Diutan Gum Research Articles

Drag reduction and degradation of binary polymer solutions

Polymer-induced drag reduction has yielded great potential benefits for industrial processes after more than 70 years of research. However, the limitation of low shear stability has hindered further applications. This study investigates the rheology, drag reduction rate (DR), and degradation of binary polymer mixtures comprising a rigid polymer (diutan gum, DG) and a flexible polymer (polyethylene oxide, PEO). The solutions all exhibited shear-thinning behavior, and the mixed solution was less viscous than the pure PEO or DG solutions at the total concentration of 100 ppm. When fixing the PEO concentration at 50 ppm, the mixed solution viscosity significantly increased with the DG concentration. The drag reduction performance of the pure PEO solution, pure DG solution, and various proportions of binary polymer mixtures was analyzed using an in-house rotor device. The DRs of the solutions increased with the Reynolds number (Re), and decreased with shearing time. The binary solution significantly improved the shear stability of the solution without loss of DR compared to the pure PEO solution. The theoretical model for molecular degradation in turbulent flow excellently fitted the experimental data of relative drag reduction with time. Furthermore, the synergistic interaction parameter was calculated, and it was positive for most cases in the mixtures. Additionally, when Re was fixed, the synergistic interaction parameter, related to the composition of binary polymer mixtures, initially decreased and then increased with time.

Characterization of emulgels formulated with phycocyanin and diutan gum as a novel approach for biocompatible delivery systems

Phycocyanin (PC), a protein derived from algae, is non-toxic and biocompatible. Due to its environmental and sustainable properties, it has been studied as an alternative stabilizer for food emulsions. In this sense, the main objective of this work is to evaluate the effectiveness of PC and its use in combination with diutan gum (DG), a biological macromolecule, to prepare emulgels formulated with avocado oil. Z-potential measurements show that the optimum pH for working with PC is 2.5. Furthermore, the system exhibited a structured interface at this pH. The surface tension did not decrease further above 1.5 wt% PC. Interestingly, emulsions formulated with >1.5 wt% PC showed recoalescence immediately after preparation. Although 1.5 wt% had the smallest droplet size, this emulsion underwent creaming due to the low viscosity of the system. DG was used in combination with PC to increase viscosity and reduce creaming. As little as 0.1 wt% DG was sufficient to form an emulgel when incorporated into the previous emulsion, which exhibited pseudoplastic behaviour and viscoelastic properties with very low creaming rates. However, the use of PC in combination with DG resulted in a non-aggregated and stable emulgel with 1.5 wt% PC and 0.1 wt% DG.

Eco-Designing Cosmetic Products while Preserving the Sensorial-Application Properties: An Instrumental Approach toward Sustainable Formulations

Driven by growing environmental concerns and regulations, cosmetic companies are seeking reliable methods to promptly assess the possibility of replacing high-impact ingredients with sustainable alternatives. In this work, we exploited rheological and texture analyses to evaluate the possibility of using natural and biodegradable raw materials for reformulating three commercial oil-in-water skin care emulsions from an eco-design perspective. Synthetic texturizers, like nylon-12 and PMMA, were replaced with starch, maltodextrin, and silica, while acrylic rheological modifiers were substituted with polysaccharide associations of sclerotium gum, xanthan gum, diutan gum, and carrageenan. Plant-based emollients and a biodegradable elastomer were used as alternatives to silicone oils. The flow and viscoelastic properties of the samples were characterized using rheological tests under continuous and oscillatory flow conditions. The immersion/de-immersion texture analysis allowed us to measure the mechanical properties of firmness, adhesiveness, and stringiness. A double-blind sensory test assessed the products’ application and sensory characteristics. The results revealed that rheology and texture analysis are complementary and correlated techniques, useful for predicting cosmetics’ sensory characteristics. While perfect replication of the original formulas might not be achievable, this protocol can aid formulators in selecting new eco-friendly ingredients ensuring the products’ desired application and sensory properties without compromising consumer experience.

