Rheological characteristics of aerial lime-based pastes with addition of biopolymers

Rheological characteristics of aerial lime-based pastes with addition of biopolymers

Paper in proceedings (conference paper)

Viscosity enhancing admixtures are widely used to improve the properties of concrete and ready-mix mortars. This study focuses on the influence of biopolymer (sodium salt of alginic acid, carrageenan, diutan gum, gellan gum, and xanthan gum) in doses of 1, 5, and 10 ‰ on the rheological properties of aerial lime-based pastes. The measurements were carried out on the Discover HR-1 hybrid rheometer with DIN concentric cylinders geometry. On the pastes the flow properties as yield stress, fluidity index and consistency coefficient as well as the viscoelastic properties (complex modulus, loss tangent, critical and flow strain) were studied. All pastes studied expressed shear-thinning behaviour and the flow curves indicated rheopectic character of samples. The significant differences in effectivity of admixtures used were observed. Xanthan and gellan gums were found less effective than the three others in influencing the rheology of aerial lime-based paste while diutan gum was so effective, that the future research with lower doses of the admixture are recommended to better explain its impact on the rheological properties.

Viscosity enhancing admixtures are widely used to improve the properties of concrete and ready-mix mortars. This study focuses on the influence of biopolymer (sodium salt of alginic acid, carrageenan, diutan gum, gellan gum, and xanthan gum) in doses of 1, 5, and 10 ‰ on the rheological properties of aerial lime-based pastes. The measurements were carried out on the Discover HR-1 hybrid rheometer with DIN concentric cylinders geometry. On the pastes the flow properties as yield stress, fluidity index and consistency coefficient as well as the viscoelastic properties (complex modulus, loss tangent, critical and flow strain) were studied. All pastes studied expressed shear-thinning behaviour and the flow curves indicated rheopectic character of samples. The significant differences in effectivity of admixtures used were observed. Xanthan and gellan gums were found less effective than the three others in influencing the rheology of aerial lime-based paste while diutan gum was so effective, that the future research with lower doses of the admixture are recommended to better explain its impact on the rheological properties.

aerial lime-based mortar; carrageenan; diutan gum; xanthan gum; alginic acid sodium salt; yield stress; viscoelastic properties

aerial lime-based mortar; carrageenan; diutan gum; xanthan gum; alginic acid sodium salt; yield stress; viscoelastic properties

ŽIŽLAVSKÝ, T.; VYŠVAŘIL, M.; ROVNANÍKOVÁ, P.

2019

16.07.2018

IOP Publishing

Construmat 2018

1757-8981

IOP Conference Series: Materials Science and Engineering

385

1

United Kingdom of Great Britain and Northern Ireland

1

6

6

http://iopscience.iop.org/article/10.1088/1757-899X/385/1/012067

http://hdl.handle.net/11012/137127

Zizlavsky_2018_IOP_Conf._Ser.__Mater._Sci._Eng._385_012067