-15% shorter distances does not pose any problems.

The Ideal distance also depends on the temperature related pot life and filling materials.

INJECTION PROCEDURE USING DISPOSABLE PACKERS

Step 1.-The packer is attached to the injection pies and pushed into the drilled hole.

Step 2.-The packer is expanded in the drilled hole using the tightening lever. Injection mixture is injected into cracks via the valve in the packer.

A-Double lock washer. & B-Valve

Step 3.-When the injection of the material is complete and the pump is stopped, return

pressure automatically closes the valve in the packer. The tightening lever is screwed

back and the injection pipe is screwed out of the packer and removed from the hole.

The rubber sleeve on the injection packer is held in the expanded position by a double-

lock washer.