F. M. KHALAF
University of Technology, Baghdad
and A. W. HENDRY
University of Edinburgh
Methods of testing masonry materials are currently under review as a result of the development of internationally valid codes of practice such as Eurocode 6. The method of preparation of masonry units for testing in compression varies in different countries. In some cases units are capped with mortar or other material, a packing may be used or the surfaces may be ground flat. Results for five brick and two block types prepared by surface grinding, mortar capping, plywood packing or using dental plaster in a polythene bag show considerable differences between the apparent compressive strengths obtained. For high strength bricks, grinding gave a result some 25% higher than mortar capping and about 60% higher than plywood packing or dental plaster. The differences were smaller for low to medium strength bricks and concrete blocks. Grinding is more convenient than capping and is recommended for bricks. For blocks the method of preparation is less critical and a packing is suggested.