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The American Concrete Institute (ACI) sub-committee 236A, “Workability ofFresh Concrete,” immediately was faced, upon its creation in fall 1999, with how to determine appropriate methods to measure concrete workability. The material science-based approach to measure workability would be to use a concrete rheometer. There are several rheometers used...
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... This is basically because the employed geometries are not able to assess the stress field properly or provide a translation of the torque-rotational speed curve to the yield stress-shear rate curve (Josch et al., 2023;Le et al., 2013). In addition, different rheometers do not provide comparable results (Banfill et al., 2001) and the equipment is commonly developed for laboratory use, impairing field applications and involving high cost. ...
The aim of this work is to present a rheological assessment of mortars based on the automated slump test methodology. Was employed this equipment in order to monitor the transient and permanent regime of the slump test and its spread, correlating such parameters to rheological properties. Based on dimensionless slump/spread, yield stress and viscosity, were defined empirical models for obtaining rheological parameters, which provided correlations with an elevated coefficient of determination (R ² > 0.85). Through the analysis of the slump behavior of mortars, was able to define a correlation between the viscosity and the flow maximum slump velocity (R ² = 0.90), showing that the viscosity could be measured based on the slump velocity. Furthermore, with basis on a physical description of the slump test related to the Reynolds number, were defined three distinct stages in the slump process: the viscous (constituted by high viscosities), the intermediary (coexistence of viscous and inertial effects), and the inertial (characterized by low viscosities and a higher sensibility towards the lifting of the mold). Lastly, the dynamic similarity of the analyzed material (vertical and radial axes, Re z /Re r ∼1) indicates that the shear rate can be measured based on the vertical direction of the flow (slump).
... This has been made possible through a better understanding of the effect of mixture design on rheological properties [1,2], better measurement tools, a more profound grasp of fluid dynamics concepts applied on concrete materials [3], and the use of numerical simulations [4][5][6][7]. However, measuring rheological properties on cement-based materials remains a challenging task [8], and it is known from previous studies that different rheometers may deliver varying rheological values for the same mixtures [9,10]. Two major rheometer comparison campaigns were held in Nantes (France) in 2000 [9] and in Cleveland (USA) in 2003 [10]. ...
... However, measuring rheological properties on cement-based materials remains a challenging task [8], and it is known from previous studies that different rheometers may deliver varying rheological values for the same mixtures [9,10]. Two major rheometer comparison campaigns were held in Nantes (France) in 2000 [9] and in Cleveland (USA) in 2003 [10]. These campaigns showed that, in general, the rheometers could distinguish similar trends in (dynamic) yield stress and plastic viscosity; however, differences were systematically observed in absolute values. ...
... The larger the absolute value of yield stress or viscosity, the larger the scatter appears to be. In general, these results are in line with the results obtained two decades ago in the two testing campaigns on concrete rheometers [9,10]. Figure 5 shows the static yield stress values obtained according to the procedure described in Sect. ...
Recent developments in understanding the rheology of mortar and concrete as well as applying this understanding in the practice of construction necessitate an accurate assessment of materials’ rheological properties. It is well known that different rheometers for mortar and concrete deliver different results, as this was shown over 15 years ago in two measuring campaigns comparing concrete rheometers. Considering newly developed rheometers, including those to evaluate interface rheology and structural build-up at rest, as well as additional measurement procedures and data interpretation techniques, a new comparison campaign was carried out in 2018 at the Université d’Artois, in Bethune, France. This new campaign focused on measuring workability characteristics, flow curves, static yield stress values, interface properties and tribological data. A total of 14 different devices capable of measuring one or more of the above-mentioned characteristics were employed. These devices included four ICAR rheometers, the Viskomat XL, the eBT-V, the RheoCAD (two geometries), the 4SCC rheometer (two geometries), the plate test, the sliding pipe rheometer, a tribometer and an interface tool for the ICAR rheometer. This paper describes the mixture design and rationale of the five investigated concrete and three investigated mortar mixtures, design and analysis of the experiments, and comparison of test results. The findings confirmed some of the conclusions from two previous testing campaigns and expanded the findings to more modern concrete mixtures and more diversified sets of rheological devices. The investigated rheometers yielded different absolute values for material parameters, but they all were able to similarly distinguish between mixtures qualitatively. For static yield stress and interface rheology measurements, similar conclusions were obtained as for flow curves.
