Designing insulation filled masonry blocks against hygrothermal deterioration

摘要

Due to increasingly stringent requirements in building energy performance, further development of fired clay masonry blocks are essential nowadays for the manufacturers. One of the possible directions for improving thermal performance of the masonry blocks is to fill them with insulating materials. The currently developed bricks are most commonly containing mineral wool thermal insulation filler. The main criteria for manufacturers to develop their products are thermal performance and manufacturability, which leads to unsolved hygrothermal questions. While the filler materials have low thermal conductivities, they may deteriorate in high humidity environment and due to freeze-thaw cycles. The aim of this research is to test existing filled building blocks, to prevent hygrothermal deterioration. The study compares one-dimensional monthly based steady state Glaser method with steady state two-dimensional hygrothermal simulations and dynamic multi-dimensional conjugated heat and moisture transfer simulations. The calculations were made considering Central European Budapest climate. Hygrothermal material properties were measured in laboratory. After the calculations, results show that effective thermal transmittance, maximum freezing depth from the external surface of the plastered masonry blocks and the number of freeze-thaw cycles during a year vary depending on the facade's orientation. The possible freezing zone can reach one third of the masonry block from the external side, and affect the thermal performance of the bricks. The outermost insulation layers of the masonry blocks therefore must selected to bear freeze-thaw cycles and high humidity because of protection aspects. The new aspects of this study can be used to extend the application limits of insulation filled masonry blocks and design these type of masonry blocks against hygrothermal deteroriation.