Degradation of building materials in housing objects caused by influence of environment

Environment is one basic factors which influences lifetime of building structures. Most problems of the lifetime of housing objects are usually accessed by non-complex manner, because in the cases of reconstructions and modernisations is not paid adequate attention to elongation of the lifetime of building to be reconstructed. By the solution of this tasks it is necessary to take into account the extreme stress of constructional elements caused by aggressive environment which is determined by the microclimatic conditions of neat-house resulting to retrogradation of building materials and structural elements. This contribution deals with evaluation of the impact of aggressive environment to the lifetime of concrete and reinforced structures with accent on lifetime increase of buildings and relation to physiology of housing animals and requirements of human sanitation. This contribution deals with evaluation of aggressive environment influences on the lifetime of concrete and reinforced structures of housing object, after 30-35-year usage. This case study deals with 4-line cowshed T 174/3 localised in Liptovsky Ondrej (northern part of the Slovak Republic). For roof structure were used concrete plates SZD-10n-450, bedded on external walls and prefabricated bearers RZP-84-450 resp. RZP-83-600. Bearers are bedded on prefabricated concrete columns NZS-56. For the production of all prefabricated elements was used concrete B-20 and reinforcement steel J-10335. All prefabricated elements were manufactured in Plant of Engineering Prefabrication, Bratislava. Entire building was evaluated visually paying attention to scratches (direction of scratches), extreme deformations and to damages of concrete and reinforcement. Carbonation of concrete was determined through solution of alcohol and phenolphthalein. Concrete strength was determined by Schmidthammer (N-type) and by point durometer (Ciganek modification). Quality of reinforcement was determined through direct measuring after uncovering. For classification of cross-section of reinforced concrete elements was used a scale with six degrees: 1 - corrosion hits covering layer only, 2 - covering layer is strongly damaged, beginning of reinforcement corrosion, 3 - corrosion hits reinforcement in full measure, they are scratches in concrete, 4 - reinforcement is strongly hit by corrosion, covering layer is damaged through scratches, concrete is detached from reinforcement, 5 - reinforcement is considerably weaken, 6 - bearing elements do not fill supporting function. Reinforcement of roof plates was considerably damaged and carbonation of concrete was determined. Reinforced cross-section of concrete plates was classified through the degree 5 of above mentioned scale of damaging. There were identified two cases of prefabricated bearer damaging in the places of their supporting points - scratches direction was 45 degree. Reinforcement of bearers was not uncovered, damaging of cross-section was classified through degree 1. Covering layer of concrete columns were mechanically damaged to height of 1.5 m with partial carbonation of concrete. Corrosion of reinforcement of columns was classified by degree 2. From the results of observation and evaluation it is evident the influence of consistent aggressive environment of cowshed interior (carbon dioxide, vitriol acid and ammonia) to degradation of structural element properties. For the object observed within this study it is necessary to perform a large reconstruction. Prefabricated columns and bearers are appropriate for reconstruction, however roof plates must be built newly