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Journal ArticleDOI

Development of microfine cement grouts by pulverizing ordinary cements

TL;DR: In this article, three different cements (CEM I, CEM II/B-M and CEM IV/B according to EN 197-1) containing 0, 23.5% and 38% of pozzolan, respectively, were pulverized to obtain three additional gradations from each cement, with nominal maximum grain sizes of 40, 20 and 10μm.
Abstract: Three different cements (CEM I, CEM II/B-M and CEM IV/B according to EN 197-1) containing 0%, 23.5% and 38% of pozzolan, respectively, were pulverized to obtain three additional gradations from each cement, with nominal maximum grain sizes of 40, 20 and 10 μm. Cements with the two finer gradations are classified as “microfine” cements. Suspension properties, groutability and effectiveness of all cements were evaluated for water-to-cement ratios (W/C) of 1, 2 and 3 by weight. A superplasticizer was used to optimize rheological properties. The properties and performance of all suspensions tested are affected primarily by W/C ratio and cement fineness. All microfine cement suspensions have acceptable apparent viscosity, behave as Bingham fluids, are stable for W/C = 1, have reasonable setting times for field applications, have mostly predictable groutability and provide satisfactory strength to grouted sands. The finer gradations of II/B-M cement exhibited the best overall behavior and are considered as the most promising compared to similar gradations of the other two cements.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a series of consolidated undrained triaxial tests on loose sandy soil (with relative density Dr = 30%) grouted with cementitious materials (zeolite and cement) having cement replacement with zeolite content (Z) of 0, 10, 30, 50, 70% and 90%, and water to cementitious material ratios (W/CM) of 3, 5 and 7 has been conducted.
Abstract: Permeation grouting with cement agent is one of the most widely used methods in various geotechnical projects, such as increasing bearing capacity, controlling deformation, and reducing permeability of soils. Due to air pollution induced during cement production as well as its high energy consumption, the use of supplementary materials to replace in part cement can be attractive. Natural zeolite (NZ), as an environmentally friendly material, is an alternative to reduce cement consumption. In the present study, a series of consolidated undrained (CU) triaxial tests on loose sandy soil (with relative density Dr = 30%) grouted with cementitious materials (zeolite and cement) having cement replacement with zeolite content (Z) of 0%, 10%, 30%, 50%, 70% and 90%, and water to cementitious material ratios (W/CM) of 3, 5 and 7 has been conducted. The results indicated that the peak deviatoric stress (qmax) of the grouted specimens increased with Z up to 50% (Z50) and then decreased. The strength of the grouted specimens reduced with increasing W/CM of the grouts from 3 to 7. In addition, by increasing the stress applied on the grouted specimens from yield stress (qy) to the maximum stress (qmax), due to the bond breakage, the effect of cohesion (c′) on the shear strength reduced gradually, while the effect of friction angle (φ′) increased. Furthermore, in some grouted specimens, high confining pressure caused breakage of the cemented bonds and reduced their expected strength.

13 citations

Journal ArticleDOI
TL;DR: In this paper, a two-stage test program was carried out to evaluate the fresh and hardened properties of seven commercial grouts, which includes three Pre-Packaged Grout mixes (PPG), three Site-Batched Grout mix (SBG), and one standard Ordinary Portland Cement grout mix(PCG).

13 citations

Journal ArticleDOI
Rentai Liu1, Chunyu Zhang1, Haojie Liu, Yan Pei1, Li Xiuhao1, Zhenjun Wang1 
TL;DR: In this paper, a focused beam reflectance measurement (FBRM) system was used to analyse the in-situ particle state characteristics of cement slurry and the grouting depth of the slurry in sand columns was tested.

13 citations

Journal ArticleDOI
TL;DR: In this paper, a microfine-cement-based grout mixed with microfine fly ash (MFA), nano-CaCO3 (NC), and superplasticizer (SP) was designed to improve the rheological and mechanical properties of grouting materials.
Abstract: Enhancement of the fluidity and mechanical performance of grouting materials has proven to be an effective method of seepage prevention in geotechnical engineering. In this research, a microfine-cement-based grout mixed with microfine fly ash (MFA), nano-CaCO3 (NC), and superplasticizer (SP) was designed to improve the rheological and mechanical properties of grouting materials, and the particle size distribution, fluidity, spreading ability, bleed capacity, setting time, and mechanical properties were studied. A water/solid (W/S) ratio of 1.2 was selected, and the contents of MFA, NC, and SP by mass of microfine cement (MC) were 0–40%, 0–2.0%, and 1.5%, respectively. The results showed that MFA and 1.5% SP improved the fluidity and spreading ability of fresh grouts, while prolonging the setting time. The addition of NC can increase the yield stress and plastic viscosity and decrease the fluidity and spreading ability; nevertheless, it obviously enhances the stability and shortens the setting time of grouts. The addition of MFA and 1.5% SP reduced the compressive strength of hardened grouts; however, the addition of NC improved the mechanical properties.

