Stability of Air Content in Fresh Concretes with PCE-Based Superplasticizers

Open access

Abstract

Air contents of concrete are necessary for concrete durability in freeze-thaw exposure. According to the Finnish concrete code, the target value for air content varies between 4% and 5.5% for XF - exposure classes. Lately in Finland, some cases showed an elevation of air contents up to 15% in fresh air-entrained concrete at construction site and in drilled concrete samples.

The objectives of this study were to investigate the stability of air entrainment by measuring the air content elevation 30 minutes and 60 minutes after concrete mixing and investigating the concrete sensitivity to segregation. Composition of concretes used in this study include 7 different combination of PCE based superplasticizer and air-entraining agent admixtures, cement content of 425 kg/m3, two consistency classes S3 with water to cement ration of 0.33 and F5 with water to cement ration of 0.38. One cement type was used for all concrete mixes. The concretes were mixed for 2 minutes and 5 minutes mixing times.

The results show that the elevation of the air content of fresh concrete depends on the consistency of the concrete and on the used combination of superplasticizer and air-entraining agents. The higher consistency classes concretes have more risk of air elevation with some combinations of PCE-based superplasticizers and air-entraining agents. The results also indicate that short mixing time would not be enough to achieve total effectivity of some air-entraining agents, especially for higher consistency classes concrete.

If the inline PDF is not rendering correctly, you can download the PDF file here.

  • 1. Mölsä S: “The reason for the Kemijärvi railroad bridge's construction defects”. 2016. (In Finnish). [Online] https://www.rakennuslehti.fi/2016/11/kemijarven-sillan-valuvian-syyt-selvisivat-turkua-tutkitaan/ [Accessed on 29.1.2019]

  • 2. Turunsanomat News: “The background of the concrete strength problems is the elevated air content in-site”. 2016. (In Finnish). [Online] https://www.ts.fi/uutiset/paikalliset/3117381/Betonin+lujuusongelmien+taustalla+liialliset+ilmamaarat+Tyksin+tyomaalla [Accessed on 29.1.2019]

  • 3. Yang Q: “Stability of air bubbles in fresh concrete”. Master of Science Thesis. Department of Civil and Environmental Engineering Division of Building Technology. Chalmers University of Technology Göteborg Sweden 2012.

  • 4. Zakka A Carrasquillo R & Ramon L: “Effects of high-range water reducers on the properties of fresh and hardened concrete”. Research Report No. 1117-3F. Guidelines for Proper Use of Superplasticizers and the Effect of Retempering Practices on Performance and Durability of Concrete. Texas State Department of Highways and Public Transportation In Cooperation with the U.S. Department of Transportation Federal Highway Administration USA October 1989.

  • 5. Lazniewska-Piekarczyk B: ”The effect of superplasticizers and anti-foaming agents on the air entrainment and properties of the mix of self-compacting concrete”. Article in Cement Wapno Beton. May 2009 [Online] https://www.researchgate.net/publication/287164082 [Accessed on 29.1.2019]

  • 6. Łaźniewska-Piekarczyk B Szwabowski J & Miera P: ”Superplasticizer compatibility problem with innovative air-entraining multicomponent Portland cement”. Proceedings 14th International Congress on the Chemistry of Cement (ICCC 2015) Beijing China Oct. 13-16 2015. [Online] https://www.researchgate.net/publication/290392716 [Accessed on 3.10.2018]

  • 7. Kubens S: “Interaction of cement and admixtures and its influence on rheological properties”. Cuvillier Verlag Inhaberin Annette Jentzsch-Cuvillier Nonnenstieg 8 37075 Göttingen Germany 2010. [Online] https://cuvillier.de/de/shop/publications/752 [Accessed on 29.1.2019]

  • 8. Rath S & Ouchi M:. “Effective Mixing Method for Stability of Air Content in Fresh Mortar of Self-Compacting Concrete in Terms of Air Diameter”. Internet Journal for Society for Social Management Systems Issue 10 Vol. 1. 2015 sms15-6550.

  • 9. Eickschen E & Müller C: ”Interactions of air-entraining agents and plasticizers in concrete”. Concrete Technology Reports 2010 – 2012. VDZ gGmbH (Hrsg.). Düsseldorf Germany 2012. [Online] https://www.vdz-online.de/en/publications/concrete-technology-reports/ [Accessed on 29.1.2019]

  • 10. Al-Neshawy F & Punkki J: “Securing the stable protective pore system of concrete - Report for ‘Robust Air’”. Research Project Aalto University publication series Science + Technology No. 10 2017 Aalto University Helsinki Finland. Online at: https://aaltodoc.aalto.fi/handle/123456789/28893

  • 11. Finnish Transport Agency: “P-rate method for frost-resistant concrete in Finnish bridges”. (In Finnish). Report 22/2016 Helsinki Finland 2016. [Online] https://julkaisut.liikennevirasto.fi/pdf8/lo_2016-22_siltabetonien_plukumenettely_web.pdf [Accessed on 4.10.2018]

  • 12. SFS-EN 12350-7:2009 “Testing fresh concrete. Part 7: Air content. Pressure methods”. Finnish Association of Construction Product Industries SFS Helsinki Finland 2009.

  • 13. ASTM C138 / C138M-17a “Standard Test Method for Density (Unit Weight) Yield and Air Content (Gravimetric) of Concrete”. ASTM International West Conshohocken PA USA 2017 www.astm.org

  • 14. SFS-EN 12350-2:2009 “Testing fresh concrete. Part 2: Slump-test”. Finnish Association of Construction Product Industries SFS Helsinki Finland 2009.

  • 15. SFS-EN 12350-5:2009 “Testing fresh concrete. Part 5: Flow table test”. Finnish Association of Construction Product Industries SFS Helsinki Finland 2009.

Search
Journal information
Metrics
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 82 82 15
PDF Downloads 113 113 30