Microfine Cements for Permeation Grouting Democritus University of Thrace Department of Civil Engineering GREECE

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1 I.N. Markou D. Christodoulou & A. Droudakis Microfine Cements for Permeation Grouting Democritus University of Thrace Department of Civil Engineering GREECE

2 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.

3 Microfine Cement Definitions ACI Committee 552, Geotechnical Cement Grouting, defines microfine cement as a material in which d max <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 m 2 /kg and d 95 <20 µm. The Norwegian proposal divides two groups of microcements: d 95 <30 µm, microfine cement and d 95 <15 µm, ultrafine cement (Tolpannen & Syrjanen, 2003). In U.K. practice, ultrafine cements are characterized by d max 6µm (Littlejohn, 2003).

4 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

5 Commercially Available Products Manufacturer Cement Composition Grain Size (µm) Onoda MC-500 Slag+Portland d max = 15 MC-300 Portland d max < 40 MC-100 Slag d max = 8 Ciment d Origny Spinor A12, A16 Slag d 98 = 12, 16 Micromix d max = 10 Microdur RS, RF, RU, RX d 95 = 24, 16, 9.5, 6 Dyckerhoff Finosol F, U, X d 95 = 16, 9.5, 6 Microcem A, B Portland d max = 16, 12 Nittetsu Superfine, Superfine - L d max = 10 BASF Cons. Chem. Rheocem 650, 800, 900 Portland d 95 <15, d 98 <15, d 98 <10 Cementa Ultrafin Cement 16, 12 Portland d 95 = 16, 12 Taiheyo Materials Alofix MS d 98 = 12

6 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: superplasticizers (their use is necessary for fluidity increase, according to Bremen, 1997 & Saada, 2003), dispersants, retarders, accelerators Additives: bentonite (improves stability), slag, silica fume, sodium silicate, fly ash

7 Microfine Cement Suspension Properties Thick Thin Property min max min max Apparent Viscosity, n (cp) 6 > Bleed Capacity (%) Initial Setting Time (hrs) Final Setting Time (hrs) Unconfined Compression Strength, 28 days (MPa)

8 Injection Devices (1-D) Column diameter: cm Column length: m!!!

9 Device for Spherical Injections The injection funnel represents 1/33 of a sphere and enables penetration depths of approximately 75 cm.

10 Permeation Comparison It is generally believed that microfine cements can be injected into fine sands like many chemical solutions.

11 Permeation Test Results Reference W/C (by weight) Soil Penetration Length (m) Zebowitz et al., :1 medium-fine sand 1.5 Sano et al., :1, 7.5:1, 10:1 fine sand 1.92 Fujii et al., :1 medium-fine sand 2.0 Van der Stoel, :1 silty sand 2.5 Bouchelaghem & Vulliet, :1 medium sand 0.8 Bouchelaghem & Almosni, :1 medium sand 0.82 Dano & Hicher, :1 fine sand 0.9 Mittag & Savvidis, :1 fine sand 1.0 Santagata & Santagata, :1 medium-fine sand 0.46 Dano et al., :1 two fine sands 0.9 Saada et al., :1 fine sand 1.1 Andreou et al., :1, 6.7:1, 10:1 fine sand 1.1

12 Soil Improvement Thick Thin Property Permeability Coefficient, k (cm/s) Unconfined Compression Strength, 28 days (MPa) min max min max 5.5x x Reduction of Permeability Coefficient: 1 5 orders of magnitude

13 Shear Strength Dano et al., 2004 Fontainebleau Sand * CG: Cementitious Grout Reference: Krizek et al., 1986 Seine River Sand Parameters φ (deg) c (MPa) φ (deg) c (MPa) Natural Sand Sand+CG1 * Sand+CG Sand+CG

14 Applications Reference Cement Project Ground *Objective 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 *1: permeability reduction *2: improvement of soil bearing capacity

15 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)

16 Finer by weight (%) ,0 Cements 10,0 1,0 Grain size (µm) CEM I Ordinary Κοινό 38 µm 18 µm 10 µm 0,1 Cement types: CEM I (Portland), CEM II/B-M (composite) and CEM IV/B (pozzolanic) according to EN Standard Maximum grain sizes: Ordinary, 38 µm, 18 µm and 10 µm Manufacturing process: Dry grinding process

17 Grout Viscosity & Bleeding Apparent viscosity, n (cp) CEM I, 18µm w/c: 1:1 SP dosage Time (min) 0% 0.6% 1.0% 1.4% 1.8% Bleeding rate (%) κ CEM II + 1.4% SP, 18 µm 3:1 2:1 w/c : 1: 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.

18 Grout Setting & Strength Unconfined compression strength (MPa)Κ CEM II + 1.4% SP, 8µm w/c : 1:1 2:1 3: Curing time (days) 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

19 Finer by weight (%) Sands ,00 1,00 Grain size (mm) 0,10 0,01 Six clean uniform sands (one coarse, three medium and two fine sands)

20 Laboratory Injections Aims: Injectability documentation Effectiveness determination Grouted soil design parameters (static & dynamic loading)

21 Conclusions Microfine cements are manufactured with dry grinding and microfine cement grouts can also be produced in-situ with wet milling process. Microfine cement grouts with high water / cement ratios can be successfully injected in fine sands. Grouting with microfine cements improves substantially sand permeability and strength. Microfine cements have been successfully used in various grouting projects. Research efforts on microfine cement grouting technology are in progress.

1.5 Concrete (Part I)

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