Browse

Anthropogenic pollution originating e.g. from waste landfills can migrate into the ground and significantly change its properties. Moreover, the interaction between soil and pollutants may change soil behavior as well as cause geotechnical problems. The aim of the study was the assessment of the impact caused by inorganic contaminants on consistency limits (plastic limit and liquid limit) of fine-grained soils. Laboratory tests were carried out on bentonite, kaolin and clay using KCl, MgCl2 and NaCl solutions. The...

Silica fume is a waste product created in the production process of metallic silicon, ferrosilicon and other silicon alloys in the electric arc furnace with or without heat recuperation of flue gasses. Microsilica as a waste hazardous to the environment after years of studies in laboratories and science institutes found its use in civil engineering. The utilization of silica fumes in civil engineering is mostly visible in the technology of high performance concretes (HPC). The examination of imposed thermal stress...

The purpose of this work was to investigate the possibility of wood preservation by its modification with different substances through the penetration method and to study the impact of the process on some operational properties of the wood material. The experiments were conducted with poplar wood (samples 10x1x1 cm), which has low density with well-developed capillary system, good absorption capacity and belongs to low operational capacities tree species. Alkaline activated hydrolysis lignin (AAHL), Cu2S and Malei...

Thermal insulating materials were obtained from diatomite and with burnable reinforcing additives, modified by synthetic and natural polymers. As burnable additives used rice husk, reinforcing additive is a basalt fiber, modifying polymer is polyvinyl alcohol and starch. Thermal insulating material obtained by mixing dry water mixtures at various ratios of components followed by drying and calcining at a temperature of 750 C. Parameters were determined linear shrinkage, density, compressive strength, the bending s...

In the latest decades, wooden structures have known a significant revival in the context of sustainability challenges, considering the low-embedded energy, low carbon impact of this renewable resource. The employment of modern wood structures presents many economical advantages as well, from the availability and the low-cost of the material, to the ease of processing and construction. An important aspect is the energy-efficiency of the system in exploitation, when we consider life-cycle assessments. Light-frame co...

The increased requirements to the strength of products from glued wood, in particular to plywood are imposed at the modern wood processing factories. The data on the development of high-strength plywood materials with the use of new intensive technologies are presented in the article. For creation of high-strength plywood polarization is used in the course of production of plywood. Polarization was carried out by means of fixed electric field. It is revealed that process of polarization exerts positive impact on a...

Multi Storied structures are used worldwide and have outstanding advantages in the use of composite materials in structural application. This study heads to an experimental study to reproduce the behavior on a composite joint configuration. Due to the lack of knowledge, during the last few years a lot of studies are based on the semi-rigid composite joints that can provide useful data about the behavior and the resistance of these connections. A number of two tests were performed to obtain a better development of ...

This paper describes an experimental analysis of damaged concrete corbel strengthened by gluing carbon fibre composite fabrics. The purpose of the investigation is to study all changes in behaviour and then their contribution to a better understanding of reinforced concrete corbel. Five reinforced concrete corbels are tested under tree-points bending to failure. Four of them are damaged at different load level up to 80% before strengthening. Test results show that strengthened corbel specimens using glue given an ...

One of the directions of rational use of energy resources in the field of drying of wood is the use of the managed heat pumps having the considerable potential for reduction of primary energy consumption when drying. Heat pumps can be used in combination with traditional fuel or electricity as an additional power source, or to act as the independent generator of heat and at the same time as draining device. The advantage of heat pumps is lower energy consumption for each unit of remote moisture, more exact managem...

The main theme of this article is a problem of storing underground utilities in different types of country. Supply services must meet dissimilar requirements for placing in rural or in the urban zone and respect all limits, which are binding in the known area. Technical security of urban settlement is a significant part of today's modern society, as is the flawless and reliable operation of water, energy and telecommunications networks. They all are a commonplace in each urbanized land and have an important impact...

This paper presents a study of performance evaluation of some fluid cement-based mortars containing mineral admixtures used as structural bonding material for fixing reinforcing steel bars in hardened concrete. The paper includes the developing of performance anchoring mortar for post-installed rebars based on ordinary blended cements. A series of standardized tests were performed within the experimental setup with the objective of assessing the performance of the mortars in terms of fluidity, cohesiveness and ear...

Current research directions in the field of both architecture and constructions are aimed towards satisfying the userпїЅs need in an ever-growing context that is struggling to drastically reduce energy consumption related to buildings. When designing housing units, that are always changing and evolving, it is imperative to consider developing a building envelope which seamlessly adapts to its surrounding climate conditions, so that exploiting and maintenance costs can be reduced according to the userпїЅs financial...

