scispace - formally typeset

Journal ArticleDOI

Development of microfine cement grouts by pulverizing ordinary cements

01 May 2012-Cement & Concrete Composites (Elsevier)-Vol. 34, Iss: 5, pp 593-603

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.
Topics: Cement (54%), Superplasticizer (51%)
More filters

Journal ArticleDOI
Fei Sha1, Shucai Li1, Rentai Liu1, Zhaofeng Li1  +1 moreInstitutions (1)
Abstract: To ensure desirable flowability, enough penetrability and less leaching of grouting materials in geotechnical engineering, the ASTM Type I Portland cement (PC), class F fly ash (FA), bentonite (B), superplasticizer (SP) and water glass were designed to improve properties of grouting materials in different aspects. The fresh-state properties i.e. flowability, spreading ability, bleeding and setting time; mechanical properties i.e. flexural strength and compressive strength; and microstructures of the cement-based grouts were investigated. The water/solid (W/S) ratio is selected as 1.0, the amounts of FA, bentonite and SP by mass of PC were 0–40%, 0–15% and 0.7%, respectively. The volume ratios of cement-based suspensions and water glass were selected as 1:1, 2:1 and 3:1. The results show that the FA and 0.7% SP enhance the flowability and spreading ability of fresh grouts, and the bentonite can enhance the stability. The effects of various FA, B, SP and water glass contents on flexural strengths of grouts are different. The class F FA, B and 0.7% SP reduce the compressive strength of hardened grouts. The performance of cement-based grouts with 20–30% class F FA, 0–5% bentonite, 0.7% SP and volume ratios of 2:1–3:1 can satisfy the requirements of high performance, environmental friendliness and low costs in geotechnical and underground engineering.

60 citations

Journal ArticleDOI
Abstract: This paper prepared a novel double liquid grouting material (ultra-fine sulfoaluminate cement-based grouting material). Slurry A was composed of ultra-fine sulfoaluminate clinker, and slurry B was made from ultra-fine anhydrite and ultra-fine quicklime in accordance with a certain proportion. The properties and hydration process of the double liquid grouting material were studied in the process of adding quicklime from 0 wt.% to 30 wt.%, and the double liquid grouting material was studied with micro-calorimeter, thermal-thermogravimetric (DTA-TG) analysis, scanning electron microscopy and energy spectrum technique (SEM-DES), marsh cone flow time, setting time, compressive strength and expansion/shrinkage tests. The results showed that the double liquid slurry had a short setting time when quicklime was added, causing the rapid development of mechanical strength. The more the quicklime content, the longer the flow time of slurry B. The early expansion ratio increased gradually with the increase of the quicklime content. The DTA-TG and SEM-DES test results indicated that the ettringite and aluminum hydroxide are the main hydration products. And the research also found that the mechanical strength of the double liquid grouting material not only depended on the ettringite concentration, but the aluminum hydroxide content was another important influence factor.

37 citations

Journal ArticleDOI
I. N. Markou1, A. I. Droudakis1Institutions (1)
Abstract: An experimental investigation was conducted in order to evaluate the influence of distance from the injection point and of parameters pertinent to the cement, the suspension and the sand on the effectiveness of microfine cement grouts. Three different cement types, each at three different gradations having nominal maximum grain sizes of 100, 20 and 10 μm, were used. Grouting effectiveness was evaluated by injecting suspensions with water to cement (W/C) ratios of 1, 2 and 3, by weight, into five uniform sand fractions with different grain sizes and eight composite sands with different gradations, using a specially constructed apparatus. Unconfined compression and permeability tests were conducted on the resulting grouted sand specimens, after curing for 28 and 90 days. Microfine cement grouted sands obtained unconfined compression strength values of up to 14.9 MPa and permeability coefficients as low as 1.3 × 10−6 cm/s or by up to 5 orders of magnitude lower than those of clean sands. The W/C ratio and the bleed capacity of suspensions as well as the effective grain size and the permeability coefficient of sands are very important parameters, since they affect substantially the grouted sand properties and are correlated satisfactorily with them. The strength and permeability of grouted sands can increase, decrease or remain constant with distance from the injection point depending on the easiness of suspension penetration into the sands. The improvement of grouted sand properties with increasing distance from the injection point is consistent with the observed increase of the cement content of grouted sands.

36 citations

Cites background or methods from "Development of microfine cement gro..."

