Title:
Sand box
Author(s):
Claude Boulay and Francois De Larrard
Publication:
Concrete International
Volume:
15
Issue:
4
Appears on pages(s):
63-66
Keywords:
capping (of concrete test specimens); compressive strength; high-strength concretes; laboratories; mortars (material); test equipment; testing; General
DOI:
Date:
4/1/1993
Abstract:
The capping of high-performance concrete (HPC) cylinders is a critical point in getting reliable strength data. First, it is shown that the use of bonded caps (e.g., sulfur mortar) is no longer valid for very-high-strength concrete, as the cap material is weaker than the concrete to be tested. The authors have modified Carrasquillo's "unbonded cap" technique by replacing the neoprene pads with dry and compacted sand. Reproducibility has been checked in a seven- laboratory round-robin test. Practical applicability has been demonstrated by using the sandbox for the quality control of the "Pont de Normandie" HPC.