Detail publikace

Workability of biopolymer modified aerial lime mortars studied by traditional and rheological approaches

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

Originální název

Workability of biopolymer modified aerial lime mortars studied by traditional and rheological approaches

Anglický název

Workability of biopolymer modified aerial lime mortars studied by traditional and rheological approaches

Jazyk

en

Originální abstrakt

In the building industry mainly cellulose-based viscosity modifying admixtures are used to improve the properties of concrete and dry-mix mortars. Lately the alternative biopolymers, previously used in different industries, have been tested for applicability especially in self-compacting concrete. These admixtures vary in the polymeric structure, types of functional groups, thus also in efficiency and even slightly in working mechanisms. In this work, variations of the behaviour of aerial-lime based mortars prepared with the same workability defined by flow value were studied. Mortars with three different flow values were prepared for each mixture altering only the water:binder ratio. Apart from flow table value the plunger penetration depth was also studied as another representative of traditional and simple methods. The mortars were subjected torheological testing using hybrid rheometer. The flow characteristics and viscoelastic properties of the mortars in the initial state were monitored.The plunger penetration depth results copied the flow table values in trend but with non-linear dependency, which is more apparent within higher doses of admixtures. Most of the mortars showed rheopectic behaviour, only the most water-demanding admixtures such as diutan gum, hydroxypropyl guaran, and hydroxypropylmethyl cellulose promoted the thixotropy of the mixtures. The length of linear viscoelastic region (LVR) decreased with growing flow table value and also some of the admixtures notably shortened the LVR especially for the low flow value. For admixtures with reported stabilizing properties, the value of modulus crossover was specific for each dosage and the varying flow value.Noticeable differences in the efficiency and dosage-dependency of the admixtures were observed, mainly for water consumption and viscoelastic properties of the mortars. The diutan gum and hydroxypropyl guaran were found the most competitive to the cellulose ethers.

Anglický abstrakt

In the building industry mainly cellulose-based viscosity modifying admixtures are used to improve the properties of concrete and dry-mix mortars. Lately the alternative biopolymers, previously used in different industries, have been tested for applicability especially in self-compacting concrete. These admixtures vary in the polymeric structure, types of functional groups, thus also in efficiency and even slightly in working mechanisms. In this work, variations of the behaviour of aerial-lime based mortars prepared with the same workability defined by flow value were studied. Mortars with three different flow values were prepared for each mixture altering only the water:binder ratio. Apart from flow table value the plunger penetration depth was also studied as another representative of traditional and simple methods. The mortars were subjected torheological testing using hybrid rheometer. The flow characteristics and viscoelastic properties of the mortars in the initial state were monitored.The plunger penetration depth results copied the flow table values in trend but with non-linear dependency, which is more apparent within higher doses of admixtures. Most of the mortars showed rheopectic behaviour, only the most water-demanding admixtures such as diutan gum, hydroxypropyl guaran, and hydroxypropylmethyl cellulose promoted the thixotropy of the mixtures. The length of linear viscoelastic region (LVR) decreased with growing flow table value and also some of the admixtures notably shortened the LVR especially for the low flow value. For admixtures with reported stabilizing properties, the value of modulus crossover was specific for each dosage and the varying flow value.Noticeable differences in the efficiency and dosage-dependency of the admixtures were observed, mainly for water consumption and viscoelastic properties of the mortars. The diutan gum and hydroxypropyl guaran were found the most competitive to the cellulose ethers.

Dokumenty

BibTex


@misc{BUT167323,
  author="Tomáš {Žižlavský} and Martin {Vyšvařil} and Pavla {Rovnaníková}",
  title="Workability of biopolymer modified aerial lime mortars studied by traditional and rheological approaches",
  annote="In the building industry mainly cellulose-based viscosity modifying admixtures are used to improve the properties of concrete and dry-mix mortars. Lately the alternative biopolymers, previously used in different industries, have been tested for applicability especially in self-compacting concrete. These admixtures vary in the polymeric structure, types of functional groups, thus also in efficiency and even slightly in working mechanisms. In this work, variations of the behaviour of aerial-lime based mortars prepared with the same workability defined by flow value were studied. Mortars with  three  different  flow  values  were  prepared  for  each  mixture  altering  only  the  water:binder  ratio.  Apart  from  flow  table  value  the  plunger penetration depth was also studied as another representative of traditional and simple methods. The mortars were subjected torheological testing using hybrid rheometer. The flow characteristics and viscoelastic properties of the mortars in the initial state were monitored.The plunger penetration depth results copied the flow table values in trend but with non-linear dependency, which is more apparent within higher doses  of  admixtures.  Most  of  the  mortars  showed rheopectic  behaviour,  only  the  most  water-demanding  admixtures  such  as  diutan  gum, hydroxypropyl guaran, and hydroxypropylmethyl cellulose promoted the thixotropy of the mixtures. The length of linear viscoelastic region (LVR) decreased  with  growing  flow  table  value  and  also  some  of  the  admixtures  notably  shortened  the  LVR  especially  for  the  low  flow  value.  For admixtures with reported stabilizing properties, the value of modulus crossover was specific for each dosage and the varying flow value.Noticeable differences in the efficiency and dosage-dependency of the admixtures were observed, mainly for water consumption and viscoelastic properties of the mortars. The diutan gum and hydroxypropyl guaran were found the most competitive to the cellulose ethers.",
  booktitle="ICR 2020 18th International Congress of Rheology Book of Abstracts",
  chapter="167323",
  howpublished="online",
  year="2020",
  month="december",
  pages="150--150",
  type="abstract"
}