Application of biopolysaccharide green foam fluid to enhance CO2 sequestration in high-temperature and high-salinity saline aquifer

Saline aquifer, a geological body, is widely distributed in the world and has high CO2 sequestration potential. Due to the large differences in viscosity and density between the CO2 and brine and the micro-heterogeneity of the saline aquifer, CO2 override, and viscous fingering may occur in strata, resulting in low CO2 sequestration efficiency. Following the concept of green chemistry, this study formulated CO2 foam using biopolysaccharides and a green surfactant alkyl polyglycosides (APG), to enhance the CO2 sequestration efficiency in saline aquifers. The ability of three biopolysaccharides (diutan gum, welan gum and xanthan gum) to stabilize CO2 foam was explored. According to the foam drainage activation energy and the Ostwald ripening rate, the CO2 foam with diutan gum as the stabilizer and APG as the foaming agent exhibited the favorable performance. The mechanism of diutan gum stabilizing CO2 foam was analyzed through studies on intermolecular interactions, interfacial properties, rheology, and micromorphology studies. We then investigated the effects of foam quality and flow rate on the CO2 foam rheology in sandstone cores by analyzing the changes in CO2 saturation, the matching relationship between bubble diameters under different conditions and sandstone core pore size, and the variation in foam rheology was explained. Furthermore, the ability of CO2 foam to enhance CO2 sequestration was explored in saline aquifers using core-nuclear magnetic resonance techniques. CO2 foam largely reduces the water saturation of macropores and establishes high-seepage resistance to facilitate CO2 foam diversion to the meso- and micropores. This fully leverages the space in these pores to store CO2 and greatly improves CO2 sequestration in saline aquifers.

Evaluation of Viscosity Changes and Rheological Properties of Diutan Gum, Xanthan Gum, and Scleroglucan in Extreme Reservoirs.

The chemically synthesized polymer polyacrylamide (HPAM) has achieved excellent oil displacement in conventional reservoirs, but its oil displacement is poor in extreme reservoir environments. To develop a biopolymer oil flooding agent suitable for extreme reservoir conditions, the viscosity changes and rheological properties of three biopolymers, diutan gum, xanthan gum, and scleroglucan, were studied under extreme reservoir conditions (high salt, high temperature, strong acid, and alkali), and the effects of temperature, mineralization, pH, and other factors on their viscosities and long-term stability were analyzed and compared. The results show that the three biopolymers had the best viscosity-increasing ability at temperatures of 90 °C and below. The viscosity of the three biopolymers was 80.94 mPa·s, 11.57 mPa·s, and 59.83 mPa·s, respectively, when the concentration was 1500 mg/L and the salinity 220 g/L. At the shear rate of 250 s-1, 100 °C~140 °C, scleroglucan had the best viscosification. At 140 °C, the solution viscosity was 19.74 mPa·s, and the retention rate could reach 118.27%. The results of the long-term stability study showed that the solution viscosity of scleroglucan with a mineralization level of 220 mg/L was 89.54% viscosity retention in 40 days, and the diutan gum could be stabilized for 10 days, with the viscosity maintained at 90 mPa·s. All three biopolymers were highly acid- and alkali-resistant, with viscosity variations of less than 15% in the pH3~10 range. Rheological tests showed that the unique double-helix structure of diutan gum and the rigid triple-helix structure of scleroglucan caused them to have better viscoelastic properties than xanthan gum. Therefore, these two biopolymers, diutan gum, and scleroglucan, have the potential for extreme reservoir oil displacement applications. It is recommended to use diutan gum for oil displacement in reservoirs up to 90 °C and scleroglucan for oil displacement in reservoirs between 100 °C and 140 °C.

Influence of Various Nanomaterials on the Rheology and Hydration Kinetics of Oil Well Cement.

Nanomaterials have great potential to influence the properties of cement-based materials due to their small particle size and large specific surface area. The influences of Nano-SiO2 (NS), gamma-nano-Al2O3 (GNA), alpha-nano-Al2O3 (ANA), and nano-TiO2 (NT) on the rheology and hydration kinetics of class G cement at 30 °C were investigated in this study. The nanomaterials were added in dry powder form at dosages of 1, 2, 3, 5, and 7% by weight of cement (bwoc), and their dispersion was accomplished using polycarboxylate superplasticizer (PCE) at a dosage of 1.6% bwoc. PCE provides a uniform dispersion of nanoparticles in the cement matrix, enhancing the efficiency of nanomaterials. The w/c ratio varied between 0.718 and 0.78 to form a constant-density slurry of 1.65 g/cm3. Our test results showed that NS and GNA caused significant increases in the rheology of the cement slurry, with this effect increasing with dosage, while ANA and NT tended to reduce the rheology of the slurry. Compared to a well-suspended and well-dispersed cement slurry generated by the use of PCE and diutan gum, all nanomaterials can accelerate early hydration by reducing the induction time, with GNA having the strongest influence, while NS was the only nanomaterial that further increased the long-term hydration heat release at 7 days. The stronger effect of NS and GNA on the cement slurry properties can be attributed to their higher chemical reactivity. The dosage effect on total hydration extent was relatively strong for ANA, NT, and NS from 3% to 5% but weak for GNA in the range from 3% to 7%.