  • ...…indicates that microfine cement suspensions, enhanced with superplasticizer, have acceptable apparent viscosity, behave as Bingham fluids, are stable for W/C = 1, have reasonable setting times for field applications and can be injected into medium-to-fine sands (Pantazopoulos et al. 2012)....


  • ...This fixed superplasticizer dosage was determined following a laboratory evaluation of the effect of various dosages on the apparent viscosity and the rheological characteristics of the pulverized cement suspensions (Pantazopoulos et al. 2012)....


  • ...Using suspensions of the same cement, Pantazopoulos et al. (2012) observed that the unconfined compression strength of the grouted sands increases with increasing cement fineness and that the effect of cement fineness is most pronounced for the thicker cement suspensions (W/ C = 1) and is…...


  • ...setting times for field applications and can be injected into medium-to-fine sands (Pantazopoulos et al. 2012)....


Journal ArticleDOI
Abstract: This paper deals with the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer. Preliminary tests were conducted to focus on the grout best able to fill a fibrous network since the goal of this study was to develop an optimized grout able to be injected in a mat of steel fibers for concrete strengthening. The grout composition was developed based on criteria for fresh state and hardened state properties. For a CEMI 42.5R based grout different high range water reducer dosages (0%, 0.2%, 0.4%, 0.5%, 0.7%) and silica fume (SF) dosages (0%, 2%, 4%) were tested (as replacement of cement by mass). Rheological measurements were used to investigate the effect of polycarboxylates (PCEs) and SF dosage on grout properties, particularly its workability loss, as the mix was to be injected in a matrix of steel fibers for concrete jacketing. The workability behaviour was characterized by the rheological parameters yield stress and plastic viscosity (for different grout temperatures and resting times), as well as the procedures of mini slump cone and funnel flow time. Then, further development focused only on the best grout compositions. The cement substitution by 2% of SF exhibited the best overall behaviour and was considered as the most promising compared to the others compositions tested. Concerning the fresh state analysis, a significant workability loss was detected if grout temperature increased above 35 °C. Below this temperature the grout presented a self-levelling behaviour and a life time equal to 45 min. In the hardened state, silica fumes increased not only the grout’s porosity but also the grout’s compressive strength at later ages, since the pozzolanic contribution to the compressive strength does not occur until 28 d and beyond.

35 citations

Journal ArticleDOI
Shucai Li1, Fei Sha1, Rentai Liu1, Qingsong Zhang1  +1 moreInstitutions (1)
Abstract: To ensure excellent rheological behavior, penetrability and mechanical property of microfine cement (MC) grout in the field work, it is essential to obtain and control its property by laboratory tests. In this study, rheological and mechanical properties of six different MC grouts (three portland-based and three slag-blended) and two ordinary Portland cements (ASTM I and III) are measured. MC suspension was prepared at five W/C ratios (1.0, 1.2, 1.5, 2.0 and 3.0) without or with superplasticizer (SP). The properties investigated in this study were: particle size distribution, rheological properties (apparent viscosity, yield stress and plastic viscosity), fresh states (mini-slump, bleed capacity and final setting time) and mechanical properties (early strength development, compressive strength, flexural strength, elasticity modulus, shrinkage/expansion and sand-consolidation strength). The results showed that rheological behaviors and mechanical properties of MC grouts were affected obviously by the W/C ratio, cement fineness, cement type and the addition of SP, etc. All MC suspensions behaved as the Bingham fluids and were stable for W/C = 1.0, 1.2 and 1.5. The detrimental effect of finer grain size on viscosity can be negated by using SP. To ensure less leaching, sufficient fluidity and enough penetrability in sand voids or micro cracks, the W/C ratio was recommended as 1.0–2.0. The SP dosages should not be excessive to avoid instability, oversaturation or long-setting.

32 citations

More filters

01 Jan 1983-
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)

510 citations

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.

383 citations

Journal ArticleDOI
01 Sep 1986-Rheologica Acta
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.

303 citations

Journal ArticleDOI
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.

136 citations

Journal ArticleDOI
Daniel Eklund1, Håkan Stille2Institutions (2)
Abstract: Grouting as a method of strengthening and sealing rock, soil and concrete is widely used. The possibilities of sealing structures are of great importance from both an economical and environmental p ...

99 citations

No. of citations received by the Paper in previous years