ABSTRACT
The paper reports on a study of cracking accompanying the expansion of a lineal steel element embedded in selected types of concrete. The tests involved the pulling of a cone-shaped steel bar through 50 mm thick sawn disks of plain and steel fibre concretes. Basic examinations, comprising acoustic emission and deformation measurements, have been carried out for young (7 days old) and standard (28 days old) specimens. Among other things, tests have shown the mechanisms of micro- and macrocrack formation in different concretes to be properly reflected by the acoustic emission parameters. Simultaneously, the significant role of fibres was established in controlling the cracking behaviour. Due to their ability of arresting microcracks and inhibiting their growth, a delay of the macrocrack formation has been observed. Availing oneself of this phenomenon could be essentially important for reducing the corrosion risks of reinforced concrete constructions under unfavourable conditions and thereby increasing their serviceability life.