... The fresh state performance of the CC, CRCA, and FRCA concrete mixtures was appraised by consistency measurements (i.e., slump test) and rheological characterization using a planetary rheometer (IBB) as illustrated in Figure 3a. The H-shaped impeller ( Figure 3b) has a height of 100 mm and length of 130 mm and covers an area of 4002.3 mm 2 whereas the bowl's diameter is 360 mm, and its height is 250 mm [47]. The targeted slump is 100 ± 20 mm which falls within the range of 40 mm to 300 mm thus, deeming this device suitable to evaluate the concrete mixtures [48]. ...
... The targeted slump is 100 ± 20 mm which falls within the range of 40 mm to 300 mm thus, deeming this device suitable to evaluate the concrete mixtures [48]. Despite the output of the IBB rheometer providing only two Bingham parameters (i.e., yield stress in N.m and plastic viscosity in N.m.s) which are not presented in fundamental units (Pa and Pa.s, respectively), similar trends can be found when analyzing rheological profile on other types of rheometers [47,48]. The flow curves for the mixtures appraised in this study were therefore plotted using the output dataset from the IBB rheometer. ...
The ever-growing urgency to combat climate change has led the civil construction industry to develop and adopt sustainable construction materials and methods. The so-called recycled concrete aggregate (RCA) emerges as an alternative to decrease the carbon footprint of new concrete construction, the disposal of waste concrete, and the use of non-renewable natural resources such as cement and aggregates. RCA can be produced from crushing waste concrete; yet challenges remain when using RCA in concrete especially its fresh state behaviour due to its distinct multi-phase nature and microstructure (i.e., presence of residual mortar (RM)/residual cement paste (RCP)). In this context, this work presents a comprehensive study of the rheological behaviour of recycled concrete mixtures through the use of a planetary rheometer (IBB). The recycled mixtures were proportioned using the Equivalent Volume (EV) method, a mixture proportioning technique that accounts for the RM and RCP, respectively, and improves the recycled mixture's hardened state properties, incorporating distinct: 1) coarse RCA having various inner qualities (i.e., 25 MPa, 35 MPa and 45 MPa) and mineralogy (i.e., limestone and granite) and 2) fine RCA made from natural or manufactured sand while having different degrees of processing (i.e., crushed once vs continuously crushed). All recycled mixtures produced in this study present shear-thinning profiles, suggesting that these mixtures are suitable for applications under high torque regimes such as vibrated or pumped concrete. Additionally, they were produced with 100% recycled concrete aggregate (either fine or coarse RCA), classifying them as low embodied energy mixtures.
... Various mortar and concrete rheometers have State of the art been designed and produced in the last few decades. Many of these rheometers are explained and presented in [26,27,28] within a framework of international and national round-robin tests. A detailed discussion on the application of such devices is beyond the scope of this thesis, however, the following literature is recommended in the specified topics. ...
... • Characterizing rheological properties of particle suspensions [29] • Comparing different rheometers and resulted rheological parameters [26,27] • Avoiding inaccurate interpretations of rheological measurements [30] • Reiner-Riwlin transformation equations for Bingham [29], modified Bingham [31] and Herschel-Bulkly models [32] • Considering plug flow in wide-gap concentric cylinder [31,33] Among all available rheological models, the Bingham model is the simplest non-Newtonian model that can describe the rheological properties of a fluid using two parameters: yield stress and plastic viscosity (see Section 2.1.1). For the derivation of pipe flow equations for concrete, the Bingham model was used by various researchers. ...
... The application of this method is well-known in the field of cement and concrete rheology. Interested readers can refer to [26,27,29,30]. The Reiner-Riwlin equation was also extended for Herschel-Bulkley [32] and modified Bingham [31] models to include non-linearity. ...
