Edinburgh Napier University

  This series of study focused on analysing and assessing the changes of the physical and chemical characteristics of the surfaces of the masonrystones and bricks during the sandblasting cleaning process by conducting various physical and chemical tests. Seven masonry stones and bricks were adopted, including yellow sandstone, red sandstone, limestone, marble, granite, white clay brick and yellow clay brick. The physical testing included evaluating the cleaning degree, determining the Vickers hardness, and detecting the water absorption. Using a digital imaging analysis method, the greyscale and cleanness were introduced to quantitatively assess the effectiveness of masonry building cleaning and confirmed to be useful and appropriate. The cleanness analysis, together with the hardness and water absorption tests showed that a masonry stone or a brick with a higher cleaning degree corresponded to a brighter and harder stone surface. In general, the physical properties were found to vary largely during the building cleaning.