Jan Broda

By Jan Broda

Part of the book: Polypropylene

By Jan Broda

Polypropylene fibres have been applied for reinforcement of cement mortars and concrete for many years. The fibres restrict crack propagation and positively affect several concrete parameters. To improve the adhesion of polypropylene to cement matrix, geometrically deformed or modified fibres are commonly used. Good results are obtained by application of fibrillated fibres with the net-like structure obtained from the polypropylene types. The fibrillated polypropylene fibres were produced. The fibres were chopped to specified lengths and used for the reinforcement of concrete and cement mortars. The parameters of fresh concrete and mechanical parameters of reinforced concrete and mortar were determined. It was stated that the fibres do not affect the compressive strength of the reinforced concrete and mortar. The beneficial effect of fibres on the compressive strength of concrete is revealed after freezing and thawing cycles. The fibres influence the bending strength of the mortars. For mortars reinforced with fibrillated fibres a significant increase in the bending strength is observed. The increase in the bending strength results from enhanced interfacial adhesion and mechanical anchoring, which results from opening of the network structure and splitting of fibrillated fibres.

Part of the book: High Performance Concrete Technology and Applications

By Jan Broda

Wool geotextiles were formed from the meandrically arranged thick ropes and used as erosion control products. The geotextiles were installed in the experimental sites to protect the endangered slopes and the bank of ditches. Additionally, as a reinforcement of the soil, loose wool fibres were applied. The progress of wool biodegradation on the slope was investigated. Changes in the outer appearance, mechanical parameters, molecular structure and fibre morphology were analysed. Moreover, the nitrogen content in the soil and the effect of compounds released into soil on the grass growth were studied. The measurements revealed that the biodegradation starts at the cleavage of disulphide bonds, followed by disruption of the peptide bonds. Degradation is initiated in the outer cuticle and is followed by the decomposition of the inner cortical cells. During biodegradation, the nitrogen-rich compounds are released. The compounds act as an effective fertiliser which supports the growth of grass and significantly accelerates the greening of the slope.

Part of the book: Environmental Chemistry and Recent Pollution Control Approaches

By Anna Salachna, Katarzyna Kobiela-Mendrek, Maria Kohut, Monika Rom and Jan Broda

The Silesian Beskids (Poland), the westernmost part of the Carpathian Mountains is an area with long pastoral tradition. For centuries sheep grazed in clearings located among forested ridges have been an integral part of the mountain landscape and pastoral customs have become essential elements of regional cultural heritage. In the chapter, the history and the current state of pastoralism in the Silesian Beskids are presented. The specific pastoral system developed in the region, based on annual migration of flocks between summer highland and winter lowland pastures is described. Local breeds and specific regional sheep products are depicted. Furthermore, the importance of pastoralism for the environment, landscape and plant biodiversity is analysed and efforts to recover sheep grazing in the mountains after a period of a deep recession caused by social and economic transitions connected with the collapse of the communist system are presented. The approach to restoration of pastoralism is illustrated using a case study of a pastoral centre which combines traditional sheep grazing with cheese production, education and several activities to promote pastoral tradition.

Part of the book: Sheep Farming