The correlation between concrete rheological parameters and its pumping behavior under consideration of the so-called lubricating layer has been investigated for decades. In this thesis, flow-induced particle migration (FIPM) was studied in-depth, as the main underlying mechanism for the formation of the lubricating layer. Conventionally vibrated and self-compacting concretes were chosen as the target mixtures. Furthermore, cementitious model concretes, containing colored glass beads, were proposed to obtain further insights into the FIPM and its impact on pumping. The mixtures were differentiating with regard to particle volume fractions, mortars composition, maximum particle size and particle size distributions. In the experiments, various established methods were used to characterize the rheological properties and the pumping behavior of the concretes. New methodologies for estimating the thickness of the lubricating layer and the particle distribution in pumped cross-sections were proposed as well. The rheological properties and pumping behavior of real and model concretes were in agreement with the state-of-the-art literature. Based on the radial particle distributions, it was illustrated that the particle migration intensifies by increasing the particle size and decreasing the total volume fraction of solid particles. Furthermore, in highly-concentrated poly-dispersed model concretes, the particle concentration curves consist of a sudden jump close to the pipe wall and a relatively uniform distribution in the inner zone of the pipe. In these cases, the influence of FIPM on overall flow behavior cannot be neglected. Moreover, it was shown that the lubricating layer thickness is not constant for all concrete mixtures. For poly-dispersed suspensions, the shear-induced particle migration (SIPM) has a stronger impact than the wall for forming the lubricating layer. Finally, it was concluded that a solid-liquid threshold of 1 to 2 mm is a reliable choice when investigating concrete pipe flow. The faster the concrete is pumped or the lower the yield stress of the constitutive mortar is, the smaller is the solid-liquid threshold. Based on the experimental findings, a first-order physical correlation between pumping parameters (pressure and discharge rate), particle properties (volume fraction and packing properties) and lubricating layer properties (thickness and viscosity) was proposed. Accordingly, for a simple flow topology with a shearing lubricating layer and an extruding yield stress concrete, the lubricating layer thickness was computed from the competition between shear-induced fluxes of particles. In agreement with the driving equations of SIPM, it was assumed that the first flux correlates with the internal stress gradient in the plug concrete whereas the counteracting particle flux correlates with the shear rate in the lubricating layer. The model was validated for two flow types, pipe flow in the Sliper and Couette flow in a co-axial tribometer. The proposed model can capture the observed main features and their evolutions despite the absence of any fitting parameters.
... Betonun işlenebilirliği için ayrıca plastik viskozite gereklidir [19]. Yapılan çalışmalarda; viskozitenin çökme deneyi ile ilişkili olmadığı, çökme ile kayma eşiği değerleri ilişkisinin iyi olduğu belirtilmiştir [20][21][22]. Fiber katkının, 350 dozlu betonda kayma eşiğini azaltmasına karşılık, plastik viskozite değerinin agrega tipine göre farklılık gösterdiğini, 400 dozlu betonda ise, agrega tipinden bağımsız olarak kayma eşiği ve plastik viskozite değerini arttırdığını, basınç dayanımının kontrol betonuna göre arttığı belirtilmiştir [3]. ...
Bu deneysel çalışmada, polipropilen lif katkılı kendiliğinden yerleşen betonların (KYB) taze ve sertleşmiş haldeki özelikleri incelenmiştir. Karışımlarda dört (4) farklı tipteki polipropilen lifler iki (2) farklı oranda kendiliğinden yerleşen beton karışımı içerisinde kullanılmıştır. Taze beton deneylerinden; Yayılma, V hunisi, L kutusu, U kutusu ve J Ring deneyleri yapılmıştır. Yapılan ön çalışmalarda, polipropilen liflerin kendiliğinden yerleşen betonların işlenebilirliğini olumsuz etkilediği görülmüştür. Lif oranın belli bir oranı aştığında taze betonun kendiliğinden yerleşme özelliğini kaybettiği görülmüştür. Bu durumda taze betondaki akışkanlaştırıcı katkı ihtiyacı artmıştır. Ayrıca taze betonun, BT2 taze beton reometresi ile plastik viskozite ve kayma eşiği değerleri incelenmiştir. Karışıma eklenen liflerin taze betonun kayma eşiği değerini arttırdığı görülmüştür. Sertleşmiş beton deneylerinden basınç dayanımı ve 4 nokta eğilme dayanımı deneyleri yapılmıştır. Lif katkısının betonun basınç dayanımını olumsuz etkilemiş, buna karşın eğilme dayanımı arttırmıştır.
... The theoretical basis and the rules involving rheological measurements with the application of rotational rheometers are generally discussed in [3,43,44]. Since measurement constants were not determined for these rheometers, the results are presented using rheological constants in equivalent units -g [52] found that different rheometers gave very different values of yield stress and plastic viscosity for the same concrete, even if the measurement with these instruments gave the values directly in fundamental units. Altogether it proves that when using different rheometers, it is possible to describe rheology of fresh concrete well enough, regardless of whether it was in physical units or equivalent to physical ones. ...
