Crimson Publishers Publish With Us Reprints e-Books Video articles

Full Text

Research & Development in Material Science

Factors Affecting Rheological Characteristics 0f Cement Suspension Grouts - A Mini Review

Christodoulou Dimitrios*

Department of Environmental Sciences, University of Thessaly, Larissa, Greece

*Corresponding author: Christodoulou Dimitrios, Assistant Professor, Department of Environmental Sciences, University of Thessaly, Campus Gaiopolis, Larissa, Greece.

Submission: March 16,2022;Published: May 31,2022

DOI: 10.31031/RDMS.2022.17.000903

ISSN: 2576-8840
Volume 17 Issue 1

Abstract

The use of very fine cement grouts for injection into fine-to-medium sands has been proposed to circumvent problems associated with the permanence and toxicity of chemical grouts and the inability of ordinary cement grouts to permeate soil formations finer than coarse sand. Τhe rheological properties of a cement suspension grout significantly determine the success of an injection especially in those cases where geometric constraints do not arise from the size relationship between soil voids and suspension solids. For this reason, it is considered necessary to determine the rheological characteristics of the suspensions during the design phase of an injection program, so as to select the optimal suspensions on a case-by-case basis. In general, determining the rheological behavior of a cement suspension is not an easy task as there are many factors that intervene in it and have opposite effects. In this paper information is given regarding the effect of these factors on the rheological behavior of cement suspensions.

Keywords:Permeation grouting; Suspensions; Microfine cements; Rheological characteristics; Consistency

Introduction

The safe construction and operation of many technical projects often requires the improvement of the properties and mechanical behavior of the soil formations. The shear behavior of a soil material is of particular interest because it has a direct impact on practical bearing capacity problems [1,2], stability of slopes and embankments [3,4] as well as permanent seismic movements of slopes [5]. The basic rheological characteristics of cement suspensions are consistency and plastic viscosity. Cohesion is considered to play an important role in grout injectability and penetrability, as the distance that a suspension can penetrate depends on it. This is because it sets the value of the injection pressure required to start the flow and determines the penetration length at which the injection pressure is balanced, at which point the flow stops. On the other hand, the viscosity controls the injection rate and the behavior of the suspension when in the flow state depends on this [6,7]. Consistency and viscosity values should be adjusted appropriately so that control is not lost, and the injection process is optimized [6]. The process of optimizing the rheological properties of cement suspensions is not particularly difficult, as there are several methods by which they can be tested. These methods provide either the addition of certain components to the composition of the suspensions or the use of an appropriate type of cement or the change of the water-to-cement (W/C) ratio. Pure cement suspensions show a viscosity ranging from 5cP to 100cP [8] and increased consistency, indicating that, in general, improvement of their rheological characteristics is required. According to Gouvenot [9], suspensions with a viscosity of not more than 5cP should be used to achieve satisfactory results in injection injections, while Kutzner [8] states that the cohesion of suspensions should not exceed 50Pa in applications. field.

Effect of superplasticizer and bentonite addition on cement suspension consistency

The most popular method of reducing the viscosity and consistency of cement suspensions is considered to be the use of superplasticizers [10-12]. In fact, the use of super fluidizers can lead to significant differences in the rheological model to which cement suspensions are subject, as it is possible for viscoplastic fluids with pseudoplastic flow behavior to be converted to Newtonian fluids [13]. The extent of the reductions achieved in viscosity and cohesion values depends on both the content and the type of super fluidizer [14-16]. Of course, the uncontrolled increase in the content of super fluidizer can lead to a change in the behavior of the suspensions and bring the opposite results from the desired. Incompatibilities have also been observed between cement types and certain superplasticizers and therefore any superplasticizer suspension compositions should be tested by preliminary laboratory tests [14].

Many times, and especially in cases where the penetration length is desired, the combined use of super fluidizers with flow regulators (eg: welan gum) is recommended, which cause an increase in consistency and viscosity [17]. In this way a balance of the action of the super fluidizers is achieved, the quality of the suspension is not altered, and cohesion and viscosity values can be obtained closer to the desired ones [18,19]. There are other chemical improvers used in cement suspension compositions, but for other reasons that indirectly affect the rheological properties of the suspensions. Typically, the use of coagulation accelerators (eg: calcium chloride, sodium silicate) is reported to cause an increase in viscosity [11,19], while the use of isopropyl alcohol (IPA) as a retardant causes a drastic reduction in viscosity [15].

