INFLUENCE OF ALKALI-FREE AND ALKALINE SHOTCRETE ACCELERATORS WITHIN CEMENT SYSTEMS: HYDRATION, MICROSTRUCTURE, AND STRENGTH DEVELOPMENT

Strength development of mixtures accelerated with alkali-free and alkaline admixtures is clarified. Alkali-free admixtures do not interfere with calcium silicatehydrate gel development. A good dissolution of the admixture (e.g., a calciumsulfoaluminate-rich one) causes the ettringites to be homogeneously distributed within the cementitious mass, thus acting as a crack arrester and enhancing the strength. Conversely, an inhomogeneous distribution of the admixture results in the formation of high voluminous ettringite enrichments that weaken the microstructure and result in the strength decrease of the alkali-free accelerated mixtures. Addition of the alkaline accelerator delays the hydration of the calciumsilicate components to calciumsilicatehydrate gel and its densifying process. As a result, a general high porosity persists up to 6 months, resulting in the lowest strength among the accelerated mixtures.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/13846872
• Corporate Authors:

  American Concrete Institute (ACI)

  38800 Country Club Drive
  Farmington Hills, MI  United States  48331
• Authors:
  • Paglia, CSB
  • Wombacher, F J
  • Bohni, H K
• Publication Date: 2004-9

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 352-357
• Serial:
  • ACI Materials Journal
  • Volume: 101
  • Issue Number: 5
  • Publisher: American Concrete Institute (ACI)
  • ISSN: 0889-325X
  • Serial URL: https://www.concrete.org/publications/acimaterialsjournal.aspx

Subject/Index Terms

• TRT Terms: Admixtures; Alkalinity; Calcium silicate; Concrete construction; Ettringite; Hydration; Microstructure; Shotcrete; Silica gel; Structural materials
• Subject Areas: Bridges and other structures; Design; Highways; Materials; I24: Design of Bridges and Retaining Walls; I32: Concrete;

Filing Info

• Accession Number: 00979777
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 5 2004 12:00AM