New method for testing the sedimentation stability of modern concretes at construction sites

Abstract

Abstract Modern concretes are characterised not only by rising demands on properties but also by increasingly complex compositions. With sophisticated formworks and dense reinforcements, the trend in concrete technology continues towards to self-compacting and easily-compacting concretes. The use of highly effective superplasticizers makes these concretes not only more efficient but also more susceptible to environmental factors and influences. Compliance with desirable fresh and hardened concrete properties is becoming increasingly problematic. In this case, there are no methods for testing today’s concretes, especially the easily-compacting and self-compacting concretes, which are suitable for construction sites. Because of their sensitivity, however, these should be examined separately for their tendency to segregation and, in this context, for their sedimentation stability. For this reason, a test method is currently being developed at the Institute of Construction Materials at the University of Stuttgart, which is intended to examine concretes in particular for this problem. First preliminary test in a simplified procedure have already confirmed the basic idea of testing.