The article deals with the types of facility management approaches to the management and maintenance of utilities. It addresses the basic kinds of management and maintenance of these buildings in relation to the valid legal regulations of the Czech Republic, and it also discusses the need to solve these problems mainly because of the wear of buildings due to time, mechanical damage and weather conditions. Neglect of timely maintenance and repairs reduces the utility value of the building, which is contrary to the ...

Development of high strength concrete has been continuous over the years, its production becoming available at competitive prices to the construction industry, thus moving away from being a novelty product. Although high-strength concrete properties have been widely studied for nearly 100 years, currently available design standards for concrete structures contain stipulations based on research conducted on concrete with lower grades than those available today. The modulus of elasticity is a very important mechanic...

The paper presents a system monitoring operational safety of structures used in civil engineering. The system is based on the fibre Bragg grating (FBG) sensors or sensors using the optical time domain reflectometry (OTDR) technology. The essence of the solution is to introduce FBG sensors into the structure to make them act as its пїЅnervous systemпїЅ. The system may be implemented in existing civil engineering structures made of steel, concrete, reinforced concrete, as well as in shells and new structures at the ...

Modern prefabricated buildings, constructed according to the innovative Polytech technology are to be energy-saving and enable quick completion of the investment project. The new construction method uses load-bearing and, at the same time insulating, elements in the form of prefabricated panels made from the modified Polytech mortar. However, until today, the detailed data regarding the strength and deformability of important Polytech elements have not been verified. The new Polytech system has not been investigat...

The paper presents a system for monitoring of operational safety of ferromagnetic structures used in civil engineering, machine construction and power engineering. The system is based on sensors of the residual magnetic field (RMFM) distribution. A change in values of individual components of the residual magnetic field informs in advance about the appearance of areas with a raised level of stresses or stress concentration zones and identifies micro cracks. The paper presents numerous examples of identification of...

The recent demands regarding energy efficiency of buildings across the European Union, namely the nZEB concept, impose among other improvements, the thermal behavior optimization of building components that define the building envelope. In order to achieve the imposed nZEB criteria, conventional thermal insulations with increased thickness have to be used, which is inconvenient in several cases. The paper presents an alternative solution, given by Nano insulation materials, such as aerogel and vacuum insulation pa...

The paper refers to an experimental program aimed at evaluating the characteristics of masonry, with the objective of developing an innovative system for masonry, destined to be used for facades and envelopes. The purpose was to develop new masonry elements with good performance at thermal transmittance and good behavior at noise, fire and durability. Technical and economic feasibility of the masonry prototype systems was validated by experimental tests, according to European standards. The strategy for the develo...

The goal of this article is to present the problem of sustainable, self-sufficient and off-the-grid buildings in cold climates. Living off-the-grid is a part of the drive for sustainable living, in accordance with the principles of sustainable development. Buildings that are self-sufficient and which are not a part of the traditional power generation infrastructure have, on average, a much smaller environmental footprint and produce much less carbon dioxide, relying on renewable energy sources and environmentally ...

In last years, recycling has become a strategic factor in global politics, a vital component and a cost factor for economic development and the progress of society as a whole, generating a number of major global concerns. Exceeding twice the sum of all materials used in construction, annual concrete consumption around the world amounts to approximately 10 trillion tones being by far the most used building material and the partial or total replacement of a component of its mass with recyclable waste has a major pos...

Cement manufacturing has been always ranked in the list of the main sources of carbon emissions among industrial activities. Almost 5-7% of global CO2 emissions are caused by cement plants, while about 900 kg CO2 is emitted to the atmosphere for producing one ton of cement. On this account, there is laid pressure to reduce cement consumption by the use of alternative binders. In this paper, we would like to show that wheat straw ash can be used for the fabrication of construction composites with lower cement conte...

The handling and disposal of voluminous sludge produced from water treatment plants poses difficulty to environmental scientist and engineers. In fact, its environmental friendly management and disposal is challenging task and requires careful consideration. In this study, sewage sludge ashes were examined as potentially supplementary cementitious materials. The raw sewage sludge was provided by two different municipal waste water treatment plants, coming from Poland and Greece respectively. The calcination of pre...

Architectural restoration of historical buildings represents a very up-to-date topic of interest for the whole scientific community, architects, civil engineers and researchers. High performance and also aesthetical composite materials are continuously developed in order to fulfill the strict requirements of this sensitive area. Increased durability, superior mechanical characteristics, crack control for early cracking prevention and also smooth surface after removing of the mould / formwork represent a sum of pro...

The basic contractual instrument among all involved parties of construction projects in the Czech Republic is a contract for work according to the Civil Code of the Collection of Law of the Czech Republic. The contract is further supplemented by provisions based on long-term business experience and needs of contractual partners. An essential part is the type of price, its amount and the method of determining or adjusting the price. For green constructions in general and green buildings in particular it is customar...

