11:15am - 11:18am
Dependency of conservation conditions of Takase stone Buddha, Oita, Japan, on anisotropy of liquid water diffusivity
1Kindai University, Japan; 2Sekisuihouse Co., Ltd., Japan; 3Nara National Research Institute for Cultural Properties, National Institutes for Cultural Heritage; 4Kyoto University
Takase Stone Buddhas is one of the important old stone buddha sculptures curved into the inner wall of the caves in Oita, Japan. It is located in a cave curved into the cliff of a hill of volcanic tuff. In general, because the cave is currently protected from rain and direct solar radiation by the roof shelter and waterproof treatment, the Buddhas is well conserved and no currently ongoing weathering can be clearly observed. However, because of a high ground water level, there is a concern in the influence of water evaporation at and near the surface of the stone buddhas and the wall of the cave on their deterioration. This paper reports on our long-term field survey of conservation environment and numerical analyses of heat and moisture transport in the cliff and stone buddhas. The field survey provides a yearly data set of the conservation environment that is used as input of the succesive numerical simulation of heat and water transport in the material. Finally, the past preservation and maintenance project such as the roof shelter and waterproof treatment taken in the recent years are evaluated and the need of a further preservation and maintenance project such as waterproof treatment for the exterior wall facing to the west is discussed based on results of the numerical analyses. The simulations results show that conservation conditions of Takase stone Buddha strongly depends on the anisotropy of liquid water diffusivity of the tuff stone.
11:18am - 11:21am
An impact of moisture content on the air permeability of the fibrous insulation materials
1University of Warmia and Mazury in Olsztyn, Poland; 2University of Liège, Belgium
Due to the statistics, fibrous materials account around 50% of the insulation material market. They are characterized by good thermal properties, including a low thermal conductivity. The big advantage is the possibility of easy installation in building elements, good adhesion to the surrounding walls. On the other hand, these materials are susceptible to air filtration. Effective air and wind protection of the building envelope, eliminate this problem. However, there are many buildings where this protection has not been applied. Therefore, it is important to estimate how the problem of air filtration contributes to the thermal losses of the building. The air transport properties of fibrous materials are primarily dependent on the density.
The authors investigated the effect of moisture on the air permeability of chosen loose fibrous materials: mineral wool, wood wool and cellulose fibers. The results show how the moisture changes air transport in the materials.
The article will present the laboratory investigation of the moisture influence on air permeability of chosen materials. The results will be compared with the simulation.
11:21am - 11:24am
The effect of silanes as integral hydrophobic admixture on the physical properties of cement based materials
Lodz University of Technology, Poland
Organosilicon compounds such as silanes are used as hydrophobic admixtures for internal hydrophobization of cement-based materials. Hydrophobization is a process of implementing the hydrophobic agents into the porous structure. As a result of a chemical reaction, its fills voids preventing or restricting the penetration of water or moisture. The key function of the internal hydrophobization is to protect porous materials from adverse water effects, thereby increasing their durability by reducing the water absorption. The aim of the study was to define the possibility of using silane-based agents as admixtures to improve a durability of cement-based materials. The influence of silane-based admixtures on physical properties of cementitious material was determined. The measurements have been performed on cement paste and mortars specimens which were composed of Portland cement CEM I 42.5R with water-to-cement ratio equal to 0.5. The paper concerns the influence of silane on the mechanical (compressive strength) and transport properties (water absorption coefficient) of cement mortar. The impact of silane on the amount of ice formed in the pores of the cement paste during the freezing of water was observed by differential scanning calorimetry (DSC). The determination of the sorption isotherms of cement paste with silane-based admixture, were performed using Dynamic Vapour Sorption method (DVS). The research was supplemented with the microstructure analysis of cement paste and mortar which was monitored by mercury intrusion porosimetry (MIP). The obtained results leads to the conclusion that internal hydrophobization might be a great alternative to surface hydrophobization. The significant decrease of the water absorption coefficient, acceptable decrease in compressive strength and negligible changes in microstructure of cementitious material were determined. Therefore, one can obtained that it is possible to use organosilicon compounds as hydrophobic admixtures to improve the water resistance of cementitious materials and thus their durability and long-life properties.
