This thesis presents the results from a series of experiments in which moisture is transported across several bonded and natural contact interfaces between two materials, i.e. autoclaved aerated concrete (AAC) and mortar. All experimental results conclusively show that an assumption of perfect hydraulic contact is an over simplification of the interfacial phenomena. Instead, this thesis recommends "imperfect hydraulic contacts" in all situations, bonded as well as natural contact. Based on the above recommendation, this thesis introduces a concept of "mismatching resistance" to mathematically describe the imperfect contact. Physically it corresponds to a resistance offered by the interface to moisture transport due to misalignment of the pore structures on either side of the interface. A mathematical model of moisture transport was developed and the mismatching resistance was incorporated in it to account for interfacial phenomena. A numerical model was subsequently used to simulate moisture transport in building assemblies. The moisture transport experiments conducted with AAC and mortar were simulated with the numerical model. The results from the gamma ray measurements were used to optimize the mismatching resistance for each experimental situation. The mismatching resistance so optimized was found to depend on moisture content and also showed directionality. With one set of optimized mismatching resistances for each experimental situation, excellent agreement was found between the measured and simulated transient moisture distributions in all cases. This thesis also presents the results of a parametric study to investigate the sensitivity of predictions regarding material properties and interface imperfection. (Abstract shortened by UMI.).

The knowledge of moisture migration inside building materials and construction building components is decisive for the way they behave when in use. The durability, waterproofing, degrading aspect and thermal behaviour of these materials are strongly influenced by the existence of moisture within their interior, which provoke changes in their normal performance, something that is normally hard to predict. Due to the awareness of this problem, the scientific community have per-formed various studies about the existence of moisture inside porous materials. The complex aspects of moisture migration phenomenon tended to encompass monolithic building elements, since the existence of joints or layers contributes to the change of moisture transfer along the respective building element that contribute to the change of mass transfer law. The presentation of an experimental analyses concerning moisture transfer in the interface of material that makes up masonry is described in such a way as to evaluate the durability and/or avoid building damages. In this work it was analysed, during the wetting process, the influence of different types of interface, commonly observed in masonry, such as: perfect con-tact, joints of cement mortar, lime mortar, and the air space interface. The results allow the calculation of the hygric resistance. With these results, it is possible to use any advanced hygrothermal simulation program to study the water transport in building elements, considering different interfaces and their hygric resistance.

This work presents an extensive experimental characterisation of two different ceramic brick blocks with different interface, at different heights, during the drying process. First, a laboratory characterization of the building material used (ceramic bricks and different mortars) is presented, showing their hygrothermal, mechanical and thermal properties, namely, bulk porosity and density, water vapour permeability, capillary absorption, retention curve, moisture diffusivity as a function of moisture content and thermal conductivity. Moreover, the moisture transfer in multi-layered systems was analysed in detail taking into account the interface contact between the building elements.

Note: New editions of this book have been published: the 2nd edition in 2012, the 3rd edition in 2017, and the 4th edition in September 2023. Bad experiences with construction quality, the energy crises of 1973 and 1979, complaints about 'sick buildings', thermal, acoustical, visual and olfactory discomfort, the move towards more sustainability, have all accelerated the development of a field, which until 35 years ago was hardly more than an academic exercise: building physics. Through the application of existing physical knowledge and the combination with information coming from other disciplines, the field helps to understand the physical performance of building parts, buildings and the built environment, and translates it into correct design and construction. This book is the result of thirty years teaching, research and consultancy activity of the author. The book discusses the theory behind the heat and mass transport in and through building components. Steady and non steady state heat conduction, heat convection and thermal radiation are discussed in depth, followed by typical building-related thermal concepts such as reference temperatures, surface film coefficients, the thermal transmissivity, the solar transmissivity, thermal bridging and the periodic thermal properties. Water vapour and water vapour flow and moisture flow in and through building materials and building components is analyzed in depth, mixed up with several engineering concepts which allow a first order analysis of phenomena such as the vapour balance, the mold, mildew and dust mites risk, surface condensation, sorption, capillary suction, rain absorption and drying. In a last section, heat and mass transfer are combined into one overall model staying closest to the real hygrothermal response of building components, as observed in field experiments. The book combines the theory of heat and mass transfer with typical building engineering applications. The line from theory to application is dressed in a correct and clear way. In the theory, oversimplification is avoided. This book is the result of thirty years teaching, research and consultancy activity of the author.

One in three homes, on average, suffer from excessive dampness and mould proliferation, with significant health and economic impacts. The combination of new construction methodologies, stricter airtightness requirements and the changing social and cultural context that influences the way we live inside buildings has created unprecedented challenges for the built environment. In modifying indoor and outdoor environments and the building envelopes that serve as a filter between the two, we are changing the physical parameters of the ways in which buildings behave and respond to climatic stimuli. Understanding and predicting the way in which buildings and moisture may interact should be an important step in the design process, aiming to minimise possible negative long-term consequences. Understanding and predicting the way in which buildings and moisture may interact is, today more than ever, essential yet difficult, as the experience of the past has lost its applicability. Moisture-related issues never have a simple solution, since they involve multiple factors, including design, construction, maintenance, materials, climate and occupation pattern. Thus, while the topic is attracting growing attention among researchers, designers and practitioners, the pace with which actual change is occurring is still too slow. Moisture and Buildings provides a critical overview of current research, knowledge and policy frameworks, and presents a comprehensive analysis of the implications of moisture and the importance of accounting for it during the design process. It responds to the urgent need for a systematic organization of the existing knowledge to identify research gaps and provide directions for future developments. The ultimate goal is to increase awareness of the multifaceted implications of hygrothermal phenomena and promote integrated design processes that lead to healthier and more durable constructions. Presents advanced knowledge on hygrothermal processes and their interaction with buildings Integrates the three key areas of moisture transport and its impact on buildings, including durability, human health and comfort Considers the most useful computational tools for assessing moisture and building interactions Includes a section on the main European, American and Australian building codes Explains the risks of mold growth to human health, including growth models to assessment methods

This book provides a collection of recent research works related to new trends and pathologies associated with concrete structures, in order to contribute to the systematization and dissemination of knowledge related to moisture transport, durability, construction pathology, diagnostic techniques, and the most recent advances in this domain. The book is divided into five chapters that intend to be a resume of the current state of knowledge for benefit of professional colleagues, scientists, students, practitioners, lecturers, and other interested parties to network. At the same time, these topics will be going to the encounter of a variety of scientific and engineering disciplines, such as civil, mechanical, and materials engineering.