Title:
Sodium Sulfate Resistance of Fast-Track Portland Cement Concretes
Author(s):
Nader Ghafoori, Hamidou Diawara, and Shane Beasley
Publication:
Materials Journal
Volume:
104
Issue:
6
Appears on pages(s):
585-593
Keywords:
curing; ettringite; gypsum; sodium sulfate resistance; strength
DOI:
10.14359/18962
Date:
11/1/2007
Abstract:
The research study presented herein is intended to examine the sodium sulfate resistance of early opening-to-traffic portland cement concrete. The trial matrixes of two categories of opening-to-traffic times, four cement factors, and three cement types are exposed to very severe external sodium sulfate attack based on ASTM C 1012. The mixtures are examined for fresh properties (slump, bleeding, setting times, and adiabatic temperature), bulk characteristics (unit weight and compressive strength), and resistance to sodium sulfate (expansion and loss in mass and strength). The influence of parameters such as curing age, cement factor, and cement type on sodium sulfate resistance of the selected concretes is discussed. In addition, the expansion of the test specimens is compared with proposed acceptance limits found in the literature based on ASTM C 452 or C 1012. Laboratory test results conclude that, irrespective of cement type, the rate of expansion reduced with increases in cement factor throughout the immersion period. Neither mass of concrete residues nor notable strength loss was found in any opening time fast-track concretes used in the investigation. There was a statistically significant correlation between the sulfate expansion (the dependent variable) and immersion age, cement factor, cement type, and compressive strength (the independent variables).