1. Part 66/1 “Polyurethane resins in rock grouting and tunnel repairs”
(Part 66 , PP 2007, animation+p/r compr.)
Copyright notice Unauthorised copying of this presentation as whole or in parts in any form or by any means, electronic, photocopying, recording or otherwise, without prior written permision is prohibited.
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2. Family and company history in civil engineering
NAJDER engineering® is a consulting company as well as a specialist contractor within civil and foundation engineering.
We are preparing technical concepts, design projects, analyses and performing jobs as a subcontractor.
Tomasz Najder joined in the period of Skånska Cementgjuteriet (today Skanska AB) as a member of Supervising Team on the project “Second Dry Dock in Gdynia Shipyard” in Poland.
Tomasz Najder gained his experiences in Stabilator AB (daughter company in Skanska Group) as site manager, project manager and internal consultant (”trouble-shooter”), as Production Manager (Stabilator AB- International Division in Poland), in Polish-Swedish company Stabilator Sp. z o.o. (Skanska Group) as Vice President and Executive Manager – Managing Director.
Anna Elżbieta Najder (wife) owned Polish company Polibeton Sp. o.o. and now Swedish Najder engineering® since 1997 (until 2005 operating as Polimark International) – operating globally.
Anna Monika Najder (daughter) together with Tomasz Najder (as the President of the Board and Executive Manager) owned Polish Najder engineering® operating in Poland.
Family Najder is working within mining, tunneling and civil engineering since six generations.
From the beginning of 2014 company is operating under new name and organization form Najder Engineering AB (AB = Aktiebolag in Swedish → partnerships or limited in English) – with Tomasz Najder as co-owner, Managing Director and Senior Consultant. Anna Elżbieta Najder (wife) is the second co-owner.
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3. Field of activity Foundation engineering and soil investigations.
Reinforcement of existing foundations (underpinning) of industrial buildings, housing estates and ancient monuments (piling, anchors, injections).
Tunneling, rock stability and soil improvement (deep mixing method, high/low-pressure injection, lime-cement columns).
Stabilization of slopes and embankments (geogrids, soil reinforcement, drainage, geotextiles).
Sealing of existing embankments, dams, dikes and waste deposits. Flood defense.
Biological engineering, gabion constructions, coast protection.
Leakage and moisture counteraction (insulations, drainages, sealing injections, dilatation repair) in concrete and brickworks structures.
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4. Grout = liquid → solid form in the crack
Grout – An injection fluid, generally referred to as grout is a pumpable material (suspension, solution, emulsion or mortar) injected into a soil or rock formation which stiffens and sets with time and thereby changes the physical characteristics of the formation (for consolidation or/and for sealing)
1. Suspensions = particles suspended in water
Water + cement corns (alt. microcements, ultra fine cements, fly ash etc.)
Water + cement corns + fillers (ballast like sand)
liquid → solid form by hydratation
2. Solutions = chemicals diluted in water
Water + sodium/natrium silicates + reactans
Water + colloidal silica SiO2 + NaCl or CaCl2
liquid → solid form by gelling (chemical reaction)
3. Resinous grouts = pre polymers or monomers or isomers
(2 or more components in liquid and/or powder form)
Water + acrylic polimers (hydrogels)
1-comp. and 2-comp. polyurethanes
Urea-silicate resins (foams)
Phenolic foams
liquid → solid form by polymerisation (3-D linking)
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6. The groutability of fine cracks is related to the width of the crack and the grain size of the grout material, expressed as a groutability ratio for rock in the following formula (Weaver 1991):
15%
Hansen 2003
For groutability ratios greater than 5, grouting is considered consistently possible.
For groutability ratios less than 2, grouting is not considered possible.
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7. Penetration of cement grouts; D/d vs. water-cement ratio
D/d = min 6 (at too high pumping rate)
D/d D
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water-cement ratio
1.0
2.0
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OPC
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Penetration of cement grouts; D/d vs. water-cement ratio
(Axelsson, Gustafson 2007) 7

