International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2533

Full Length Research Paper

Potential reduction of concrete deterioration through controlled DEF in hydrated concrete

Samo Lubej1 and Milan Radosavljevic2
1Faculty of Civil Engineering, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia. 2School of Construction Management and Engineering, University of Reading, Whiteknights, P. O. Box 219, Reading, RG6 & AW, United Kingdom.
Email: [email protected]

  •  Accepted: 21 June 2013
  •  Published: 30 June 2013

Abstract

Delayed ettringite formation (DEF) is a chemical reaction with proven damaging effects on hydrated concrete. Ettringite crystals can cause cracks and their widening due to pressure on cracked walls caused by the positive volume difference in the reaction. Concrete may show improvements in strength at early ages but further growth of cracks causes widening and spreading through the concrete structure. In this study, finely dispersed crystallization nuclei achieved by adding air-entraining agent (AEA) and short vibration of specimens is presented as the main prerequisite for reducing DEF-induced deterioration of hydrated concrete. The study presents the method and mechanism for obtaining the required nucleation. Controlling long-term DEF by providing AEA-induced crystallisation nuclei, prevented excessive and rapid initial strength improvements, and resulted in a slight increase of compressive strength of fine grained concrete with only marginally lower density.

 

Key words: Delayed ettringite formation (DEF), aerated concrete, strength improvement.