Experimental study on the foam-stabilizing advantages and foam stabilization mechanism of novel microbial polysaccharides

Microbial polysaccharides are of great interest in improving foam stability due to their excellent physicochemical properties. At present, there are few reports on the improvement of foam stability by novel microbial polysaccharides diutan gum and welan gum, so that the foam stabilization mechanism of microbial polysaccharides in terms of foam drainage, coarsening and coalescence is lacking. In this paper, the foam stabilization mechanism of three microbial polysaccharides was studied in detail from drainage, coarsening and coalescence, and the superiority of diutan gum in foam stabilization was emphasized. Rheological experiments show that the interaction force between diutan gum molecules is very strong, and 0.08 wt% diutan gum can significantly change the viscosity of the solution. The microscopic characteristics of the foam shows that the diutan foam has obvious advantages in foam quality, bubble size and its distribution. For the experimental results of foam drainage, it is found that the critical drainage time of foam is related to the thickening ability of the gum and the liquid drainage half-life of diutan foam is longest. Diutan gum molecule has rod-shaped helical structure and a complex aggregation morphology, which makes diutan gum have good temperature resistance and excellent water retention. These two properties of diutan gum significantly improve its foam stabilization ability. From the analysis of foam coarsening and coalescence, adding microbial polysaccharides can slow down coarsening rate and prevent foam from coalescence. Finally, the morphology of the liquid film at the microscopic scale is observed by SEM, and the thickness of the liquid film of different foams is measured. It is found that the liquid film structure of the foam added with diutan gum is dense and the thickness of the liquid film is the thickest. This study is of great significance to the theoretical exploration of microbial polysaccharides to improve foam performance and the construction of green foam systems.

Effect of competitive adsorption between specialty admixtures and superplasticizer on structural build-up and hardened property of mortar phase of ultra-high-performance concrete

This study aims to enhance structural build-up of ultra-high-performance concrete (UHPC) without influencing the initial flowability, which is critical in repair applications (e.g., use of UHPC in thin bonded overlays for bridge deck rehabilitation). Specialty admixtures, such as a viscosity-modifying admixture (VMA), have been used to enhance the structural build-up at rest. However, the use of specialty admixtures can increase superplasticizer (SP) demand to maintain proper flowability; the synergistic effect of these admixtures on structural build-up is not well understood as the coupled admixture content can reverse the net effect on yield stress, viscosity, and thixotropy. In this study, VMAs including welan gum (WG), diutan gum (DG), and cellulose ether (CE) were used. Styrene-butadiene rubber (SBR) and acrylic ester (AE) latex polymers (LPs) that can enhance structural build-up and bond strength were also incorporated. The competitive adsorption between these specialty admixtures and SP and its effect on structural build-up, early-age hydration, compressive and pull-off strengths, porosity and entrapped air content of UHPC mortar (i.e., without fiber) were systematically investigated. Test results indicated that the incorporation of anionic WG and DG that exhibited high competitive adsorption with SP led to a 275%–450% enhancement in structural build-up despite the 55%–135% increase of SP demand. Such increase was limited to 130% when using CE, SBR, or AE that cannot effectively adsorb onto cement particles in the presence of SP. This was because the high competitive adsorption between specialty admixtures and SP strengthened the particle flocculation and promoted the cement hydration in the first hour; the latter resulted in 20%–40% enhancement in non-reversible component of structural build-up. Furthermore, the use of LP at low and moderate dosages secured high bond strength to normal strength mortar despite 8%–33% decrease in compressive strength given the increased capillary porosity. The use of VMAs increased the entrapped air and resulting 5%–15% lower compressive strength, while the bond strength was not influenced.

