Effect of welan gum and nanoclay on thixotropy of UHPC

Teng, Lin; Zhu, Jianhua; Khayat, Kamal H.; Liu, Jiaping

doi:10.1016/j.cemconres.2020.106238

Cited by 54 publications

(12 citation statements)

References 68 publications

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“…Based on the results of Teng et al [44] for ultra high performance concrete (UHPC), using the results without Ghanami clay, the first group of calculating parameters in Equation ( 23) could be derived through calibration from the value of NC-0 [44] as:…”

Section: The First Exothermic Peak-calibration and Validationmentioning

confidence: 99%

Mathematical Modeling of Initial Exothermic Behavior and Thixotropic Properties in Nanoclay-Enhanced Cementitious Materials

Xiao,

Chen,

Cao

et al. 2024

Materials

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In the realm of cementitious materials, integrating nanoclay shows promise in enhancing properties relevant to additive manufacturing. This paper presents a novel mathematical model that combines simple empirical dissolution/nucleation Avrami-like kinetics with a thixotropic kinetics equation. To analyze the initial exothermic peak, two sets of the calculation parameter function are built to describe the exothermic rate as a function of time, following an exponential pattern. This allows for the prediction of the changes in cumulative heat and heat rate during hydration, considering different concentrations of nanoclay. In the rheological aspect, the relationship between shear stress, shear rate, and time is modeled as a combination of exponential dependencies. This enables the prediction of the variations in shear stress with one variable while holding the other constant (either time or shear rate). By integrating these aspects, this model effectively describes both the first exothermal peak and the rheological behavior during cement hydration with the inclusion of nanoclay. Validated against experimental results, these models demonstrate good accuracy (overall below 3% error), reliability, and applicability. The findings offer valuable insights into the thermal and rheological aspects of concrete printing, enabling informed design decisions for both scientific and industrial applications.

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Section: The First Exothermic Peak-calibration and Validationmentioning

confidence: 99%

Mathematical Modeling of Initial Exothermic Behavior and Thixotropic Properties in Nanoclay-Enhanced Cementitious Materials

Xiao,

Chen,

Cao

et al. 2024

Materials

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“…Increasing attention has been paid to welan gum. Welan gum, which comprises a pentasaccharide repeating unit of β-1,3- d -glucopyranosyl, β-1, 4- d -glucopyranosyl, β-1,4- d -glucopyranosyl, and α-1,4- l -rhamnopyranosyl side-chain at the O-3 of 4-linked glucopyranosyl, is a natural, degradable, microbial polysaccharide produced by Sphingomonas. − Welan gum offers higher stability than well-known guar gum in high-temperature and saline environments. − The viscosity of welan gum is high because of the regular double helix parallel arrangement structure in its molecular chain . However, its stability may be insufficient for operations under highly saline aqueous conditions.…”

Section: Introductionmentioning

confidence: 99%

Viscosity and Structure Characterization of the 1-Bromohexadecane-Modified Welan Gum in the Saline Solution

Wang

Chen

et al. 2022

Energy Fuels

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Advanced industrial (e.g., hydraulic fracturing) and environmental demands necessitate the development of natural products with excellent properties. This study developed a new polysaccharide product by hydrophobically modifying welan gum by using 1-bromohexadecane under NaOH catalysis. This is the first study reporting the introduction of a long hydrophobic chain into welan gum to enhance its viscosity in saline solutions. Comparative analyses showed that hydrophobically modified welan gum (HWG) displayed higher solution viscosity (225.58 mPa·s) than welan gum (110.34 mPa·s) with 85,000 mg·L–1 mixed salts. Moreover, the viscosity of HWG solution (20.58 mPa·s) remained higher than that of welan gum (16.39 mPa·s) at 120 °C and 170 s–1 shear stress, with 85,000 mg·L–1 mixed salts. The scanning electron microscopy images suggested network structure formation by inferring the altered surface morphology of HWG after the modification of the original welan gum structure. The Fourier transform infrared spectroscopy analysis demonstrated that the bands of the C–H and C–O–C associated with the 1-bromohexadecane increased in HWG. The changed molecular structure was confirmed using the altered diffraction bands of X-ray diffraction spectra and the decreased decomposition rate (1.08 times lower) of HWG compared with those of welan gum obtained from thermogravimetric analysis and differential thermogravimetry analysis. The pyrene-based fluorescence analysis revealed the presence of the hydrophobic microdomains of HWG. Our study suggested HWG to be a promising candidate for fabricating highly viscous and saline fluids for hydraulic fracturing fluids and other potential applications and highlighted the vital role of macromolecular structures in determining the functional properties.

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“…HPMC has good adhesive, thickening, and water retention properties, and is mainly applied in self-leveling mortar and self-compacting concrete, with the intention of improving bleeding and aggregate segregation [26,27]. Welan gum is widely applied to prevent the bleeding and segregation of mortar or concrete, as well as at higher W/C ratios, and less additive is needed [28,29]. Guar gum improves the water retention of mortar or concrete, adapts the rheological behavior of the cementitious materials, prevents aggregate segregation and improves the workability and homogeneity of cement-based systems.…”

Section: Introductionmentioning

confidence: 99%

Evaluations of All-in-One, Polycarboxylate-Based Superplasticizer with Viscosity Modifying Agents for the Application of Normal-Strength, High-Fluidity Concrete

Kong¹,

Yang

Lee

et al. 2021

Applied Sciences

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High fluidity concrete exhibits an excellent self-compacting property. However, the application of typical high-fluidity concrete is limited in the normal strength range (18~35 MPa) due to the large amount of binder. Therefore, it is important to solve these problems by adding a viscosity modifying agent (VMA) with a superplasticizer (PCE), which helps to improve the fluidity of the concrete. In addition, the rheology and stability of the concrete with VMA can be improved by preventing bleeding and segregation issues. Current studies focused on the physical phenomena of concrete such as the fluidity, rheological properties, and compressive strength of normal-strength, high-fluidity concrete (NSHFC) with different types of a polycarboxylate-based superplasticizer (NPCE). The obtained results suggested that the combinations of all-in-one polycarboxylate-based superplasticizers (NPCE) did not cause any cohesion or sedimentation even stored for a long time. The combination of three types of VMA showed the best fluidity (initial slump flow of 595~630 mm) without any segregation and bleeding, and the compressive strength at 28 days was also found to be the highest: 34–37 MPa. From these results, the combination of PCE (2.0%) + HPMC (0.3%) + WG (0.1%) + ST (0.1%) showed an 18% higher plastic viscosity and -4.4% lower yield stress than Plain.

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Effect of welan gum and nanoclay on thixotropy of UHPC

Cited by 54 publications

References 68 publications

Mathematical Modeling of Initial Exothermic Behavior and Thixotropic Properties in Nanoclay-Enhanced Cementitious Materials

Mathematical Modeling of Initial Exothermic Behavior and Thixotropic Properties in Nanoclay-Enhanced Cementitious Materials

Viscosity and Structure Characterization of the 1-Bromohexadecane-Modified Welan Gum in the Saline Solution

Evaluations of All-in-One, Polycarboxylate-Based Superplasticizer with Viscosity Modifying Agents for the Application of Normal-Strength, High-Fluidity Concrete

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