Investigation of the Effectiveness of Siloxane Hydrophobic Injection for Renovation of Damp Brick Masonry
Experimental investigation of the effect of
hydrophobic injection on siloxane basis on the properties of oldfashioned
type of ceramic brick is presented in the paper. At the
experimental testing, the matrix density, total open porosity, pore size
distribution, sorptivity, water absorption coefficient, sorption and
desorption isotherms are measured for the original, as well as the
hydrophobic-injection treated brick. On the basis of measured data,
the functionality of the hydrophobic injection for the moisture ingress
prevention into the studied ceramic brick is assessed.
Brick masonry, siloxane hydrophobic injection,
moisture ingress, functionality testing.
Experimental and Computational Analysis of Hygrothermal Performance of an Interior Thermal Insulation System
Combined experimental and computational analysis of
hygrothermal performance of an interior thermal insulation system
applied on a brick wall is presented in the paper. In the experimental
part, the functionality of the insulation system is tested at simulated
difference climate conditions using a semi-scale device. The
measured temperature and relative humidity profiles are used for the
calibration of computer code HEMOT that is finally applied for a
long-term hygrothermal analysis of the investigated structure.
Additional thermal insulation, hygrothermal
analysis, semi-scale testing, long-term computational analysis
Effect of Fine-Ground Ceramic Admixture on Early Age Properties of Cement Paste
Properties of cement pastes with fine-ground ceramics
used as an alternative binder replacing Portland cement up to 20% of
its mass are investigated. At first, the particle size distribution of
cement and fine-ground ceramics is measured using laser analyser.
Then, the material properties are studied in the early hardening
period up to 28 days. The hydration process of studied materials is
monitored by electrical conductivity measurement using TDR
sensors. The changes of materials- structures within the hardening are
observed using pore size distribution measurement. The compressive
strength measurements are done as well. Experimental results show
that the replacement of Portland cement by fine-ground ceramics in
the amount of up to 20% by mass is acceptable solution from the
mechanical point of view. One can also assume similar physical
properties of designed materials to the reference material with only
Portland cement as binder.
Fine-ground ceramics, cement pastes, early age
properties, mechanical properties, pore size distribution, electrical
Effect of Temperature of Exposure on Properties of Cement Mortar with MSWI Bottom Ash
Effect of high temperature exposure on properties of cement mortar containing municipal solid waste incineration (MSWI) bottom ash as partial natural aggregate replacement is analyzed in the paper. The measurements of mechanical properties, bulk density, matrix density, total open porosity, sorption and desorption isotherms are done on samples exposed to the temperatures of 20°C to 1000°C. TGA analysis is performed as well. Finally, the studied samples are analyzed by IR spectroscopy in order to evaluate TGA data.
Cement mortar, high temperature exposure, MSWI bottom ash, natural aggregate replacement, mechanical properties
Hygric Performance of a Sandstone Wall Retrofitted with Interior Thermal Insulation
Temperature, relative humidity and overhygroscopic
moisture fields in a sandstone wall provided with interior thermal
insulation were calculated in order to assess the hygric performance
of the retrofitted wall. Computational simulations showed that during
the time period of 10 years which was subject of investigation no
overhygroscopic moisture appeared in the analyzed building
envelope so that it performed in a satisfactory way from the hygric
point of view.
Sandstone wall, interior thermal insulation,
moisture, computational modeling.
Investigation of Water Vapour Transport Properties of Gypsum Using Genetic Algorithm
Water vapour transport properties of gypsum block
are studied in dependence on relative humidity using inverse analysis
based on genetic algorithm. The computational inverse analysis is
performed for the relative humidity profiles measured along the
longitudinal axis of a rod sample. Within the performed transient
experiment, the studied sample is exposed to two environments with
different relative humidity, whereas the temperature is kept constant.
For the basic gypsum characterisation and for the assessment of input
material parameters necessary for computational application of
genetic algorithm, the basic material properties of gypsum are
measured as well as its thermal and water vapour storage parameters.
On the basis of application of genetic algorithm, the relative
humidity dependent water vapour diffusion coefficient and water
vapour diffusion resistance factor are calculated.
Water vapour transport, gypsum block, transient
experiment, genetic algorithm.