The use of certain additives causes adverse effects on the rheological properties of cement suspensions. Cement-bentonite suspensions are known to behave as Bingham-type fluids [20]. The presence of bentonite has been found to cause more increase in consistency and less viscosity [21-23], while also exhibiting thixotropic behavior in cement suspensions [24]. For this reason, bentonite should be used as a rheological enhancer only in those cases where it is desired to limit the penetration of the suspensions [25]. In Italy, with the production of MISTRA suspensions, a significant reduction in the negative effects of bentonite use on the rheological behavior of suspensions has been achieved [26]. Cement suspensions containing fly ash, silica fume and natural pozzolan [27,28] exhibit similar behavior. In fact, the presence of silica fume in cement suspensions is reported to bring about thixotropic behavior characteristics in the suspensions [29].

This effect of the additives on the rheological characteristics of the cement suspensions is attributed to the fact that they are fine-grained materials with a grain size smaller than that of the cement grains. This results in an increase in the specific surface area of the solids within the suspensions leading to the capture of a larger amount of water reducing the one remaining available for the suspension to flow. This phenomenon takes on even great proportions in those cases where a cement of finer fineness than ordinary cements is used as the basis of the suspension [28,30,31], which is due to the higher reactivity of the cements. in relation to pozzolans.

Effect of blaine specific surface area and cement type on cement suspension consistency

In general, it has been observed that increasing the specific surface area of cement leads to the preparation of suspensions with significantly higher cohesion values and viscosity [11,31]. For this reason, the use of superplasticizers in the manufacture of fine-grained cements is considered imperative, while the use of bentonite should be avoided [21]. In addition, the type of cement has been shown to play an important role in the rheological characteristics of the suspensions. In particular, suspensions based on fine-grained slag cements show significantly lower viscosity and consistency values than corresponding Portland cement suspensions of comparable fineness, which is a consequence of the low activity of slag [15]. In fact, the suspensions of finegrained slag cements show lower viscosity and consistency than the suspensions of ordinary Portland cements. This difference in viscosity values is more significant at lower W/C ratios (≤1:1) and decreases considerably at higher W/C ratios [14].

Effect of W/C ratio on the cohesion of cement suspensions

The effect on the magnitude of the viscosity and consistency of the cement suspensions caused by the W/C ratio is significant. Increased W/C ratios provide larger amounts of water available for the flow of suspensions, which translates into suspensions as a reduced value of viscosity and cohesion, as documented by many research efforts [32-34]. These reductions are more pronounced at lower W/C ratios (≤2:1) and appear to be exponential. On the contrary, in high ratios (W/C ≥4: 1) the differences in viscosity due to change in the W/C ratio can be considered as negligible. This is due to the fact that at high W/C ratios the cement grains separate quite well so that the contacts between them - which could affect the viscosity - are few [14,33]. It has also been found that with increasing mixing time there is an increase in the viscosity of the suspensions [27,35]. The mixing time has a similar effect on the consistency of the suspensions, but only in cases where the W/C ratio is quite low [35].

Acknowledgment - Funding

Grateful appreciation is extended to Ioannis N. Markou, Associate Professor of Civil Engineering Department of Democritus University of Thrace (D.U.TH.) for his insightful critique of this research effort and its successful funding. The research effort reported herein is part of the research project PENED-03ED527, which was co-financed by the European Union - European Social Fund (75%) and the Greek Ministry of Development-General Secretariat for Research and Technology (25%). The contribution of TITAN Cement Company S.A. was substantial for the selection, chemical analysis, pulverization, and grain-size analysis of the cements.

