Title: Laboratory Evaluation of the Freezing and Thawing Durability of Marine Limestone coarse aggregate in concrete

Author(s): D. S. Lane and R. C. Meininger

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 1311-1324

Keywords: adsorption; aggregates; air-entrained concretes; limestone; coarse aggregates; concrete durability; freeze-thaw durability; saturation; Materials Research

DOI: 10.14359/2122

Date: 4/1/1987

Abstract:
Air-entrained concretes were subjected to extended freezing-thawing tests to determine the durability of three porous marine limestone coarse aggregates. Control concretes were made with a nonporous limestone. Prior to mixing the concrete, the coarse aggregates were soaked for 24 hr. After initial curing, the specimens were placed in a standard moist room for 13 days until freezing tests began at 14 days' age. Weight change, length change, and dynamic modulus of elasticity were monitored throughout the test. Specimens exposed to the freezing-in-air procedure were subjected to 1000 freezing-thawing cycles without showing significant deterioration. Except for the control group, all specimens subjected to the freezing-in-water procedure began to deteriorate between 250 and 350 cycles, as indicated by increasing length and decreasing modulus of elasticity. Increasing weight of the water-frozen specimens during the first 300 cycles was attributed to water absorption. Calculations suggest that the coarse aggregate in specimens frozen in water had reached 80 to 95 percent saturation when deterioration began. These results emphasize the critical role played by moisture content in determining the freezing-thawing durability of coarse aggregates and the need to develop better methods to evaluate saturation levels during testing with respect to in-place conditions.