Interaction of Building Stones with Inorganic Water-Soluble Salts
Interaction of inorganic water-soluble salts and building stones is studied in the paper. Two types of sandstone and one type of spongillite as representatives of materials used in historical masonry are subjected to experimental testing. Within the performed experiments, measurement of moisture and chloride concentration profiles is done in order to get input data for computational inverse analysis. Using the inverse analysis, moisture diffusivity and chloride diffusion coefficient of investigated materials are accessed. Additionally, the effect of salt presence on water vapor storage is investigated using dynamic vapor sorption device. The obtained data represents valuable information for restoration of historical masonry and give evidence on the performance of studied stones in contact with water soluble salts.
Moisture and chloride transport, sandstone, spongillite, moisture diffusivity, chloride diffusion coefficient.
Secondary Effects on Water Vapor Transport Properties Measured by Cup Method
The cup method is applied for the measurement of water vapor transport properties of porous materials worldwide. However, in practical applications the experimental results are often used without taking into account some secondary effects which can play an important role under specific conditions. In this paper, the effect of temperature on water vapor transport properties of cellular concrete is studied, together with the influence of sample thickness. At first, the bulk density, matrix density, total open porosity and sorption and desorption isotherms are measured for material characterization purposes. Then, the steady state cup method is used for determination of water vapor transport properties, whereas the measurements are performed at several temperatures and for three different sample thicknesses.
Water vapor transport, cellular concrete, cup
method, temperature, sample thickness.
Effect of Environmental Conditions on Energy Efficiency of AAC-based Building Envelopes
Calculations of energy efficiency of several AACbased
building envelopes under different climatic conditions are
presented. As thermal insulating materials, expanded polystyrene and
hydrophobic and hydrophilic mineral wools are assumed. The
computations are accomplished using computer code HEMOT
developed at Department of Materials Engineering, Faculty of Civil
Engineering at the Czech Technical University in Prague. The
climatic data of Athens, Kazan, Oslo, Prague and Reykjavík are
obtained using METEONORM software.
climatic conditions, computational simulation,
energy efficiency, thermal insulation
Mechanical and Hydric Properties of High- Performance Concrete Containing Natural Zeolites
Mechanical and water transport properties of high
performance concrete (HPC) containing natural zeolite as partial
replacement of Portland cement are studied. Experimental results
show that in the investigated mixes the use of natural zeolite leads to
an increase of porosity, decrease of compressive strength and
increase of moisture diffusivity and water vapor diffusion coefficient,
as compared with the reference HPC. However, for the replacement
level up to 20% of the mass of Portland cement the concretes still
maintain their high performance character and exhibit acceptable
water transport properties. Therefore, natural zeolite can be
considered an environmental friendly binder with a potential to
replace a part of Portland cement in concrete in building industry.
Natural zeolites, high-performance concrete; hydric
properties, mechanical properties
Lime-Pozzolan Plasters with Enhanced Thermal Capacity
A new type of lightweight plaster with the thermal capacity enhanced by PCM (Phase Change Material) addition is analyzed. The basic physical characteristics, namely the bulk density, matrix density, total open porosity, and pore size distribution are measured at first. For description of mechanical properties, compressive strength measurements are done. The thermal properties are characterized by transient impulse techniques as well as by DSC analysis that enables determination of the specific heat capacity as a function of temperature. The resistivity against the liquid water ingress is described by water absorption coefficient measurement. The experimental results indicate a good capability of the designed plaster to moderate effectively the interior climate of buildings.
Lime-pozzolan plaster, PCM addition, enhanced thermal capacity, DSC analysis.
Thermal Properties of Lime-Pozzolan Plasters for Application in Hollow Bricks Systems
The effect of waste ceramic powder on the thermal properties of lime-pozzolana composites is investigated. At first, the measurements of effective thermal conductivity of lime-pozzolan composites are performed in dependence on moisture content from the dry state to fully water saturated state using a pulse method. Then, the obtained data are analyzed using two different homogenization techniques, namely the Lichtenecker’s and Dobson’s formulas, taking into account Wiener’s and Hashin/Shtrikman bounds.
Waste ceramic powder, lime-pozzolan plasters, effective thermal conductivity, homogenization techniques.