11 citations

Journal ArticleDOI
01 Aug 2013
TL;DR: In this paper, single and multi-stage triaxial compression tests were conducted to evaluate the shear strength of microfine cements grouted sands, and it was observed that the Mohr-Coulomb failure criterion represents adequately the behaviour of the grouted sand.
Abstract: Unconsolidated–undrained (single and multi-stage) triaxial compression tests were conducted to evaluate the shear strength of microfine cement grouted sands. Microfine cements of three different types were obtained by pulverising ordinary cements produced in Greece. Multi-stage triaxial compression tests can be used dependably for determination of the shear strength parameters of cement grouted sands. It has been observed that the Mohr–Coulomb failure criterion represents adequately the behaviour of the grouted sands. Grouting with microfine cement suspensions improves the strength of sands significantly, and the improvement is primarily controlled by the water-to-cement (W/C) ratio of the suspensions. The positive effect of microfine cement grouting on the shear strength of sands is mainly the addition of cohesion, which is substantial even at a distance of 1·2 m from the injection point. Grouting with suspension, using W/C = 1 provides the sand with cohesion of about 2·6 MPa. The shear strength paramete...

11 citations

References
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Book
01 Jan 1983
TL;DR: In this article, the authors discuss the application and extension of established rheological techniques to the measurement of workability in place of ''ad hoc' empirical methods, and show that cement pastes behave according to the Bingham model at low shear rates.
Abstract: This book provides information on the workability of fresh concrete. The authors discuss the application and extension of established rheological techniques to the measurement of workability in place of `ad hoc' empirical methods. They show that cement pastes behave according to the Bingham model at low shear rates. This fact combined with the fact that shear rates involved in the handling and placing of concrete are considerably less than those in the mixing process, is the probable reason why concrete itself also conforms closely to the Bingham model. On this basis the authors, drawing on practical experience, develop a practical method of measurement and control. (TRRL)

512 citations

Book
01 Dec 1989
TL;DR: Mechanical modification hydraulic modification physical and chemical modification modification by inclusions and confinement.
Abstract: Mechanical modification hydraulic modification physical and chemical modification modification by inclusions and confinement.

390 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the different aspects of the yield stress phenomenon and tried a synthesis of knowledge and concluded that the choice of observation time or shear rate to use should be related to the characteristic time of the flow process to which the result is to be applied.
Abstract: This paper reviews the different aspects of the yield stress phenomenon and attempts a synthesis of knowledge. Yield stress can be probed using constant shear stress or shear rate. The magnitude of the result depends on the time allowed to determine whether the sample has developed continuous flow or has ceased flowing. It is closely associated with creep, stress growth and thixotropic breakdown and recovery, and the characteristic times of these transient responses play a part in yield stress measurement. In thixotropic fluids, yield stress is a function of structure and hence of time. In simple thixotropy, the yield stress derived from the equilibrium flow curve is the same as that for the fully built-up structure. But in many materials, the static yield stress obtained after prolonged rest is much higher than the dynamic yield stress from the equilibrium flow curve. This is associated with the phenomenon in which the equilibrium flow curve bends upwards as the shear rate is reduced to very low values. The paper also reviews the many methods that can be used to measure yield stress. It is pointed out that the choice of observation time or shear rate to use should be related to the characteristic time of the flow process to which the result is to be applied. Examples discussed are solids suspension capability of fluids, levelling and sagging, pipeline flow and start-up power requirement of mixers.

330 citations

Journal ArticleDOI
TL;DR: In this article, a scheme for systematizing the handling of viscometric data through use of the variables apparent fluidity φa and shearing stress F is proposed.
Abstract: A scheme is proposed for systematizing the handling of viscometric data through use of the variables apparent fluidity φa and shearing stress F. The rate of shear g(F) is obtained from the relation: g(F)/F =φa[1+Δ(F)]. Methods are presented for obtaining the correction term Δ(F) from capillary and concentric‐cylinder viscometric data. Use of the proposed scheme is illustrated.

138 citations

Journal ArticleDOI
TL;DR: The possibilities of sealing structures are of great importance from both an economical and environmental point of view as discussed by the authors, and Grouting as a method of strengthening and sealing rock, soil and concrete is widely used.

121 citations