Title: Colloidal Silica Admixture

Author(s): Jon S. Belkowitz, Whitney B. Belkowitz, Matthew A. Best, and Frank T. Fisher

Publication: Concrete International

Volume: 36

Issue: 7

Appears on pages(s): 59-65

Keywords: ASR, concrete, fly ash, pavement

DOI:

Date: 7/1/2014

Abstract:
Colloidal silica (CS) is generally used as a finishing aid and densifier for concrete floors. Recently, tests were undertaken to evaluate CS as an admixture to mitigate alkali-silica reactivity (ASR) in dosages that would not retard early concrete strength development. The article presents development and evaluation of concrete mixtures with CS admixture in the laboratory and on a commercial job site. Field and laboratory tests showed that CS provided increased early strength of Class F fly ash mixtures while reducing ASR expansion.