8. The ability of a grout to penetrate cavities, channels and porous material (penetrability) depends on two things: rheology and filtration tendency Extensive laboratory tests on stable, low w/c-ratio grouts show that the most significant limitation to their penetrability is the tendency of cement grains to agglomerate into an impermeable filter cake besides of flocculation due to presso-filtration.
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9. Flocculation means a gathering together or clotting of fine particles in a dispersed state to form lager agglomerations. When Portland cements and bentonite (especial in high dosage) are mixed together with water, the solid particles flocculate due to electrostatic attraction between the positive and negative charge sites on the particles.
Bleed develops as the cement particles settle due to the effects of gravity and allow free water to bleed from the suspension. If a grout has high bleed capacity, it will not fully fill the pore space within the soil or fractures in a rock due to the bleed water which forms as it sets For stable grouts, bleed should be as low as possible (preferably less than 2%), but in no case should be more than 5%.
Presso-filtration is a measure of bleed under pressure. The pressure filtration coefficient is a measure of how much water is forced out of a sample under pressure in a given period of time.
Injecting grouts into small apertures is similar to pressing the grout against a filter material. The “filtration tendency” of the grout is the property of the grout whereby a plug of grain can be formed at the crack opening or within the crack.
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10. 0.10 mm
PLUG !!!
Penetrability meter test for OPC grouts (MC, UFC) instead of bleed test!
Grout passed through different filters in penetrability meter test
Amount of passed through different used filters
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11. Ordinary Portland Cement - successful penetration = f (d/D, .........)
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12. Result of grouting = fn (---):
There are two ways to set, or harden, liquid sodium silicates for grouting applications.
The first way is by lowering the silicate’s pH. This causes the SiO2 species to polymerize into a gel. Some setting agents will hydrolyze over time and form an a
cid that will set the silicate. By controlling the composition of the setting agent, and therefore the rate of hydrolysis, the gel time of the grout can be tightly controlled. The second way to set a silicate grout is to react it with soluble metals to form insoluble metal silicates.
These grouts generally have higher strength and are lower in cost. Typically, PQ’s N® sodium silicate is used for grouting applications. It is diluted to reduce its viscosity, so that it penetrates soils more easily.
The viscosity adjustment takes into account the soil permeability and the strength requirement of the grouted mass.
The strength of a silicate-grouted soil is influenced by several factors: concentration of silicate in the grout formulation composition and particle size distribution
of the soil selection and amount of hardening agents  chemistry of the surrounding waters Soil grouting and ground modification with sodium silicate is a sophisticated engineering application and requires specialized equipment and expertise.
Result of grouting = fn (---):
Type of grout (corn dimensions, if any) vs. cracks width.
Properties of grout: cohesion (if any), viscosity and its shear strength.
Grouting pressure vs. rock and soil strength.
Pumping rate vs. grout-take of the rock and soil.
If the pumping rate ˃ the grout-take
grouting can cause rock fracturing (soil bursting) and heave
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13. Ordinary Portland Cement – partially penetration
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14. Maximum radius of penetration Higher cohesion than OPC
Radius of penetration vs. MC cohesion = factor limiting grout access into rock mass
Maximum radius of penetration
Rmax = Pmax x t / C
Higher cohesion than OPC
No cohesion
Microcement
Chemicals and resins
lower particle size
lower bleeding
higher coagulation
no bleeding
no coagulation
lower “particle size”
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15. OPC
MC, UFC
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16. Permeability limits of grouts in soil and rock
10-6
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Permeability limits of grouts in soil and rock

17. OPC
MC, UFC
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18. Lugeon water tests
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ISO/DIS

19. Rock fracturing by water. False Lugeon values !!!
Hydrojacking, i.e. the dilation (or widening) of existing paths begins in rock types of little strength at pressures smaller than 10 bar (in hard rock, in sedimental even lower).
It causes an over-proportionate increase of the water take before the reference pressure is reached.
Under such conditions the Lugeon-value referring to 10 bar pretends a larger permeability compared to the original one. This discrepancy impairs our assessment.
In rock types of great strength the dilation of existing paths begins at pressures above bar, thus the absorption rate at the reference pressure reflects still the original permeability.
Hydrofracturing splits latent discontinuities producing a fissure as soon as the testing or grouting pressure reaches “the critical pressure”, different from case to case.
It causes a much larger effect of pretence: the latent planes absorb no water during the low-pressure steps but large amounts after fracturing.
It is obvious that the wrong assessment of the original permeability has considerable consequences
Hydrojacking and hydrofracturing are particularly effective in grouting work where even higher pressures are usually applied. (?????)
Friedrich-Karl Ewert
Rock fracturing by water. False Lugeon values !!!
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20. ViscosityOPC ˃˃ Viscositywater α
Typical rheological laws for two types of fluids
pressure (bar)
shear stress
OPC Binghamian fluid
CohesionOPC ˃˃ Cohesionwater (= 0)
ViscosityOPC ˃˃ Viscositywater α
viscosity
Water = Newtonian fluid
yield stress (cohesion)
Bindham yield point
grout flow (l/min)
shear strain or shear rate
Cement suspension ≠ water !!!!!
Lugeon test is performed with Newtonian fluid
Grouting is performed with Binghamiam fluid
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21. ≤ 1.0 Amenability Lugr Ac = Luwa where: Ac = amenability coefficient
Amenability is the ability of the particular grout to penetrate joints and other defects premeated with water.
It is defined by the amenability coefficient (Ac) of the grout, which is expresssed as follows:
Lugr
Ac =
Luwa
≤ 1.0
where: Ac = amenability coefficient
Lugr = Lugeon permeability of the grout
Luwa = Lugeon permeability of water
The grout rheology is to be adjusted so as to maintain as high an amenability coefficient
as possible.
This should generally be greater than 75%, and preferably higher.
(Nauts 1995)
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22. Amenability coefficient Ac = ?
Mixing plant
water
Equipment for Lugeon water tests
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cement grout