This contribution deals with the verification of airflow in the real air gap of an insulated roof deck with a pitched roof. The designed construction of the roof meets the thermal technical requirements for an energy passive house. The aim of this contribution is a comparison of experimentally measured values with values obtained through a computer simulation. Double skin ventilated roof structures operate on the principle of the removal of moisture vapour by the flow of air. The flow of air is generated by the di...

The paper describes the possible applications of expanded polystyrene (EPS) granulate derived from recycling for the production of prefabricated building units. Test results of a new material called Polytech and its application in the construction industry are presented. Polytech construction system is based on prefabricated large-panel units. An important advantage of the new material is the volume representation of EPS granulate, which reaches up to 60%. So far пїЅ in order to keep the proper strength of the man...

The use of weak local soil as well as the recycling of existing worn-out structures such as old road pavements using micro particle road binders are a beneficial ecological solutions. Parameters of the soil stabilized with binders significantly affect the load bearing capacity and durability of the built structures. Mechanical parameters of the soil are therefore needed in the analysis and design of soil structures. Determination of the exact value of these parameters in indirect tensile test is related to the nee...

There are numerous technological and material solution in the building sector. As more and more emphasis is laid on the protection of nature in the contemporary world, new pro-ecological solutions are devised all the time. One of the most recent trends in the technological development of civil engineering is green technology. In the construction industry, it primarily means solutions with an aim of attaining efficient management of energy and natural resources, from production of building materials, through design...

The aim of this study is to explore the possibility of recycling waste materials of brick aggregates (BA) and demolition concrete aggregates (DCA) in the self-compacting concrete (SCC), by studying these fresh and hardened properties. A reference mixture based on natural aggregates (NASCC) and six mixtures incorporating recycled brick aggregates (BASCC), recycled demolition concrete aggregate (DCASCC) and combination of recycled brick and demolition concrete aggregates (BDASCC), as replacement of natural aggregate...

The building sector is interested in developing new types of structures capable to resist seismic loading. There is introduced a new structural detailing of mix steel-concrete structures. The innovative design consists in use of the precast concrete slabs and steel frames, assembled by post-tensioning, of the prestressing procedure for the steel members and also a different column-beam connections having resilient characteristics. Each of the listed features is also special. The prestressing reinforcement is locat...

This contribution results from the experiments conducted in the experimental gallery in the limestone pit. The gallery consists of three horizontal parts, two of them are parallel. The premises of the experimental galleries are used for testing and research in the area of explosion prevention. The partition masonry walls were built inside the gallery and they were subjected to the blast load induced by air-gas mixture. The paper introduces the principles for determining the dynamic load and for its simplification,...

The calculated energy efficiency and specified physical properties of building materials may change significantly during the initial years of a buildingпїЅs operation under real climatic conditions. Five small test buildings with different wall assemblies were built in Riga, Latvia to compare different building construction characteristics under Latvian climate conditions. The heating energy consumption, thermal transmittance, air relative humidity and other important energy efficiency and environmental parameters...

This contribution provides a prefabricated elements constructive system, which guarantees definite features and energy saving, with integrated energy performances and structural behaviors. First, we considered the requirement framework, identifying which were the indispensable energy, structural, environmental and product performances. These choices were then examined through UNI PdR13, which is today the benchmark for Sustainability in Italy. Secondly, the market scenario of this system was defined, identifying t...

The primary aim of earthquake resistant design is to prevent building collapse during the seismic event, but severe earthquakes have a low probability of occurrence during the life time of the structure, therefore in contrast to traditional structural design in earthquake design, structures are permitted to work in post-elastic domain under seismic load. It would require a large lateral stiffness of the structure and an expensive resisting system to design the building to have an elastic response. Because of these...

Sustainable design attempts to be perceptive to the environmental impact of the building project at each construction stage by evaluating the site, the embodied energy of the selected materials, as well as the proper construction techniques, adjusted to the local conditions. Moreover, physical hazards (flammability, corrosion) and/ or health hazards (toxicity, irritations) of the materials are especially important not only for the construction workers, building owners and occupants, but also for the environment, c...

The presented paper deals with the design and examination of steel towers of electrical transmission lines with circular or polygonal cross section. Structures of this kind are a safe and reliable option when selecting the appropriate structural solution, but nevertheless often remain omitted due to difficulties with design methodology. The cross sections of conical towers are in majority of cases categorized as class 4 sections. Being classified as such, they are in certain loading situations considered as shell ...

The article discusses the need to introduce energy management of municipally-owned buildings provided by the concept of Smart Cities. Cities use many buildings. These buildings also have a different nature of use, such as offices, schools, social care homes, etc. All these buildings consume energy that needs to be monitored and regulated. Energy management needs a large amount of relevant data on these buildings together in one comprehensive system. When planning building revitalization, it is necessary to have su...

