The standard restrained ring test (ASTM 1581-04) is a simple, economical method to evaluate a concrete mixture s susceptibility of shrinkage cracking. Unfortunately, the test only provides restraint against samples that shrink and can not be used to consider cases in which expansion occurs. Further, the conventional restrained ring test does not consider cases in which the concrete undergoes large variations in temperature since the restraint changes dimension under heating and cooling. This paper describes a test that was designed to overcome both of these limitations. This paper describes the development of a dual ring test that provides restraint for both shrinkage and expansion. In addition, the test has incorporated the ability to study thermal stresses by using a restraining ring that is stable during temperature changes. This paper will discuss the design and construction of the test and will present preliminary data that characterizes its ability to quantify and evaluate restrained expansive, shrinkage, and thermal stresses.
Citation: Cement and Concrete Composites
Pub Type: Journals
Autogenous shrinkage, building technology, concrete, expansion, restrained shrinkage, thermal cracking.