1. (Part 66 short, PP 2007, 2016.09.16 animation+p/r compr.)
Part 65/ “Polyurethane resins in rock grouting and tunnel repairs Limitations of cementitious suspensions”
(Part 66 short, 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. Holter, Hognestad, Garshol 2001
The seepage of water in hardrock occurs along channels within the discontinuities of the rock mass. Between the discontinuities the rock material is often practically impermeable The conductivity of the rock mass depends on the properties of the discontinuities.
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5. Correct grouting → Kg < K None correct grouting → Kg ≥ K (!)
Dalmalm 2004
Grouted zone around the tunnel with penetration length l and hydraulic conductivity* Kg
Correct grouting → Kg < K
None correct grouting → Kg ≥ K (!)
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6. Types of grouts
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7. 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].
liquid → solid form by gelling (chemical reaction)
3. Resinous grouts = pre polymers
(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 (linking)
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8. Cement, PUR, OMR, natrium/sodium silicate, silica sol ???
1. Groutability (conductivity) of the cracked rock mass
2. Groundwater velocity and volume of water ingress in the leaking cracks
3. Rock and groundwater temperature
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9. “hockey stick” reaction
Polyurethanes (fast-moderate-, slow reacting)
Sodium/natrium silicates
Epoxy resins
Cement based suspensions
“hockey stick” reaction
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10. ground water velocity [mm/min]λ
WilkitFoam, GeoFoam λ = 15÷30 x
CarboPur λ = 3÷5 x
wash-out effect
ground water velocity [mm/min]
15 mm/sec
De Neef Scandinavia AB 1991
Factor λ
= relation between volume of material grouted / material still remaining in the rock mass after hardening vs. ground water velocity in mm/min
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12. Cementitious suspensions and their limitations
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15. 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.
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16. Equipment (mixing plants) to prepare cementitious grouts
as stable suspensions
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17. 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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18. 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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Penetration of cement grouts; D/d vs. water/cement ratio
(Axelsson, Gustafson 2007) 18

19. ? Rapid Hardening Cement 50 m Rheocem 650 Rheocem 900 15 m 9 m
Van Gamert
BASF
Rapid Hardening
Cement
50 m
10 m = 0.01 mm
Rheocem
650
15 m
Silica fume 0.2 m
Rheocem
900
9 m
0.020 mm ?
Colloidal silica MP320
0.015 m
50 m = 0.05 mm
Water ingress ≈ 0.10 mm (100 m)
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Comparison between crack dimension and size of cement-, silica fume- and colloidal silica particles
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20. 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-filtraction.
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21. 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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22. 5 %
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23. 3.300 ? 1.000 600 13 Rapid Hardening Cement 50 m Rheocem 650 15 m 1
900
9 m
Rheocem
650
15 m
600
1.000 ?
50 m = 0.05 mm
Colloidal silica MP320
0.015 m
Silica fume 0.2 m 1 13
3.300
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water ingress ≈ 0.10 mm (100 m)
Comparison between crack dimension and size of cement-, silica fume- and colloidal silica particles

24. A. The fresh grout: Density. B. The hardenend grout:
Fundamental properties and testing of cementitious grouts
A. The fresh grout:
Density.
Bleeding.
Viscosity.
Cohesion (yield point).
Initial setting.
B. The hardenend grout:
Mechanical strength.
Resistance to chemical agents.
Permeability.
Bleeding with the 1 liter traditional
graduated cylinders 2. 1.
Initial setting with the Vicat apparatus
Equipment for fundamental grout testing:
1. Apparent viscosity by means of Marsh Funnel (Marsh Viscosity).
2. Grout density with Baroid mud type balance.
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25. α Typical rheological laws for two types of fluids
pressure (bar)
shear stress
Cement grout = Binghamian fluid
Refusal pressure but at which pumping rate ???
viscosity α
yield stress (cohesion)
Bindham yield point
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Water = Newtonian fluid
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apparent
viscosity α
viscosity
grout flow (l/min)
shear strain or shear rate
Grouting Materials and Mixes
Figure as above shows two laws of rheological behavior: a purely viscous fluid such as water
(Newtonian) and a Binghamian fluid, characterized by viscosity but also by cohesion
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26. The travel distance is always finite.
The viscosity component determines the rate at which a grout travels from the grout hole under the given pressure and for a certain thickness of an open joint.
It is cohesion, however, that determines the final distance of penetration.
The travel distance is always finite.
The cohesion of the grout, thus, has the function to limit the the extension of the grouted zone while the viscosity apparent influences the time needed to fullfill the grouting, where:
Maximum radius of penetration Rmax = Pmax x t / C
Maximum volume of injected grout Vmax = 2 π x [pmax ] 2 x t3 / C2  
The maximum total uplift force Fmax = π x [pmax ] 3 x t2 / 3 C2
where: pmax is the final applied pressure,
t is the half-thickness of the joint, and
C is the cohesion (yield point) of the cement grout Lombardi
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27. ... for what ??
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Apparent viscosity measurements by means of Marsh Funnel (Marsh Viscosity) to the left
and bleeding with the 1 liter traditional graduated cylinder to the right
Abreu J.V 27

28. 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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29. Ordinary Portland Cement - successful penetration = f (d/D, .........)
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30. 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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31. Ordinary Portland Cement – partially penetration
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32. Size of particles MC, UFC (microcements, ultrafine cements)
Factors limiting grout access into cracks
and
range of penetration from the grouting point
Remedies
Size of particles MC, UFC (microcements, ultrafine cements)
Bleeding (separation, settlement) lower w/c, additives, lower Blaine
Coagulation (clogging) additives
Rheology of grout (cohesion and viscosity) additives
Turbulent flow
Roughness of joints, adherence of grout to the crack walls
“Presso-filtration” and apperance of cement grain filters additives
To short reaction time (PU-start of foaming, gelling) proper choice of grout ? ? ? ? ?
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33. Grout Mix Additives
Performance enhancing grout additives enable stable, balanced cementitious grouts to be formulated for a wide variety of field conditions.
Stable grouts are grouts that exhibit generally less than 5% bleed in 24 hours Balanced grouts resist premature blockages due to pressure filtration and thereby achieve improved penetration at lower grouting pressures.
Common grout additives include:
Bentonite – used generally up to 2% by weight of cement to improve stability under pressure and reducing shrinkage and bleeding of the grout.  Unfortunately bentonite increases both the cohesion and viscosity of grouts.
Superplasticizer – normally a napthalene sulphonate admixture used as a dispersing agent to reduce the cohesion and viscosity of the grout. Typical addition rates are % by weight of cement. 
Fly Ash – used as a pozzolan to replace up to 25% of the cement where cheaper fly ash is available. Fly ash can also be used with cement to produce a grout better resistant to aggressive groundwater. 
Silica Fume – used up to 10% by weight of cement to produce a stronger, less permeable grout with enhanced stability and resistance to pressure filtration. 
Accelerators – normally used during cold weather grouting operations or wherever faster setting times are required. 
Sodium Silicate – a flash setting additive used under high inflow/high pressure conditions. 
Thixotropic Modifier – used in flowing water conditions to produce a cohesive, water repellent grout that resists wash-out.
For most common grouting applications it is necessary to use only bentonite and superplasticiser.
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34. For OPC → Rmax ↓, P↑ For MC → Rmax ↓, P↑ For OPC, MC → Rmax ↓
For OPC, MC → Rmax ↓, P↑
Rmax ↓ , P↑
For OPC, MC → Rmax ↑, P↓
For OPC, MC → Rmax ↓
For OPC, MC → Rmax ↑, P↓
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35. → larger reactive surface → higher flocculation tendency
Higher Blaine value [cm2/g]
→ larger reactive surface
→ higher flocculation tendency
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36. 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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37. Penetrability of different grouting materials
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38. OPC
MC, UFC
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39. Permeability limits of grouts in soil and rock
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Permeability limits of grouts in soil and rock

40. OPC
MC, UFC
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41. Lugeon water tests
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42. 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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43. 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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44. ≤ 1.0 ˃ 1.0 = fracturing !!! Amenability Lugr Ac = Luwa
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
˃ 1.0 = fracturing !!!
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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45. water cement grout Equipment for amenability test
Mixing plant
water
Equipment for Lugeon water tests
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cement grout

46. 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

47. Rock testing Grouting procedure (for grouting !!! ) ˂ 0,75 ˃ 0,75
The hydraulic conductivity
measured in terms of Lugeon units
Rock testing
The rock Q rating
Tunnels allowed leakage ? l/min/100 m
Seepage under the dam ??
(for grouting !!! )
Proposal of grouting materials
and grouting mixes (w:c = ?? )
Water temperature ?
Wash-out phenomenon ?
Rock buffering ??
Max grouting pressure allowed (fracturing and/or widening allowed ?? )
˂ 0,75
˃ 0,75
Amenability coefficient (Ac)
of the grouts proposed
resins
cement
Limited Grouting Time (Stille)
Grouted grout volume expected (Lombardi - GIN)
Flow chart for sequential grouting
with cement or resins
Grouting to refusal pressure!
(ev. adjustments)
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48. Thank You for Your attention!
THE END of Part 1
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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49. Welcome to www.najder.se
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