Experimental study on the in-situ foam performance stabilized by microbial polysaccharide and its diverting characteristics at high temperature

Foam fluid shows good performance as diverting agent for reservoir stimulation, but complex generation procedure and high flow friction restrict its further application especially in offshore fields. To overcome these limitations, the objective of this study is to create stable in-situ foam system and investigate its potential in diverting fluid in heterogeneous reservoirs at high temperature. To prepare in-situ foam system, self-generated gas system was analyzed in terms of gas production volume and production efficiency. Foaming agents and foam stabilizers were optimized at the temperatures ranging from 70 ℃ to 90 ℃. Then in-situ foaming performance of the system combining self-generated gas reactants (sodium nitrite and ammonium chloride), the foaming agent (alpha olefin sulfonate), and the foam stabilizer (diutan gum) without blender was investigated based on foaming volume and bulk stability. Single core and parallel core flooding experiments were applied to investigate the plugging ability and diverting characteristics of in-situ foam. The results showed that the large pore volume was blocked by in-situ foam even at 150 ℃ as shown by the increase of residual resistance factor during subsequent water flooding. Parallel core flooding experiments also proved the diverting ability of in-situ foams as the diversion ratio of low-permeability core was higher than that of high-permeability core during subsequent water flooding. Moreover, the diversion performance of in-situ foam strongly depended on the permeability contrast, environment temperature, permeability of low-permeability core, and injection rate. Although diversion failed when permeability contrast was more than 10, in-situ foam also had good thermal stability and diverting ability at 150 ℃ in the permeability contrast range of 3 to 8. Such stable in-situ foam shows promising potential as diverting agent in heterogeneous formation for reservoir stimulation at high temperature.

Polymer drag reduction below and above the overlap concentration

We study the polymer drag reduction (DR) for a range of concentrations below and above the overlap concentration in a Taylor–Couette geometry. We use three kinds of polymers, two flexible (polyacrylamide and polyisobutylene) and one rigid (diutan gum). It is largely known that an increasing concentration accelerates the onset of DR, but it seems that this is true only for diluted solutions. We show that for concentrated solutions, the opposite can occur. Our data also suggest that maximum drag reduction asymptote can be overpassed when one uses solutions with concentrations above the overlap concentration. We attribute this extra DR to polymer aggregation, which is more frequent in more concentrated solutions.

Formulation and Physical Characterization of a Polysaccharidic Gel for the Vehiculation of an Insoluble Phytoextract for Mucosal Application

Maintaining insoluble plant-based ingredients in suspension and ensuring long-term physical stability is particularly challenging for formulators of green cosmetics. This study aimed to evaluate the structure and applicative properties of gel and gel-cream topical formulations suitable for delivering an insoluble phytocomplex on the vaginal mucosa and maintaining its integrity. For this purpose, we studied the compatibility of Perilla frutescens (L.) Britton phytocomplex (PFP), derived from in vitro plant cell cultures and presented as a powder finely dispersed in glycerin, with different classes of natural rheological modifiers (such as xanthan gum, sclerotium gum, succinoglycan, xyloglucan, diutan gum, hydroxypropyl guar gum derivative) in gel and gel-cream formulations, to meet the needs of the cosmetic market for naturalness and biodegradability. Through rheological and texture analyses, we studied the physico–mechanical properties of the samples, comparing the performances of the chosen polysaccharides to those of acrylic polymeric rheological modifiers, evaluating their contribution in terms of stability and applicative properties. Since a weak-gel rheological pattern proved to be the optimal one to keep the actives in suspension, the associations of tamarind seed polysaccharides with succinoglycan or scleroglucan were the most suitable for the formulation of mucoadhesive gels.

Biopolymers Produced by Sphingomonas Strains and Their Potential Applications in Petroleum Production.

The genus Sphingomonas was established by Yabuuchi et al. in 1990, and has attracted much attention in recent years due to its unique ability to degrade environmental pollutants. Some Sphingomonas species can secrete high-molecular-weight extracellular polymers called sphingans, most of which are acidic heteropolysaccharides. Typical sphingans include welan gum, gellan gum, and diutan gum. Most sphingans have a typical, conserved main chain structure, and differences of side chain groups lead to different rheological characteristics, such as shear thinning, temperature or salt resistance, and viscoelasticity. In petroleum production applications, sphingans, and their structurally modified derivatives can replace partially hydrolyzed polyacrylamide (HPAM) for enhanced oil recovery (EOR) in high-temperature and high-salt reservoirs, while also being able to replace guar gum as a fracturing fluid thickener. This paper focuses on the applications of sphingans and their derivatives in EOR.

