Advanced Materials Research Vol. 1020

Abstract: A development of fiber-cement composites is often focused on cost-effective and environmentally friendly materials (so-called green materials). Production of this material should produce less waste and it also should use less energy and less natural sources. There are numerous approaches to the development of green composites. One of the possible ways is a utilization of fly ashes instead of the cement part of composite. The paper discusses a development of green cementitious composite which incorporated fly ash materials produced in the Moravian-Silesian region as a partial replacement of the cement part of the composite.

Abstract: Titanium is most likely to play more important role in future civil applications. Its excellent properties such as: low density, high mechanical strength and good corrosion resistance give it some advantages and open the way for new applications both in modern technology and civil engineering. In many ways (e.g. specific strength, corrosion resistance) titanium, especially its alloys outstrip typical structural materials such as steel and aluminium alloys. The article discusses properties of titanium and its alloys, which are especially important in civil engineering applications due to their properties: low density, resistance to sea water and salty atmospheres of seashores, low coefficient of thermal expansion and excellent aesthetic qualities. Although the use of titanium in civil application is still limited it is expected that a demand for titanium building materials will steadily grow in the future. The characteristic titanium applications in the worldwide civil engineering are presented. It is highlighted that despite high cost of titanium relative to other materials, over a long span of 20 or more years titanium tends to be cheaper in terms of life-cycle costs. Furthermore, the article investigates the difficulties and opportunities associated with shaping titanium sheets. In the paper, some technological problems (e.g. low drawability, high susceptibility to galling and high spring-back) occurring in the sheet-titanium forming processes are discussed.

Abstract: Civil engineering uses steel as one of the basic structural materials. Sheets play an important role among the steel products. Although steel sheets are relatively cheap and have good mechanical and technological properties, low resistance against corrosion poses a fundamental weakness. A solution to this problem is the use of galvanised or organic-coated steel sheets. Galvanising can be carried out by hot dipping (single structural parts) or continuous galvanising: electrolytic and hot-dip galvanising (sheets and strips or long products, such as: wires or pipes).In the paper steel sheets used in the civil engineering as structural parts or wall and roof cladding are discussed. A special attention is paid to corrosion resistance of the steel sheets. Some results of corrosion tests is presented. The tests were aimed at determination the corrosion resistance of hot-dip and electrolytic galvanised sheets. The influence of the galvanising technology and the relationship between the degree of material deformation and susceptibility to corrosion are given. Coating thickness and kind of the applied galvanising technology is pointed as the key factors affecting the corrosion resistance of galvanised sheets. It is highlighted that during the forming process of galvanised sheets (bending, sheet-metal forming) the zinc coating deforms more than the steel base, so its thickness decreases, and therefore the corrosion resistance of the final product decreases, too.

Abstract: Optical parameters become to the features that are currently taken into account more frequently. There are various reasons of dealing with those parameters. Some of them are due to thermal calculation purposes while the other one are trying to consider low-emissivity functions of various innovative building materials. The paper is focused on spectral emissivity analysis of roof membranes and vapor barriers especially that are applied in sloped roofs and walls with air ventilated cavity. The spectral emissivity in the longwave radiation region was assessed by laboratory method of an infrared spectroscopy. The results present courses of spectral nature as well as its transformation into weighted values. As a result the final comparison demonstrates facts of aiming to point out the possibility of receiving any benefit for thermal aspects purpose.

Abstract: The paper evaluated thermo-technical characteristics of the experimental walls, consisting of five different tracks in three different color surfaces at different base material. The hygrothermal behavior of the structures and layers is monitored year-round. The computational model of the laboratory room and tested samples is compiled and debugged on the basis of experimental measurements. The dynamic simulations of temperature and humidity parameters were realized.

Abstract: This paper presents results of exploration related to C2 and C6 crushed-stone-and-sand ready mixtures strengthened with limestone powder used in road pavement layers. Limestone powder is an industrial waste, which in Ararat region is in big volumes. The samples were taken composed of different fractions of crushed-stone and two types of sand produced from crushed basalt and crushed gravel, and were tested. The composition of ready mixtures meets the requirements of corresponding standard on grain size. To these mixtures limestone powder was added of the percentage range 0-30% of the mixture mass. The main purposes of experimental exploration were to determine the influence of different percentages of limestone powder on compression strength of crushed-stone-and-sand ready mixtures and optimal content of powder. The change of the influence grade was studied by applying different types of sands. Three cylindrical samples were made for each percentage of limestone powder according to a standard method. Compressive strengths of samples have been determined. It was concluded, that the applying limestone powder in C2 and C6 ready mixtures contributes to the cohesion of stone grains as well as to obtaining high indicators of compaction in road pavement layers. The received results allow to arrive to a conclusion that applying limestone powder according to the optimal range distinctly increases the strength characteristics of crushed-stone-sand ready mixtures which in tur contributes the effective implementation of the compacting process. Especially the influence grade is considerable in C6 ready mixtures containing a large amount of crushed stone, as well as in mixtures using sands with smaller fineness modulus.

Abstract: Carbonation of the concrete is a process influencing acceleration of the aging of concrete during the time, at reinforced concrete structures it is usually accompanied with corrosion of the reinforcement and disturbances of the covering layer of the concrete. Its consequence is decrease of the static reliability of the reinforced concrete building structures. Carbonation of the construction from common concrete and lightened concrete causes just in the CR damage worth billions of Czech Crowns every year. The paper refers about seriousness of the current technical state of reinforced concrete structures and influence of the most important factors on the course of their degradation caused by carbonation and specifies principles for designing new reinforced concrete constructions.

Abstract: Chain of the life cycle of construction expanded polystyrene (production – construction application – liquidation after the end of the life cycle) is connected with significant energy consumption, consumption of oil, and production of considerable volume of construction and demolition waste. A sustained effort has been applied to increase effectiveness and to reduce the ecology waste from this process. Tools of this effort are the market mechanisms and legislation in the area of environmental issues and also the societal changes. Their consequences are especially the changes in structure of polystyrene producers and their production technologies, changes in composition of polystyrene and modification of procedures for handling the construction and demolition waste.

Abstract: As the floods have become more and more common phenomenon extend of damage on buildings has been increasing too. The wooden parts and constructions of buildings or the construction elements based on wood suffer the most serious consequences. Besides the traditional wooden constructions the modern constructions are more and more common in which wood is often accompanied and modified with other materials. Their behaviour might significantly differ from traditional wooden elements when flooded. This contribution focuses on analyses of the links having an influence on the extend and character of disruption of wooden structures and elements based on wood in buildings by influence of floodwater and its contaminants.