23. The proposal of rock classification vs. groutability
Lugeon
Lugeon 1a 2a
clay fill
stable cement grouts
chemicals and resins 1b 2b
chemicals and resins
chemicals and resins
Recommended:
High grout-take
Low grout-take
cement
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chemicals
resins

24. Description 2- comp. PUR 1- comp. PUR
Chemical differences between so-called 2-component polyurethanes (“dual component” PUR) and 1-component polyurethanes (“single component” PUR)
Description
2- comp. PUR
1- comp. PUR
Base System
Resin = B
Reagents
Hardener = A
Catalysator (accelerator, aktivator) = CAT
Preparation
A + B
B + CAT
Reaction Starts
After Mixing
After Contact with Water
(min 6%)
Reaction Start Time
Almost Immediately
= f (temp.) → (20”– 30’)
Variable on Site
(“in situ”)
= f (temp., % CAT) → (1’– 6’)
Reaction Start
Set
Factory Pre-Set otherwise option with “accelerators”
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Hydrophilic grout will absorb the water it finds in the concrete or soil (rock).
Hydrophobic grout will repel it and push it away.
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25. Convenient in low temperatures
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Convenient in low temperatures
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26. “hockey stick” reaction
Polyurethanes (fast-moderate-, slow reacting)
Sodium/natrium silicates
Epoxy resins
Cement based suspensions
“hockey stick” reaction
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27. Climate Iceland - low temperature problems with cement based grouts
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28. pumping pressure + CO2 (expansion pressure) One-component PU resins
Viscosity vs. time
2’- 12’
30”- 3’ + %
x 10÷30
pumping pressure
pumping pressure CO2 (expansion pressure)
One-component PU resins
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Simple hand pump for water flushing through the packers and membrane pump for 1-comp. PU resins
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29. Injection with PUR in concrete
mechanical packer
Injection with PUR in concrete
1 mm
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30. Fracturing of concrete
α ≈ 30º
2/3 D
1/3 D
Foam 1
Alternative drilling
Foam 2
Fracturing of concrete
to high pump speed
or to big angle α
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Foam
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Principles for drilling and PUR grouting of cracks in the concrete wall

31. Mechanical packers with HP-pan-head nipple
Sealing of cracks in the concrete with polyurethanes
Mechanical packers with HP-pan-head nipple
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32. The general sequence of PUR grouting
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33. Drilling and PU (1-comp.) injection – sealing of cracks in bottom slab
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34. Sealing of construction joint with 1-comp. PU resin.
PUR foam
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Sealing of construction joint with 1-comp. PU resin.
To the right: semi-elastic final form of reacted PUR

35. Sealing of dilatation joint with 1-comp. PU resin
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Sealing of dilatation joint with 1-comp. PU resin

36. Cut & cover tunnel. Dilatation joint 2 days after PUR injection
Cut & cover tunnel. Dilatation joint after concrete pouring
Recommended sealing method with 1-comp. PU resin
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37. Sealing of cracks in concrete lining of TBM tunnel with 1- comp. PUR
Sealing of joints of concrete lining of TBM tunnel with 1- comp. PUR
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38. „The Great Melen Project“ in Istanbul (TBM):
- 2-comp. PUR injektion for sealing of cracks and dilatations
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39. Partially successful grouting with epoxy resin (to the left) and with acrylic resin (to the right) in the underground tunnels in Warszawa (mechanical packers to small !!!)
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40. Thank You for Your attention!
THE END of Part 1 of 2
Thank You for Your attention!
Ph.D Civ. Eng. Tomasz Najder
Senior Consultant
Najder Engineering AB
Movägen 3,
Saltsjöbaden - Sweden
Org. no: – 5433
Tel: 0046 (0)
Fax: 0046 (0)
Mobil: 0046 (0)
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41. Welcome to www.najder.se
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