ABSTRACT
The test procedure consists of a dynamic part with a varying crack width and a static part with a fixed crack in in a servo hydraulic tensile testing machine (INSTRON 8034) using a temperature box with −20° C. Before placing the specimen into the testing apparatus a first crack in the mortar was induced by a slight bending at room temperature. At one side of the specimen an extensiometer was attached in order to measure the crack width continuously with an accuracy of at least 0,001 mm. The testing machine was controlled by the signals of this strain measuring element.