References

  1. Lokkas Ph, Papadimitriou E, Alamanis N, Papageorgiou G, Christodoulou D, Chrisanidis Th (2021) Significant foundation techniques for education: A critical analysis. WSEAS Transactions on Advances in Engineering Education 18: 7-26.
  2. Lokkas Ph, Chouliaras I, Chrisanidis Th, Christodoulou D, Papadimitriou E, Paschalis E (2021) Historical background and evolution of Soil Mechanics. WSEAS Transactions on Advances in Engineering Education 18: 96-113.
  3. Alamanis N (2017) Failure of slopes and embankments under static and seismic loading. American Scientific Research Journal for Engineering, Technology and Sciences (ASRJETS) 35(1): 95-126.
  4. Alamanis N, Zografos C, Papageorgiou G, Xafoulis N, Chouliaras I (2020) Risk of retaining systems for deep excavations in urban road infrastructure with respect to work staff perception. International Journal of Scientific & Technology Research 9(2): 4168-4175.
  5. Alamanis N, Dakoulas P (2019) Simulation of random soil properties by the Local Average Subdivision method and engineering applications. Energy Systems, 12: 1-21.
  6. Chuaqui M, Bruce DA (2003) Mix design and quality control procedures for high mobility cement-based grout. Proceedings of the 3rd International Conference on Grouting and Ground Treatment. Johnsen FL, Bruce AD, Byle J, (Eds.), New Orleans, USA, ASCE, New York, USA, Geotechnical Special Publication 2: 1153-1168.
  7. Eriksson M, Friedrich M, Vorschulze C (2003) Variations in the rheology and penetrability of cement-based grouts - an experimental study. Cement and Concrete Research 34(7): 1111-1119.
  8. Kutzner C (1982) Grout mixes and grouting work. Proceedings, Symposium on Recent Developments in Ground Improvement Techniques, Bangkok, Thailand, A.A. Balkema, Rotterdam, The Netherlands and Boston, MA, USA, pp. 289-298.
  9. Gouvenot D (1996) State of the art in European grouting technologies. Proceedings, Conference on Grouting and Deep Mixing. Yonekura R, Terashi M, Shibazaki M (Eds.), Tokyo, Japan, A.A. Balkema., Rotterdam, The Netherlands, 2: 833-850.
  10. Santagata MC, Bonora G, Collepardi M (1997) Super plasticized micro cement grouts. Proceedings of the CANMET-ACI Conference on Superplasticizers and Other Admixtures in Concrete, Rome, Italy, pp. 177-195.
  11. Tolpannen P, Syrjanen P (2003) Hard rock tunnel grouting practice in Finland, Sweden, and Norway: Literature study. Technical Report, Finnish Tunnelling Association.
  12. Mollamahmutoglu M, Yilmaz Y, Kutlu I (2007) Grouting performance of microfine cement and silica fume mix into sands. Journal of ASTM International 4(4).
  13. Lau D, Crawford A (1986) Grouting for the underground containment of radioactive waste. Report Prepared for Atomic Energy of Canada Ltd, Dept. of Civil Engineering, University of Torondo, Torondo, Ontario, Canada.
  14. Perret S, Palardy D, Ballivy G (2000) Rheological behavior and setting time of microfine cement-based grouts. ACI Materials Journal 97(4): 472-478.
  15. Schwarz LG, Krizek RJ (2000) Evolving morphology of early age microfine cement grout. Proceedings of the Geo Denver 2000 Conference “Advances in Grouting and Ground Modification”, ASCE, Reston, VA, USA, Geotechnical Special Publication, pp. 181-199.
  16. Svermova L, Sonebi M, Bartos PJM (2003) Influence of mix proportions on rheology of cement grouts containing limestone powder. Cement and Concrete Composites 25(7): 737-749.
  17. Warner (2007) Good rheology assures quality work. Geotechnical Special Publication, Issue 168, Grouting for Ground Improvement: Innovative Concepts and Applications (GSP 168) Geo-Denver 2007: New Peaks in Geotechnics, Proceedings of Sessions of Geo-Denver 2007, Denver, Colorado, USA.
  18. Saric-Coric M, Khayat KH, Tagnit-Hamou A (2003) Performance characteristics of cement grouts made with various combinations of high-range water reducer and cellulose-based viscosity modifier. Cement and Concrete Research 33(12): 1999-2008.
  19. Vipulanandan C, Shenoy S (1992) Properties of cement grouts and grouted sands with additives. Proceedings, Conference on Grouting, Soil Improvement and Geosynthetics. Borden RH, Holtz RD, Juran I (Eds.), New Orleans, Louisiana, USA, ASCE, New York, USA, Geotechnical Publication 1: 500-511.
