VERSTRYNGE, ELS1; PYKA, GRZEGORZ2; WEVERS, MARTINE3; VAN BALEN, KOEN4

1) Dr. ir.-arch., KU Leuven, Civil Engineering Department, els.verstrynge@bwk.kuleuven.be

2) ir., KU Leuven, Department of Metallurgy and Materials Engineering, gregory.pyka@mtm.kuleuven.be

3) Prof. Dr. ir., KU Leuven, Department of Metallurgy and Materials Engineering, martine.wevers@mtm.kuleuven.be

4) Prof. Dr. ir.-arch., KU Leuven, Civil Engineering Department, koenraad.vanbalen@bwk.kuleuven.be

Moisture is known to have a negative effect on the long-term behaviour of masonry and to decrease its mechanical characteristics. The presented study focuses on the influence of moisture on the mechanical behaviour of ferruginous sandstone in order to understand and quantify this effect. Thereby, the influence of moisture on the mechanical behaviour of ferruginous sandstone is investigated on different levels in order to obtain a more detailed picture of the acting processes: micro (sandstone inner structure) – meso (sandstone blocks) – macro (masonry). The presented paper focuses on the micro level. Compressive tests under sustained loading are performed on dry and saturated sandstone samples. At specific loading steps, a 3D image is made of the specimen’s inner structure by means of microfocus computed tomography (microCT) to visualise the fracture progress during the stepwise compressive test. It was observed that crack initiation in saturated samples could be visualised at an earlier stage during the compression tests due to their decreased internal friction and less brittle behaviour. The decrease of mechanical characteristics, such as strength and stiffness, was found to be more pronounced for lower-quality ferruginous sandstone.

Keywords: micro-computed tomography, ferruginous sandstone, mechanical behaviour, moisture, creep behaviour, experimental analysis