ABSTRACT
The analysed sleepers are produced in the BBRV technology from HPC with the strength in the range from 80 to 90 MPa, and the content of high strength cement CEM I 52.5 as a rule over 450 kg/m3. Mechanical anchorage in sleepers are based on the system of smooth 8 bars anchorage (diameter of 7 mm) executed with the anchorage plates on the ends of the strings.
This paper presents the results of the diagnostic analysis performed showing that the cracking was due to the occurrence of Delayed Ettringite Formation (DEF) in the concrete. The DEF was caused by the employed steam heat-curing regime in combination with the high cement content in the concrete mix design. The observed mechanism of destruction is another phenomenon that is described in the known literature [Santos Silva A. 2008].
