Experimental and numerical study on cement paste degradation under external sulfate attack

Xu Ma, Oguzhan Copuroglu, Erik Schlangen, N Han, F Xing

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

External sulfate attack is one of the situations that may cause gradual but severe damage in cementitious materials, which may lead to cracking, increased permeability and strength loss. In this paper, thin-walled hollow cement paste cylinders with a wall thickness of 2.5mm were made considering the slow penetration process of sulfate ions under continuous immersion condition. Three types of longitudinal restraints were applied on the hollow cement paste cylinders by means of a spring and steel bars through the specimens in order to facilitate non-, low- and high-restraint conditions. Strain gauges were glued on the steel bars so as to increase the accuracy of the measurements. During the immersion tests, specimen expansion and generated stress were monitored. Additionally, sulfur element mapping was generated by EDS (energy dispersive X-ray spectrometry). Expansion behaviours of the hollow cement paste cylinders were simulated under the aforementioned restraint conditions which were carried out based on the Delft lattice fracture model. The expansion was assumed to be realized upon formation of ettringite inside the nanopores of the cement hydration products. Local expansion stresses were computed by employing the crystallization pressure theory. A comparison between the simulation and the experimental results showed reasonable correlation and tendency for further exploration of our approach.
Original languageEnglish
Title of host publication9th International Conference on Fracture Mechanics of Concrete and Concrete Structures
Subtitle of host publicationBerkeley, California USA
EditorsV. Saouma, J. Bolander, E. Landis
Number of pages9
DOIs
Publication statusPublished - 2016
Event9th International Conference on Fracture Mechanics of Concrete and Concrete Structures - University of California, Berkeley, United States
Duration: 22 May 201625 May 2016
Conference number: 9
http://framcos.org/FraMCoS-9.php#gsc.tab=0

Conference

Conference9th International Conference on Fracture Mechanics of Concrete and Concrete Structures
Abbreviated titleFraMCoS-9
CountryUnited States
CityBerkeley
Period22/05/1625/05/16
Internet address

Keywords

  • External Sulfate Attack
  • Expansion
  • Crystallization Pressure
  • Lattice Model

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