Freezing and Thawing Resistance of Lightweight Aggregate Concrete

One method of confirming in a laboratory the resistance of concrete to frost damage is freezing and thawing testing. The Japan Society of Civil Engineers (JSCE) established a standard method, JSCE G 501, in line with American Society for Testing and Materials (ASTM) C 666 Procedure A. However, whether this method accurately evaluates the resistance of actual concrete structures to frost damage should be open to further discussion. The test method needs modifications particularly for lightwieght aggregate concrete. With aggregate being prewetted in the production process, lightweight aggregate concrete in Japan is doomed to be evaluated as having low durability by the JSCE-specified laboratory tests, as such concrete tends to break up during testing by the freezing expansion of water in critically saturated aggregate. However, a number of actual structures, such as bridge decks where drying proceeds after placing, have exhibited sufficient durability. The authors verify the durability of lightweight aggregate concrete against frost damage by freezing and thawing tests on specimens containing lightweight aggregate with the degree of saturation being modified by drying, as well as by the measurement of the degree of drying and frost resistance of concrete specimens exposed to an outdoor environment in winter.