This article is referring to a short study regarding the energy efficiency status in retail industry in Romania, in particular an analysis of the big sizes commercial buildings in this matter. It contains data which will allow us to compare an existing building with the industry norms in terms of the energy consumption and energy costs. Additionally, there are some recommendations provided to be taken care of in the near future for controlling energy better, using energy in a more efficient way and reducing avoida...

Starting with the year 2020, all new buildings in the European Union, must meet the requirements imposed by laws on energy efficiency. Romania is an EU member country, accordingly must also respect these provisions. In the present study, we identified new hybrid elements for construction of closing/partitioning, energy efficient. These are the result of associations of construction materials with similar properties, having a very low thermal conductivity. The main materials used to make hybrid structures, energy e...

This article is the continuation of the paper published at the conference SGEM in 2016. European product standards generally do not specify the qualitative requirements for individual product characteristics. EN 14695:2010, which deals with the waterproofing of concrete bridge decks, is not an exception. The national standard CSN 736242:2010 sets quality requirements for bitumen sheets. The type of the modification of bitumen coating is not considered in quality requirements of this standard - the mass modified by...

"Sustainability" is a key term, not only when we talk about пїЅeco buildingsпїЅ, but also when we talk about lifestyle and development in general. Widespread awareness of climate change, pollution, depletion of natural resources together with huge amount of technical opportunities on global market have triggered professional demands for architects with advanced skills in design. Present task is not only to create new technical variations, but to re-think architectural design process to find a really complex evalua...

Nowadays concrete is the worldпїЅs most widely used building material. A decisive constituent is cement, which causes in production nearly 10% of the worldпїЅs CO2 emissions. Ultra High Performance Concrete (UHPC), a new high-tech concrete with an outstanding compressive strength of 4 to 6 times the strength of standard concrete (NSC), is the most advanced building material in reinforced concrete construction and increasingly used in different countries all over the world. Due to its high compressive strength, bui...

New innovative smart adaptive materials and optical measurement system can be implemented in civil engineering. Smart materials can be especially used in cased where fast and efficient way of reduced vibrations, weight and deflections is required. The essence of the solution is to introduce FBG sensors into the structure to make them act as its пїЅnervous systemпїЅ. The system may be implemented in existing civil engineering structures made of steel, concrete, reinforced concrete, as well as in shells and new stru...

The global level of urbanization is growing. Some estimates indicate that till 2030 the degree of urbanization will reach 83% in economically developed countries. In this context, large urban areas are already facing with problems due to water and air pollution, noise pollution, forming "heat islandsпїЅ, energy consumption, overload of rainwater collection systems and human health degradation. In this paper are presented the benefits of green roofs and the contribution they play in solving problems in urban areas....

The correct design of the construction equipment objects and their usage plays an important role in the overall efficiency of the construction with regard to the execution time, the resulting price, performance of workers on the construction site and use of deployment mechanisms. During the construction is the possibility of using alternative sources in the design of construction equipment, which may contribute to the overall efficiency of the construction. The article gives an example how to proposal a suitable t...

This study of an alloyed steel with Cr, Mo which has an important content of aluminum (0.9,пїЅ1.2)%, unconventional treated in magnetic field, is attractive because of the increasing of the durability and the wear resistance along with the improvement of the corrosion resistance. Thermo-magnetic treatments applied before the thermo-chemical treatment has consequences such as the improvement of the mechanical properties of this material. The micro-hardness of the superficial layers has been increased after the unco...

Metakaoline is a relatively new pozzolanic additive, obtained by calcination of kaolin clay at relatively low temperatures. Themselves pozzolanic additives are known for a very long time. Currently, there is interest to pozzolanic materials again, because their usage allows reducing the total environmental impact and cost of cement. The influence of metakaoline on hydration and hardening of cement was studied. The usage of metakaoline as the additive to cement composition increases the strength of cement stone. Be...

One of the priority issues of humankind is global warming, due in particular to greenhouse gas emissions (GHG), the diminishing of which is a global priority. The use of heat pump systems over conventional boiler systems to produce heat for heating or cooling (boilers, chillers) has a significant impact in terms of GHG reduction. The GHG reduction process is characterized in particular by the COP of the heat pump systems and the greenhouse gas emission intensity resulting from the electricity generation process. F...

The buildings energy performance is becoming increasingly important, because of environmental restrictions connected with CO2 emission and rising costs of fuel end energy. Respecting sustainability issues, design of buildings with improved thermal properties and optimum energy performance is preferred, whereas specific attention has to be paid not only to the design of building envelopes, but also to the thermal insulation of buildings subsoil. To obtain buildings with high thermal resistance and sufficient therma...