Report on Cooperative Freezing-and-Thawing Tests of Concrete, 1959

(1959) Report on Cooperative Freezing-and-Thawing Tests of Concrete, 1959. Transportation, Department of

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Abstract

A program of cooperative freezing-and-thawing tests of concrete specimens was conducted by thirteen laboratories using the four ASTM Tentative Methods of Test. Three concrete mixtures were used, involving different aggregates and two different air contents. Large variations in durability were found for the same concrete mixture and for tests by the same method, both within and between laboratories. It is indicated that these were due both to differences in the concretes as prepared in the laboratories and in treatment of the specimens by a given test method. Differences in specimens consisted mainly in unexpectedly large variations in air content and airvoid characteristics revealed _by microscope measurements of the air-void systems in some of the test specimens. Differences in the treatments were greatest in the methods involving freezing in air, and were probably due in part to unequal amounts of drying during freezing. A statistical examination of the data and a comparison with previous programs are presented. It is concluded that these methods provide useful procedures for comparing the relative durability of different concretes within a given laboratory; that a wide variation of results in the middle range of durability appears to be a normal characteristic of the methods; that the data do not permit recommending one test method over the others for all purposes; and that the ability of concrete to withstand a severe laboratory freezing-and-thawing test is probable indication of a high degree of durability.