A comparison of the rheological behavior of xanthan gum and diutan gum aqueous solutions

A comparison of the rheological behavior of xanthan gum and diutan gum aqueous solutions

Enhancing rheological properties of slow releasing energy material (SREMA) for rock fragmentation under submerged conditions

Soundless cracking demolition agents (SCDAs) are a promising technology for rock fracturing in underground mineral recovery applications. In this study, a SCDA was modified to slow releasing energy material (SREMA) by incorporating diutan gum (DG) and a polycarboxylate ether superplasticizer (PCE) to acquire greater water resistance and fluidity for use in underground mineral extraction applications under submerged conditions. Additionally, SREMA can be utilized in underwater concrete demolition applications, and urban demolition works. Results indicate that the addition of DG increases washout resistance and decreases fluidity due to free water retention caused by polymer interactions with water, while PCE compensates for the fluidity loss. Results of yield stress and plastic viscosity suggest that the competitive adsorption of DG and PCE onto SREMA particles occurs in the SREMA system. In addition, SREMA exhibits shear-thinning behaviour due to DG polymer alignment in the direction of flow at high shear rates. The addition of both DG and PCE allows SREMA to be a highly fluid yet cohesive compound while maintaining adequate expansive pressure.

Using ground blast-furnace slag grouts with biopolymer additives for improving sandy soils

The mechanical performance of microfine ground-granulated blast-furnace slag grouts for improving sandy soils was evaluated using unconfined compressive strength, drained triaxial compression and Brazilian tensile strength tests of grouted sand specimens. Two activator types, namely sodium hydroxide and rapid-hardening cement (RHC), and two biopolymer additives, namely xanthan gum (XG) and diutan gum (DG), were investigated for slag-based grouts prepared at various water–binder (w/b) ratios. The bench-scale investigation examined the cured strength properties of grouted sand specimens. It was observed that the RHC activator with modest biopolymer additive and smaller w/b ratio resulted in markedly higher strength gains. In terms of activator type, compared to sodium hydroxide, the RHC resulted in significantly better performance, mobilising increased cohesion in specimens tested in drained triaxial compression. When used together with slag grouts, XG and DG mostly showed comparable strength improvements, but DG proved more effective at lower dosage in increasing tensile strength of grouted sand.

Optimization of sonication parameters to obtain food emulsions stabilized by zein: formation of zein-diutan gum/zein-guar gum complexes.

Zein as a sole material is not suitable for technological applications since it is not flexible. A possible solution to extend the applications of zein is the formation of zein-polysaccharide complexes. As a first step, sonication parameters were optimized to obtain finer emulsions formulated with zein, rosemary essential oil as food preservative, and sunflower oil, by means of response surface methodology. After the formation of these guar- or diutan-zein complexes the rheological properties of these food emulsions were evaluated. An increase in sonication power, sonication time and cycles provoked a decrease in mean droplet size and a lack of recoalescence. The optimized emulsion was the starting point to form two different complexes: zein with diutan gum and zein with guar gum at different concentrations. Rheological properties as well as the microstructure observed by field emission scanning electron microscopy (FESEM) were analyzed. Interestingly, zein-guar gum complexes did not form a rheological gel; as a consequence, emulsions containing them seem to undergo a destabilization process with aging time. In contrast, emulsions formulated with zein-diutan gum presented a 3D network, observed by FESEM technique and proved by rheological measurements. While emulsions containing zein-guar gum complexes did not form networks to stabilize oil droplets, zein-diutan gum complexes did. This work brings to light the importance of the selection of polysaccharide used in food emulsions formulated with zein. © 2021 Society of Chemical Industry.

