Drill cores

After casting test specimens must be prepared such that they are ready for later testing. Specimen can be obtained as drill cores taken from existing buildings shotcrete boxes for quality control measures. Very small scale cores are used for computed tomographic investigations.

Cutting

Drilled cores are shortened to a suitable length for mechanical testing. Prismatic or cubic specimens are cut out of autoclaved aerated concrete blocks or out of no-fines lightweight aggregate concrete elements.

Grinding and Aligning

A plane-parallel end surfaces of specimens is essential for subsequent mchnaical tests. This procedure is necessary also for example for microscopy samples. Concrete specimens impregnated with green resin are polished for a better micro crack detection.

Using a quick-hardening capping compound is an alternative alignment method for specimens like cylinders, cores or bricks. Hard gypsum plaster or sulfur are suitable capping compounds.