Publication detail

Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems

BÍLEK, V. KALINA, L. NOVOTNÝ, R. TKACZ, J. PAŘÍZEK, L.

Original Title

Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems

English Title

Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems

Type

journal article in Web of Science

Language

en

Original Abstract

Significant drying shrinkage is one of the main limitations for the wider utilization of alkali-activated slag (AAS). Few previous works revealed that it is possible to reduce AAS drying shrinkage by the use of shrinkage-reducing admixtures (SRAs). However, these studies were mainly focused on SRA based on polypropylene glycol, while as it is shown in this paper, the behavior of SRA based on 2-methyl-2,4-pentanediol can be significantly different. While 0.25% and 0.50% had only a minor effect on the AAS properties, 1.0% of this SRA reduced the drying shrinkage of waterglass-activated slag mortar by more than 80%, but it greatly reduced early strengths simultaneously. This feature was further studied by isothermal calorimetry, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Calorimetric experiments showed that 1% of SRA modified the second peak of the pre-induction period and delayed the maximum of the main hydration peak by several days, which corresponds well with observed strength development as well as with the MIP and SEM results. These observations proved the certain incompatibility of SRA with the studied AAS system, because the drying shrinkage reduction was induced by the strong retardation of hydration, resulting in a coarsening of the pore structure rather than the proper function of the SRA.

English abstract

Significant drying shrinkage is one of the main limitations for the wider utilization of alkali-activated slag (AAS). Few previous works revealed that it is possible to reduce AAS drying shrinkage by the use of shrinkage-reducing admixtures (SRAs). However, these studies were mainly focused on SRA based on polypropylene glycol, while as it is shown in this paper, the behavior of SRA based on 2-methyl-2,4-pentanediol can be significantly different. While 0.25% and 0.50% had only a minor effect on the AAS properties, 1.0% of this SRA reduced the drying shrinkage of waterglass-activated slag mortar by more than 80%, but it greatly reduced early strengths simultaneously. This feature was further studied by isothermal calorimetry, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Calorimetric experiments showed that 1% of SRA modified the second peak of the pre-induction period and delayed the maximum of the main hydration peak by several days, which corresponds well with observed strength development as well as with the MIP and SEM results. These observations proved the certain incompatibility of SRA with the studied AAS system, because the drying shrinkage reduction was induced by the strong retardation of hydration, resulting in a coarsening of the pore structure rather than the proper function of the SRA.

Keywords

alkali activated slag; shrinkage reducing admixture; shrinkage; hydration; microstructure; retardation

Released

10.06.2016

Publisher

MDPI

ISBN

1996-1944

Periodical

Materials

Year of study

9

Number

6

State

CH

Pages from

1

Pages to

12

Pages count

12

URL

Full text in the Digital Library

Documents

BibTex


@article{BUT125827,
  author="Vlastimil {Bílek} and Lukáš {Kalina} and Radoslav {Novotný} and Jakub {Tkacz} and Ladislav {Pařízek}",
  title="Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems",
  annote="Significant drying shrinkage is one of the main limitations for the wider utilization of
alkali-activated slag (AAS). Few previous works revealed that it is possible to reduce AAS drying
shrinkage by the use of shrinkage-reducing admixtures (SRAs). However, these studies were mainly
focused on SRA based on polypropylene glycol, while as it is shown in this paper, the behavior
of SRA based on 2-methyl-2,4-pentanediol can be significantly different. While 0.25% and 0.50%
had only a minor effect on the AAS properties, 1.0% of this SRA reduced the drying shrinkage
of waterglass-activated slag mortar by more than 80%, but it greatly reduced early strengths
simultaneously. This feature was further studied by isothermal calorimetry, mercury intrusion
porosimetry (MIP) and scanning electron microscopy (SEM). Calorimetric experiments showed that
1% of SRA modified the second peak of the pre-induction period and delayed the maximum of the
main hydration peak by several days, which corresponds well with observed strength development
as well as with the MIP and SEM results. These observations proved the certain incompatibility
of SRA with the studied AAS system, because the drying shrinkage reduction was induced by the
strong retardation of hydration, resulting in a coarsening of the pore structure rather than the proper
function of the SRA.",
  address="MDPI",
  chapter="125827",
  doi="10.3390/ma9060462",
  howpublished="online",
  institution="MDPI",
  number="6",
  volume="9",
  year="2016",
  month="june",
  pages="1--12",
  publisher="MDPI",
  type="journal article in Web of Science"
}