Słowa kluczowe

concrete |sawdust |construction |sawdust concrete |green building

Streszczenie

Sawdust concrete is a type of lightweight concrete in which some of the mineral aggregate is replaced by sawdust - a by-product of wood processing. It is not a new material, but its potential is not utilised to its full degree. Taking into account the most important advantages of sawdust concrete - lower density and greater thermal and acoustic insulation than ordinary concrete - it is worth to consider the possibilities of its usage in construction  wider than currently . In order to present the properties of sawdust concrete, the review of contemporary technical literature has been performed.

For the production of sawdust concretes mineralized sawdust from various types of trees, ordinary cements, mineral aggregates and water, are used. The usage of additives and admixtures is also allowed. The properties of the finished sawdust concrete are mainly influenced by the proportion of its components, especially the amount of fine aggregates replaced by sawdust. The construction products made of sawdust concrete are characterized by a low coefficient of thermal conductivity λ and soundproofing properties. In bending tests, a simply supported sawdust concrete beam behaves similar to a regular concrete beam, cracks first appear in the tension zone. Tensile strength, compressive strength and Young's modulus of sawdust concrete products depend on the proportion of components and the method of sawdust preparation before applying in the sawdust concrete-mix. Compared to ordinary concrete, the obtained values for sawdust concrete are lower, but partially fall within the ranges for the lower classes of ordinary concrete.

There are several possible applications of sawdust concrete in construction. One of the perspectives is to use it to build walls in buildings that require soundproofing between rooms, or to replace wood with it when renovating old buildings. However, further tests of sawdust concrete are needed in terms of the most favourable composition for its mechanical properties, and to define the standards according to which sawdust concrete elements should be produced.

Słowa kluczowe

wind |urban structures |comfort |heat loss

Streszczenie

The dynamic development of built-up areas observed in the last few decades resulted in strong environmental transformations, especially in terms of climate phenomena. One of the factors which significantly affects the climate and bioclimate of urban areas is wind. Wind can cause discomfort to pedestrians or heat loss in buildings, if the wind speed around buildings is too high. The paper presents two examples of research conducted by the author, related to the issues of wind flow in built-up areas, based on the numerical simulations. The numerical simulations become an increasingly frequently used tool to determine the wind climate. Simulation results provide designers with important information on the influence of the buildings and their layout on the local changes in airflow. They allow testing of alternative solutions and effectiveness of various remedial measures.

Słowa kluczowe

billboard |outdoor advertisements |building facades |visual pollution |destructive effect

Streszczenie

Polish cities are currently facing an issue of intrusive billboards obstructing the faacades of buildings. While the majority of articles on this subject focus on the negative impact this phenomenon, little attention is drawn to the destructive technical effects  the advertisements have on the facades. This article addresses phenomenon of visual pollution examins the  influence of based on the example of selected buildings located in Lublin’s City Centre. The article analyses the placement of advertising signs, and categorizes of most technical and social problems that it entails. The relation between the occurrence of outdoor advertising and the increase in anti-social behaviour in commercialised space, raised in the article, could be a very important topic for further research. The results of the conducted study reveal that the installation of advertising billboards irreversibly damages the facades of buildings, which is especially visible when the advertisements are removed. The article complements the study on outdoor advertising, drawing attention to one of its little-discussed, technical aspects. Consequently, it may serve as a starting point for further discussion on the subject.