Investigation of the properties and behaviour of ancient and newly constructed mudbricks from the ancient walls of Eleusis

Abstract

The paper presents the test results from the investigation of the nature and mechanical behaviour of mudbricks from the ancient mudbrick wall of Eleusis in Attica, Greece. The mudbrick wall remains preserved to date in the site of Eleusis are some of the largest preserved in Greece. Small fragments of mudbricks were taken to the laboratory for experimental investigation. Testing included index tests toclassify the soil material the mudbricks were made of, mineralogical analyses of their fines’ content, mechanical testing suitable for the nature of the materials and the ability to trim the samples without causing damage and measurements of suction on samples as they were obtained, further dried, or rewetted. The soil material used for ancient mudbrick construction was a silty sand to sandy silt with a small fraction clay content, with marginally plastic to non-plastic fines. Dry unit weight was found to be close to the dry unit weight of fresh mudbrick material after being compacted with a minimum compaction energy of only 45 kNm/m3 and left to dry to residual water content conditions. Similarly, field water content was found close to the residual water content of these recompacted soil samples. Consequently, unconfined compression strength was found very high corresponding to the residual water content condition, with similarly high cohesion obtained from direct shear tests and a very high yield stress under one-dimensional conditions of loading.