Impacts of sealing methods on the reliability of water absorption tests: Investigation of combination of sealing method and building materials

During water absorption tests aimed at determining the liquid-water transfer properties of porous building materials, the side surfaces of a specimen are usually covered with vapor-impermeable materials, such as wrap, adhesive, resin, or tape. However, the use of a variety of sealing materials has been identified as a potential source of errors in the results of water absorption tests. The significance of these errors in relation to different combinations of building and sealing materials remains unclear. To develop more reliable testing methods, this study investigated the impact of the sealing method on the water absorption test results for building materials. This was achieved by analyzing the effects of various potential error factors and their dependence on the combination of sealing methods and building materials. Water absorption tests were conducted using three types of building materials and various sealing methods, including plastic wrap, three types of resin, and aluminum tape. The results indicated that the decrease in water absorption resulting from resin penetration into the specimen could not be disregarded, and was influenced by factors, such as resin curing time, viscosity, and material characteristics. Furthermore, the use of adhesive tape could lead to water absorption through the gap between the specimen and the tape, resulting in a significant overestimation of the water absorption of the aerated concrete specimen. Plastic wrap and tape were identified as the most reliable sealing materials for building materials employed, provided they do not come into contact with the water surface, which could lead to capillary uptake between the specimens and sealing material.