11:24am - 11:27am
Identifying suitable inputs for the moisture risk assessment of waterproofed cavity walls with surface waterproofing treatment
1UCL Institute for Environmental Design and Engineering, University College London, United Kingdom; 2UK Centre for Moisture in Buildings, United Kingdom; 3UCL Energy Institute, University College London, United Kingdom
Cavity wall insulation is one of the most cost-effective energy efficiency solutions for dwellings in the UK. However, most of the insulation materials commonly used are not suitable for unprotected cavity walls that are subjected to wind driven rain in exposed areas. This is due to the increased risks of water penetration leading to wet insulation within the wall, damp inner walls, ineffective insulation and freeze-thaw damage occurring at the outer surface.
The application of certain water repellent surface treatments directly to the outer surface of the wall may reduce rain penetration and associated risks. However, there is limited evidence on the effectiveness of water repellent surface treatments, when these are applied onto cavity walls with an unprotected outer brick layer under high wind-driven rain loads.
This paper presents the performance of cavity walls hygrothermal simulations of cavity walls under controlled conditions, and a comparison between the model predictions and laboratory measurements. The analysis considers measured values for the water absorption coefficient and the vapour permeability of brick and mortar.
The water uptake predicted in the hygrothermal simulations is minimal, and in disagreement with the experimental work. The findings suggest that water infiltration at joints is the dominant mechanism for rainwater penetration, in agreement with recent studies on uninsulated cavity walls, and that rainwater infiltration should be considered in the moisture risk assessment for waterproofed cavity walls.
11:27am - 11:30am
Interstitial condensation in Chinese residential buildings: cliché or challenge?
1School of Architecture and Urban Planning, Chongqing University, Chongqing , China; 2Key Laboratory of New Technology for Construction of Cities in Mountain Area, Ministry of Education, Chongqing University, 400045 Chongqing, PR China
Abstract. In this paper, we compare the predictions of interstitial condensation by the steady-state method and the transient method under different climate conditions in China. Simulations reveal significant differences between the two methods, and the wind-driven rain also plays an important role. As a result, the transient hygrothermal simulation considering wind-driven rain should be recommended instead of the steady-state method for predicting interstitial condensation under complicated climate conditions.
11:30am - 11:33am
Review of fungi in buildings and their ability to methylate chlorophenol into malodorous chloroanisoles.
Lund University, Sweden
A source of indoor malodor in older buildings are chloroanisoles, a methylation from chlorophenols. Chlorophenols were commonly used in wood preservatives 50 years ago which were used to treat construction details exposed to high moisture loads. The methylation process requires a methylator in the form of fungi or bacteria in conjunction with adequate growth conditions for said fungi. The food industry has a history of issues with chloroanisoles contaminating different food items. They have conducted research on fungi species found in the packaging materials or surfaces in proximity and their ability to methylate various chlorophenols. Different species of fungi are present in many places, including various building materials. A comparison has been made in this study between fungi able to methylate chlorophenols and their potential occurrence in wooden construction details in buildings. Two species were found to be considered strong methylators and also commonly found in wooden constructions, Aspergillus versicolor and Paecilomyces variotii. The properties of these fungi will be used for future studies of the conditions achievable in wooden constructions where the historic wood preservatives were likely used.
11:33am - 11:36am
Capillary rising damp in Venetian context: state of the art and numerical simulations
University IUAV of Venezia, Italy
The fragility of Venice and the alteration of its buildings and materials are linked to the floods, observed since ancient times and emphasized in recent years; the periodic sea level rise, accompanied by rising damp, are the main causes of the alteration of the facades of Venetian buildings.
In particular, the rising damp causes a series of complex diseases in the historic buildings, such as physical decay, chemical or biological, with loss of aesthetic and/or economic value. In addition, greater heat dispersion (with improvement can be quantified near 30-50%) and reduced thermal comfort can also occur in interior spaces, with consequent risks for human health. This is a sign of “Sick Building Syndrome”.
Currently it is very important to develop models for assessing the vulnerability of assets and to manage sustainable plans related to maintenance processes and activities, satisfying the requirements of effectiveness and compatibility.
Moisture is very common in historic buildings, where it transfers from the ground to the masonry due to a high gradient of water concentration in the soil. The main factors from which this phenomenon derives are of different origins: the type of material and its performance, construction or geometric technology, concentration of salts in the water and surrounding climatic conditions. These properties will give rise to non-uniform rising damp.
This paper reports a series of research on numerical models performed with the WUFI 2D software, useful for understanding the different behavior of rising damp in relation to materials or masonry structures. The construction techniques and typical materials used in Venetian buildings were investigated, such as clay brick walls, lime plaster, marmorino and cocciopesto and also the Istrian stone, adopted mainly to limit the capillary rise also caused by the phenomenon of “acqua alta”.