  20. Deere DU (1982) Cement-bentonite grouting for dams. Proceedings, Conference on Grouting in Geotechnical Engineering. Baker WH (Ed.), New Orleans, Louisiana, USA, ASCE, New York, USA, 1: 279-300.
  21. Bremen R (1997) The use of additives in cement grouts. International Journal of Hydropower and Dams. Bartle A, Taylor R (Eds.), 4(1): 71-76.
  22. Bruce AD, Littlejohn S, Naudts CA (1997) Grouting materials for ground treatment: A practitioner's guide. Proceedings, Conference on Grouting: Compaction, Remediation, Testing. Vipulanandan C (Ed.), Logan, Utah, USA, ASCE, New York, USA, Geotechnical Special Publication (66): 306-334.
  23. Naudts A, Landry E (2003) New on-site wet milling technology for the preparation of ultrafine cement-based grouts. Proceedings of the 3rd International Conference on Grouting and Ground Treatment. Johnsen FL, Bruce AD, Byle JM (Eds.), New Orleans, USA. ASCE, New York, USA, Geotechnical Special Publication 2(120): 1200-1207.
  24. Hakansson U, Hassler L, Stille H (1992) Rheological properties of microfine cement grouts with additives. Proceedings, Conference on Grouting, Soil Improvement and Geosynthetics. Borden RH, Holtz RD, Juran I (Eds.), New Orleans, Louisiana, USA, ASCE, New York, USA, Geotechnical Publication 1(30): 551-563.
  25. Deere DU, Lombardi G (1985) Grout slurries - Thick or thin? Proceedings, Issues in Dam Grouting. Baker WH (Ed.), Denver, Colorado, USA, ASCE, New York, USA, pp. 156-164.
  26. De Paoli B, Bosco B, Granata R, Bruce DA (1992a) Fundamental observations on cement-based grouts (1): Traditional material. Proceedings, Conference on Grouting, Soil Improvement and Geosynthetics. Borden RH, Holtz RD, Juran I (Eds.), New Orleans, Louisiana, USA, ASCE, New York, USA, Geotechnical Publication 1(30): 474-485.
  27. Schwarz LG, Krizek RJ (1992) Effects of mixing on rheological properties of microfine cement grout. Proceedings, Conference on Grouting, Soil Improvement and Geosynthetics. Borden RH, Holtz RD, Juran I (Eds.), New Orleans, Louisiana, USA, ASCE, New York, USA, Geotechnical Publication 1(30): 512-525.
  28. Perret S, Ballivy G, Khayat K, Mnif T (1997) Injectability of fine sand with cement-based grout. Proceedings, Conference on Grouting: Compaction, Remediation, Testing. Vipulanandan C (Ed.), Logan, Utah, USA, ASCE, New York, USA, Geotechnical Special Publication 66: 289-305.
  29. Domone PL, Tank SB (1986) Use of condensed silica fume in Portland cement grouts. Proceedings, Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete, 2nd International Conference Malhotra VM (Ed.), Madrid, Spain, 2: 1231-1260.
  30. Littlejohn GS (1982) Design of cement-based grouts. Proceedings, Conference on Grouting in Geotechnical Engineering. Baker WH (Ed.), New Orleans, Louisiana, USA, ASCE, New York, USA, 1: 35-48.
  31. Mollamahmutoglu M (2003) Treatment of medium to coarse grained sands by fine grained Portland cement (FGPC) as an alternative grouting material to silicate-ester grouts. Cement, Concrete and Aggregates, ASTM International 25(1): 1-6.
  32. Schwarz LG, Krizek RJ (2006) Hydrocarbon residuals and containment in microfine cement grouted sand. Journal of Materials in Civil Engineering, ASCE 18(2): 214-228.
  33. Axelsson M, Gustafson G (2007) Grouting with high water / solid-ratios - Literature and laboratory study. Technical Report No. 2007, Department of Civil and Environmental Engineering, Division of Geo Engineering Research Group of Engineering Geology, Chalmers University of Technology, Göteborg, Sweden.
  34. Schwarz LG, Chirumalla M (2007) Effect of injection pressure on permeability and strength of microfine cement grouted sand. Geotechnical Special Publication, Issue 168. Grouting for Ground Improvement: Innovative Concepts and Applications (GSP 168) Geo-Denver 2007: New Peaks in Geotechnics, Proceedings of Sessions of Geo-Denver 2007, February 21, 2007, Denver, Colorado, USA.
  35. Ziming W, Daneng H, Yaosheng X (1990) Investigation of the rheological properties and groutability of fresh cement pastes. Proceedings, Rheology of Fresh Cement and Concrete, International Conference organized by the British Society of Rheology, University of Liverpool, UK, Banfill PFG (Ed.), E & FN. Spon, London, England, pp. 207-213.

© 2022 Christodoulou Dimitrios. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially.