Microfine Cements for Permeation Grouting

Microfine Cements for Permeation Grouting

I.N. Markou
D. Christodoulou & A. Droudakis
Microfine Cements for
Permeation Grouting
Democritus University of Thrace
Department of Civil Engineering
GREECE
Need for Microfine Cements
• Suspension grouts, prepared conventionally with
ordinary Portland cement, can be successfully
injected into gravels and coarse sands.
• Chemical grouts can permeate fine sands and
coarse silts, but they are expensive and pose
environmental and health problems.
• As an alternative to chemical grouting of fine and
medium grained sands, the use of grouts prepared
with microfine cements has been proposed.
• The first microfine cement available commercially
was MC-500, manufactured by Onoda Cement
Corporation in Japan.
Microfine Cement Definitions
• ACI Committee 552, Geotechnical Cement Grouting,
defines microfine cement as a material in which
dmax<15 µm (Perret et al., 2000).
• According to the European Standard for grouting
(SFS-EN
12715),
microfine
cements
are
characterized by a specific surface area >800 m2/kg
and d95<20 µm.
• The Norwegian proposal divides two groups of
microcements: d95<30 µm, microfine cement and
d95<15 µm, ultrafine cement (Tolpannen & Syrjanen,
2003).
• In U.K. practice, ultrafine cements are characterized
by dmax≤ 6µm (Littlejohn, 2003).
Manufacturing Processes
• Dry grinding process
Fine grinding of an ordinary cement
• Wet milling process
On-site production of microfine cement-based
slurries with a special process, which allows
the elimination of the larger particles of
cement (Legendre et al., 1987, De Paoli et
al., 1992, Ahrens, 1997, Naudts & Landry,
2003).
▪ Available Products: Cemill, Microsol
Commercially Available Products
Manufacturer
Cement
Composition
Grain Size (µm)
Onoda
MC-500
Slag+Portland
dmax = 15
MC-300
Portland
dmax < 40
MC-100
Slag
dmax = 8
Spinor A12, A16
Slag
d98 = 12, 16
Ciment d’ Origny
Dyckerhoff
Micromix
dmax = 10
Microdur RS, RF, RU, RX
d95 = 24, 16, 9.5, 6
Finosol F, U, X
d95 = 16, 9.5, 6
Microcem A, B
Nittetsu
Portland
dmax = 16, 12
dmax = 10
Superfine, Superfine - L
BASF Cons. Chem. Rheocem 650, 800, 900
Portland
d95<15, d98<15, d98<10
Cementa
Portland
d95 = 16, 12
Taiheyo Materials
Ultrafin Cement 16, 12
Alofix MS
d98 = 12
Composition of Suspensions
• Water to Cement (W/C) Ratio (by weight):
▪ Thick suspensions (W/C → 0,7:1 - <2:1)
▪ Thin suspensions
(W/C → 2:1 – 12:1 in research)
(W/C → 2:1 – 4:1 in applications)
• Admixtures:
Admixtures superplasticizers (their use is
necessary for fluidity increase, according to
Bremen, 1997 & Saada, 2003), dispersants,
retarders, accelerators
• Additives:
Additives bentonite (improves stability),
slag, silica fume, sodium silicate, fly ash
Microfine Cement Suspension
Properties
Thick
Thin
min
max
min
max
Apparent Viscosity, n (cP)
6
>100
2
69
Bleed Capacity (%)
0
20
2.5
80
Initial Setting Time (hrs)
1
26
4
45
Final Setting Time (hrs)
20
26
42
88
Unconfined Compression
Strength, 28 days (MPa)
14
38
1
21
Property
Injection
Devices
(1-D)
Column diameter:
2.2 – 51 cm
Column length:
0.3 – 18 m !!!
Device for Spherical Injections
The injection funnel represents 1/33 of a sphere and
enables penetration depths of approximately 75 cm.
Permeation Comparison
It is generally believed that microfine cements can be
injected into fine sands like many chemical solutions.