The influence of concentration and temperature on the rheological behavior of diutan gum aqueous solutions

A thorough rheology characterization of aqueous solutions of diutan gum, in different concentration (2000, 4300, 6000, and 8000 ppm) and temperatures (20, 40 and 60 °C), was conduct in order to determine the following rheological properties: viscosity; storage modulus; loss modulus; complex modulus and complex viscosity. Tests of flow curve, structural recovery, temperature sweep, creep and recovery, frequency sweep and stress sweep were performed. Rheological models were used to fit the experimental data. The aqueous solutions of diutan gum show pseudoplastic and viscoelastic behavior. The Power-Law and the Cross models fit very well the pseudoplastic behavior of aqueous solutions of diutan gum. The storage modulus (G′), in the case of 6000 and 8000 ppm, show larger values compared to loss modulus (G″), indicating a gel behavior for this diutan gum aqueous solutions, in the angular velocities investigated (0.1 to 10 rad/s). For the aqueous solution of diutan gum with 4300 ppm, there is a crossover of the curves of G′ and G″, being G′>G″ for angular velocities greater than 1 rad/s. The exponential model of three parameters fits very well the data of the curves G′ and Gʺ as a function of the angular velocity. The Power Law model fits very well the data of the complex viscosity as a function of the angular velocity. The aqueous solution of diutan gum shows good thermal stability. The study of rheology of aqueous solutions of diutan gum can contribute to better understanding the flow behavior of these biopolymers with many applications.

Impact of Microfluidization on the Emulsifying Properties of Zein-Based Emulsions: Influence of Diutan Gum Concentration.

Microfluidization is a preparation method that can be used to obtain emulsions with submicron droplet sizes. The first objective of this study was to evaluate the influence of homogenization pressure and cycles on droplet sizes using response surface methodology. Secondly, the influence of the diutan gum concentration incorporated in the optimized emulsion on rheological properties, microstructure, and physical stability was investigated. Taking the response surface analysis into account, the emulsion processed at 20,000 psi after four cycles seemed to show the smallest Sauter diameter values. Hence, this emulsion was the starting point to incorporate diutan gum. Interestingly, the formation of a 3D network in the emulsion, observed by FESEM, was provoked by diutan gum. The emulsion formulated with 0.4 wt.% of diutan gum presented rheological gel properties and enhanced physical stability. This work highlights the importance of selecting optimized processing variables using the microfluidization technique and extends the knowledge of using diutan gum in combination with zein.

Rheological and Thermal Stability of Cationic-Modified Diutan Gum Biopolymer

Cationic diutan gum (CDG) biopolymer has been developed by incorporating a quaternary amine group on diutan gum (DG) structure to improve the thermal and rheological properties. The modification was performed by mixing DG with different N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC) concentration to produce CDG in the presence of sodium hydroxide. The FTIR results confirmed the incorporation of cationic moieties onto the CDG chains. The surface morphology observed through FESEM showed that the smooth surface of DG was converted to a connective spherical reticular structure upon CHPTAC modification. The viscosity of CDG gelling fluid was increased after modification due to electrostatic chain interaction. Rheological properties showed that the plateau-like region was observed which signifying a stable gel response towards frequency. Thermal stability analysis using static thermal aging test showed the CDG was stable up to 170 °C suggesting this biopolymer can withstand the high-temperature requirements of the upstream petroleum industry.

Role of shear stress at rest on the viscoelastic response of fresh cement pastes

Fresh concrete is composed of aggregates and cement paste, which itself is a dense suspension that exhibits a yield stress and serves as a binder that solidifies through cement hydration. Although there is relatively little reaction during the fresh state (i.e., before setting), there is still the formation of early hydration products that will influence the paste rheology. Nonzero stress at rest widely exists in concrete practice, e.g., interruption during pumping, static formwork casting, and 3D concrete printing, but its impact on eventual viscoelastic properties is not well understood. In this study, we investigated the influence of different levels of applied shear stress at rest on fresh cement pastes and show that it dramatically alters the eventual solid performance (i.e., static yield stress and stiffness). With increasing applied shear stress at rest, the cement paste exhibited increasing static yield stress and increasingly elastic behavior, where the origin was tied to the progression of hydration. Cement pastes were compared against magnesium oxide suspensions, which served as an inert model system, and an accelerated rate of static yield stress increase over time was observed in the former but not in the latter. This highlights the role of early cement hydration on the solidification behavior of fresh cement pastes in the presence of nonzero shear stress at rest. We further support this by showing that the structural evolution of cement paste under applied stress can primarily be attributed to an enhanced elastic limit, which is associated with early hydration. The influence of two common viscosity modifying admixtures, nanoclay and diutan gum, on these properties was also examined. This work demonstrates the importance of taking the shear stress at rest into consideration for laboratory rheological experiments and industrial concrete applications, as it can substantially impact the eventual solidification behavior.