Highlights mortars can be used in the SCC design and for the optimal selection of materials mortars can be used for control influence of technological factors on the SCC rheology gs determines rheological parameters important for the shear strength at rest AT determines the rheological parameters relevant to formwork pressure AT and gs depends on w/c ratio, the type of HRWR and cement Abstract Determining the relationship between the rheological parameters of the model mortar and the rheological parameters of SCC (Self-Compacting Concrete) was the aim of the work. The static yield stress and the thixotropy coefficient AT were determined, which are important due to the development of the shear strength at rest and the formwork pressure generated during SCC casting. Shear strength of SCC reflected as static yield stress gs at rest develops mainly due to a self-compaction ability of SCC. And in the longer term, gs develops due to the progressive hydration of the cement and the disappearance of the HRWR impact (loss of fluidity). The static yield stress gs depends on w/c ratio, the type of HRWR (High Range Water Reducers) and cement. SCCs with a higher w/c ratio develop static yield stress gs faster, but up to 40 min the influence of w/c ratio decreases. The stiffening of SCC due to thixotropy increases the shear strength of SCC, but at the same time, it slows down the self-compaction of concrete. Thixotropy coefficient AT depends primarily on w/c ratio, and with the same w/c, on the type of cement and HRWR. The thixotropy coefficient AT increases in the initial period of SCC being at rest. The SCC with higher w/c ratio are characterized by higher thixotropy coefficient AT but at the same time by lower static yield stress gs. The significance of the thixotropic effect for shear strength disappears in time.
... Due to the rheology of concrete, the shape and size of the building are appropriate, and the concrete mixture can be passed through the formwork to reach the required size. A good concrete flow can better complete the formwork without honeycombs and pores [23]. In recent days, the pumping of concrete needs excellent workability and flowability. ...
... e flow of matter and the deformation of particles are called rheology, which deals with the relationship between stress, strain, strain rate, and time [21,23]. e rheology of concrete has played a vital role in recent decades and has increased with the advent of self-compacting concrete (SCC) and RMC concrete. ...
... (i) BML viscometer [23,31] (ii) BTRHEOM parallel-plate rheometer [23,32,33] (iii) CEMAGREF-IMG coaxial rheometer [34] (iv) IBB rheometer [23] (v) Two-point workability apparatus [35] For this research, a two-point workability apparatus is used, and an updated version of the rheometer is developed by Tattersall and Bloomer [35]. It is developed for concrete with a slump value higher than 100. ...
To find the energy required during the mixing process of self-compacting concrete in a ready-mixed concrete plant and correlate the results with the yield stress of concrete. Power consumption required during the mixing of concrete is measured with a wattmeter connected to the mixing unit’s power supply. A coaxial cylinder viscometer is used to measure the yield stress of concrete. The clamp meter measures the power when the impeller rotates inside the coaxial cylinder viscometer, which is filled with concrete. When the impeller rotates in a coaxial cylinder filled with concrete, the power is measured by a clamp meter. Torque is obtained through the power relationship, which is an essential factor in determining the yield stress. The cost of a rheometer is so high that all construction industries, research institutions, and researchers cannot measure rheological parameters. Nowadays, all rheometers are automated; hence, the cost is very high. Tattersall’s approach of power requirement in mixing the concrete and calculating the yield stress reduces the complexity in determining the rheological parameter.
... The mass relationship of coarse aggregate to fine aggregate and to the cement matrix should be the following percentage: 50:20:30 [30]. De Larrard [8,9,15,34] developed a scientific method of designing the composition of the concrete mix that he published together with Sedran [15,34] in 1994, and in Poland, he discussed it during the "Dni Betonu" ("Concrete Days") Conference in 2004 [9]. A method worth mentioning is that of Petersson et al. [24,53], in which the amount of paste is selected using its rheological properties. ...
... The mass relationship of coarse aggregate to fine aggregate and to the cement matrix should be the following percentage: 50:20:30 [30]. De Larrard [8,9,15,34] developed a scientific method of designing the composition of the concrete mix that he published together with Sedran [15,34] in 1994, and in Poland, he discussed it during the "Dni Betonu" ("Concrete Days") Conference in 2004 [9]. A method worth mentioning is that of Petersson et al. [24,53], in which the amount of paste is selected using its rheological properties. ...
... Grube and Rickert [54] indicated that the share of paste they recommended should be 40%, whereas the share of sand should be 25% and the share of coarse aggregate 35%. It seems that despite taking into consideration various kinds of mineral additives including silica fumes, the method of Serdan and de Larrard [8,9,15,34] is used relatively rarely. The method by Okamura and Ozawa [1][2][3] is still most popular. ...
The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.
... Several rheometers have been developed to quantify the rheological behaviour of cementitious materials, including their thixotropic behaviour as a major characteristic. Beaupré et al. (2003) compared the results taken from different rheometers and measuring techniques and found a constant correlation between all results, but the absolute values differed significantly (Beaupré et al., 2003;Ferraris et al., 2001). For example, rotational rheometers (Qian and Kawashima, 2016) and plate rheometers (Mahmoodzadeh and Chidiac, 2013;Vance et al., 2015) are mostly used to test the thixotropy of cement pastes and quantify structural build-up, but they are not perfectly adapted for mortars or concrete, and this can be clearly found in the literature where most studies are conducted on mixes that do not contain aggregates. ...
... Several rheometers have been developed to quantify the rheological behaviour of cementitious materials, including their thixotropic behaviour as a major characteristic. Beaupré et al. (2003) compared the results taken from different rheometers and measuring techniques and found a constant correlation between all results, but the absolute values differed significantly (Beaupré et al., 2003;Ferraris et al., 2001). For example, rotational rheometers (Qian and Kawashima, 2016) and plate rheometers (Mahmoodzadeh and Chidiac, 2013;Vance et al., 2015) are mostly used to test the thixotropy of cement pastes and quantify structural build-up, but they are not perfectly adapted for mortars or concrete, and this can be clearly found in the literature where most studies are conducted on mixes that do not contain aggregates. ...
Digital fabrication of concrete elements requires a better understanding of the rheological behaviour of the cementitious material used. Fresh concrete is known to be a thixotropic material having time-dependent characteristics. Moreover, fresh mortars used in three-dimensional (3D) printing should maintain a sufficient shear stress to avoid any deformation or failure during printing. This paper concentrates on the experimental investigation of the buildability properties of different printable materials, on the basis of shear stress, measured using the Fall cone test. The effect of different constituents such as high-range water reducer, viscosity-modifying agent, limestone filler and water content on the evolution of the yield stress in mortars, derived from the shear stress, are studied experimentally and discussed in detail. Accordingly, the change of variables induces a quasi-linear relationship with the growth of the structuration rate and structural build-up (Athix) of mortars, which corresponds to the variation of the yield stress with time. These findings enable the use of the Athix concept and the proposed curves for designing new printable mixes that better suit the buildability properties of large-scale 3D printed structures. Notation Athix structuration rate (Pa/s) F force generated by the mass of cone (N) g gravity constant (m/s 2) H layer's height (m) h penetration depth of the cone (mm) L contour length (m) t time at rest (s) V maximum printing velocity (m/s) w/b water/binder ratio w/c water/cement ratio θ angle of the cone ρ density of the mix (kg/m 3) τ yield stress (Pa)
... Usually, the measurements of the yield stress are carried using either rotational, or plate rheometers [14]. Though, despite their attractiveness, most rheomters are not adapted for materials containing aggregates such as mortar [15]. ...
Digital construction of concrete elements using 3D printing technology has been undergoing an exponential growth in terms of research activities and demonstration projects. Though, most researches focused on the behavior of the cementitious materials used in 3D printing, without deeply immersing in the reinforcement of printed elements. In this paper, a detailed experimental program is presented to characterize the quality of the bond developed between concrete and steel bars through a series of pull-out tests. These tests are performed over printed and non-printed samples as well. When printed, the layers orientation, whether parallel or perpendicular to the steel bar is taken into consideration. Hence, it was found that a highly thixotropic material did not undermine the developed bond between printed concrete and rebar. In addition, vibrated concrete (non-printed) gave better resistance to pull-out stresses succeeded by the parallel then the perpendicular samples. Yet, the overall performance of 3D printed concrete in terms of the bond generated with steel could be rated as satisfactory.