Permeation Test Results
Reference
Zebowitz et al., 1989
Sano et al., 1996
Fujii et al., 1996
Van der Stoel, 1999
Bouchelaghem & Vulliet,
2001
Bouchelaghem & Almosni,
2003
Dano & Hicher, 2003
Mittag & Savvidis, 2003
Santagata & Santagata,
2003
Dano et al., 2004
Saada et al., 2005
Andreou et al., 2006
Penetration
Length (m)
2:1
medium-fine sand
1.5
5:1, 7.5:1, 10:1
fine sand
1.92
10:1
medium-fine sand
2.0
4:1
silty sand
2.5
W/C (by weight)
Soil
4:1
medium sand
0.8
4:1
medium sand
0.82
6:1
5:1
fine sand
fine sand
0.9
1.0
2.75:1
medium-fine sand
0.46
6:1
5:1
5:1, 6.7:1, 10:1
two fine sands
fine sand
fine sand
0.9
1.1
1.1
Soil Improvement
Thick
min
max
Permeability Coefficient,
5.5x10-8 9.2x10-8
k (cm/s)
10-7
10-2
Unconfined Compression
Strength, 28 days (MPa)
0.5
13.2
Property
min
4.4
max
Thin
16.2
• Reduction of Permeability Coefficient:
1 – 5 orders of magnitude
Shear Strength
Dano et al.,
2004
Parameters
Fontainebleau
Sand
Seine River Sand
φ’ (deg) c’ (MPa) φ’ (deg) c’ (MPa)
Natural Sand
39
0.0
40
0.0
Sand+CG1*
42
0.2
42
0.18
Sand+CG2
43
0.3
43
0.25
Sand+CG3
44
0.5
44
0.35
*CG:
Cementitious Grout
Reference: Krizek et al., 1986
Applications
Reference
Cement
Project
Shimoda & Ohmori, 1982
MC–500
Railway tunnel
Gravel
1, 2
Clarke, 1984
MC–500
Tunnel
Granite
1
Dasika, 1985
MC–500
Building
Sand
2
Winter et al., 1986
MC–500
Building
Fine sand
2
Legendre et al., 1987
Microsol
Oilwell
Fine sand
1
Brand et al., 1988
MC–500
Tunnel
Sand
1, 2
Weaver et al., 1992
MC–500
Waste burial
Dolomite
1
Ballivy et al., 1997
Spinor A12
Masonry
Gneiss
2
Palardy et. al, 2003
Spinor A12 Ventilation Tower Rock mass
*1: permeability reduction
*2: improvement of soil bearing capacity
Ground *Objective
1
Research Project
• Title: Development and documentation of new grouting
materials from Greek ultrafine cements for in-situ soil
improvement – reinforcement in construction
• Financing: European Union & Greek Ministry of Development
• Participants:
1. Democritus University of Thrace, Dept. of Civil Engineering
(I. Markou, Assistant Professor, D. Christodoulou & A.
Droudakis, Research Assistants)
2. University of Patras, Department of Civil Engineering
(D. Atmatzidis, Professor, & I. Pantazopoulos, Research
Assistant)
3. TITAN Cement Company
(D. Papageorgiou & Ch. Teas, Dr. Chemical Engineers)
Cements
100
CEM I
Κοινό
Ordinary
38 µm
18 µm
10 µm
Finer by weight (%)
80
60
40
20
0
100,0
10,0
1,0
Grain size (µm)
0,1
• Cement types:
CEM I (Portland),
CEM II/B-M
(composite) and
CEM IV/B
(pozzolanic)
according to EN
197-1 Standard
• Maximum grain
sizes: Ordinary,
38 µm, 18 µm
and 10 µm
• Manufacturing
process: Dry
grinding process
Grout Viscosity & Bleeding
60
CEM II + 1.4% SP, 18 µm
SP dosage
CEM I, 18µm
w/c: 1:1
0%
3:1
0.6%
100
1.0%
1.4%
1.8%
Bleeding rate (%) κ
Apparent viscosity, n (cP)
1000
40
2:1
20
10
0
50
100
150
200
Time (min)
w/c : 1:1
0
0
60
120
180
240
Time (min)
Grouts with w/c=1:1 are stable (bleed capacity <5% in
2 hours) & grouts with w/c=2:1 and 3:1 are unstable.
300
Grout Setting & Strength
10
Unconfined compression strength (MPa)Κ
CEM II + 1.4% SP, 8µm
w/c : 1:1
8
6
4
2:1
2
3:1
0
0
5
10
15
20
Curing time (days)
25
30
• Initial setting times:
4 – 8 hours
• Final setting times:
7 – 22 hours
• Pocket penetrometer
tests: grout strength
is equal to 450 kPa
after 4 – 29 hours
• Unconfined compr.
strength: 1 – 11 MPa
after 28 days of
curing
Sands
100
5-10
10-14
14-25
25-50
50-100
100-200
Finer by weight (%)
80
60
40
20
0
10,00
1,00
0,10
0,01
Grain size (mm)
• Six clean uniform sands (one coarse, three medium
and two fine sands)
Laboratory Injections
Aims:
• Injectability documentation
• Effectiveness determination
• Grouted soil design parameters
(static & dynamic loading)
Conclusions
¾Microfine cements are manufactured with dry
grinding and microfine cement grouts can also
be produced in-situ with wet milling process.
¾Microfine cement grouts with high water / cement
ratios can be successfully injected in fine sands.
¾Grouting with microfine cements improves
substantially sand permeability and strength.
¾Microfine cements have been successfully used
in various grouting projects.
¾Research efforts on microfine cement grouting
technology are in progress.