The fire resistance of concrete structures is generally good, but for some types of concrete fire spalling can reduce the fire resistance significantly. Therefore, methods are needed to predict whether a concrete will spall when exposed to fire and the severity of spalling.

The objective of the present project was to develop an intermediate scale test method for the evaluation of the spalling behavior of concrete. The test method shall be cost effective and enable screening of different concretes before a full scale approval test is performed. A number of different intermediate scale test methods have been evaluated regarding the precision to reproduce the spalling behavior of that observed in full scale tests.

Of the different test specimen shapes and methods, a circular test specimen where the concrete is casted in a steel tube has shown the best correlation to the full scale tests performed. This specimen is easy to produce, and the fire test can be performed on a small furnace.