Jitka Hroudová

Study of Behaviour of Advanced Silicate Materials for Thermal and Moisture Rehabilitation of Buildings

The article describes the results of research work carried out in cooperation between the Faculty of Civil Engineering in Brno and the Faculty of Civil Engineering in Vienna concerning the development and study of the behaviour of heat-insulation plasters on a silicate basis, in particular in the area of the transfer of heat and moisture in their structures. The main objective was to determine the capillary activity of the thermal moisture behaviour of the developed materials which can be source material for the further part of the research solution addressing the simulation of the behaviour of these thermal-insulating plasters in real constructions.

Investigation of Anti-noise Absorptions Walls Development with Utilization of Waste from Agriculture

Along side with the fast infrastructure development such as highways, roads and railroad tracks there is increasing stress on protection against noise produced by these line sources. In general it seems to be the most efficient way to reduce noise by building anti-noise walls along line sources of traffic noise. Anti-noise walls absorb the noise and protect from distribution to surrounding environment. The paper describes possibilities of use of waste from production of technical hemp for production of anti-noise walls with high level of sound absorption. Advantages of these walls are not only good acoustic properties but also lower price and utilization of environmental friendly material. The used technical hemp is easily renewable material source; technical hemp can be substituted by another similar material typical for the particular area or more easily accessible.

Development of Concretes with Resistance to High Temperatures in the Czech Republic and Surrounding European Countries

The resistance of concrete constructions to high temperatures at present is a much monitored issue for many scientific teams and experts in the stated area. This fact is mainly caused by fatal consequences originating in the case when concrete constructions are loaded by the effect of fire and consequent loss of their load-bearing capacity, for the population and the environment of our planet, in which we live in. The development of society goes hand in hand with the development of new building materials and as a consequence the requirements for building constructions increase which bring about extraordinary strict regulations in the area of fire safety. So, many high, non-traditional or specific constructions originate, e.g. nuclear power plants due to permanently higher demand for transport linkage and many tunnels have originated between European countries as a result. Unfortunately, in this relation the threat of terrorist attacks increases and unexpected natural disasters which also threaten the stability of the mentioned constructions. The objective of the article is to familiarize readers with the results of research concerning the improvement of the resistance of the concrete to high temperatures originated during fire instances.

Development and Study of the Possibilities to Use Natural Materials for Thermal-Insulation Systems of ETICS

Thermal insulation systems of ETICS are now mostly solved in the building industry, whether in terms of insulating the structures, choices of materials and subsequent recycling after the end of their life period. From the environmental point of view and also in the perspective of sustainable development, it is essential to look for other suitable material bases which relate only to easily renewable sources of raw materials or to industrial wastes which have long been available in sufficient quantity and quality. It is important that production of the insulation systems is energetically efficient modest in terms of manufacturing facilities. The aim of this paper is to verify the possibility of using natural insulation materials for thermal insulation systems ETICS. This paper describes the results of studies of key properties of insulations based on industrial hemp and flax and the results of computational simulations of the behavior of these insulations incorporated in the real systems ETICS.

Effect of Plasticizing Admixtures on the Development of Hydration Temperatures and the Properties of Cement Pastes

The hydration of cement is a very intricate process. A great amount of heat is generated during the reaction, which requires close monitoring especially in large concrete members. Modified cement pastes are simpler systems and can be easily used to observe the effect of plasticizing admixtures on the development of temperatures during cement hydration as well as its rheology and mechanical properties. Knowledge of the development of hydration temperatures can be of assistance in deliberate regulation of cement hydration and the generation of hydration heat. The paper describes what influence different amounts of different plasticizers have on the properties of cement pastes, with added focus on the development of their hydration temperatures, rheology and compressive strength.

Utilization of Inorganic Binders for the Mineralization of Natural Fibers

The issue of natural fibers used for the production of materials with thermal insulation properties is its high moisture sensitivity and susceptibility to biodedgradaci. Effective protection of these fibers may be for some applications so. Mineralization which involves the application of inorganic compounds / binder to the surface of natural fibers. The paper focuses primarily on ways of implementing the mineralization using inorganic binders, and then changes the properties of natural fibers after application of various types of inorganic binders.

Development of Lightweight, Remediation Plasters and Study of their Moisture Behavior

One of the strategic goals of Europe 2020 is the reduction of greenhouse gas emissions by 20 % by 2020 compared to year 1990 and increasing energy efficiency by 20 %. Closely related to the revitalization of structures necessary for reasons reduction of their unsatisfactory energy consumption and then also the construction of new building structures with minimal energy requirements by using less energy demanding materials, if is it possible from easily renewable resources. Currently, the structures involved a high degree of total energy consumption in the European Union, about 40 %. Thermal insulating plasters with using lightweight aggregate based on recycled glass are the appropriate remediation materials for the rehabilitation of existing buildings, or even for thermal insulation of new structures. In view of the fact that historic buildings are often exposed to dampness and moisture, it is necessary for these redevelopment plasters also tackle studios moisture transport. The paper describes the results of the development of new insulating plasters that would have been reflected particularly in the rehabilitation of historic buildings and problematic details of building structures.

Determination of Thermal Conductivity on Lightweight Concretes

A range of testing methods were used to study the potential structural changes as a result of the effects of high temperatures on lightweight types of concrete developed above all for fire resistant structures. One such test for monitoring changes in concrete structures is the non-stationary determination of the coefficient of thermal conductivity using the hot wire method. The matrix structure progressively collapses as a result of the effects of high temperatures on the concrete structure ́s surface because erosion takes place of the matrix and aggregate porous structures. The degradation of the porosity of the concrete results in the deterioration of its thermal insulating properties. This paper assesses the dependence of the thermal conductivity coefficient of lightweight concretes on temperature and determines the potential occurrence of structural changes in the lightweight concrete matrix. The results were verified using other methods to determine the concrete ́s resistance to thermal load.

The Development of Lightweight Thermal Insulation Plasters and Experimental Analysis of their Moisture Behavior

The development of lightweight thermal insulation plasters containing alternative binders as a partial cement substitute opens the possibilities of using new, eco-friendly materials in civil engineering. The substitution of cement significantly reduces the energy consumption these materials’ manufacturing. In addition, they contribute to the overall energy performance of buildings, which represents another environmental benefit. Concerning the negative effect moisture has on the thermal insulation properties of plasters, the investigation focused on the influence of various hydrophobic agents on the hygrothermal behaviour of the newly developed porous materials. The goal of the research was to develop eco-friendly thermal insulation and rehabilitation silicate materials and to analyse their moisture transport.

Simulation and Measurement of Hygrothermal Behaviour of Newly Developed Plasters

Recently, there has been increased interest in the rehabilitation of existing buildings especially in order to improve their energy performance. Thermal insulation brings not only savings in the cost of heating or cooling but also contributes to the reduction of harmful emissions such as carbon dioxide, sulphur dioxide or nitrogen dioxide. However, the thermal insulation of historical buildings or buildings listed as cultural heritage brings some problems due to architectural features. It is therefore necessary to choose an alternative whether it is the use of an internal thermal insulation system or to repair and rehabilitate the existing plaster with materials compatible with the original ones. The newly developed thermal insulation plasters based on silicate and using lightweight aggregate and natural fibres are optimum materials for the thermal insulation of both existing and newly constructed buildings. The paper describes the results of research focused on the examination of the behaviour of thermal insulation plaster mainly in terms of heat and moisture transport. Using a computational programme, this behaviour was simulated for a chosen detail of a real building in the vicinity of a window jamb.