Diploma thesis deals with adding R - material to the wearing asphalt courses, specifically to the SMA 11S. It has two parts – theoretical and practical. The theoretical part describes using R - material in the recycling of roads, different types of recycling and how is this problem handled in the Czech Republic, the practical part deals with the design of three kinds of asphalt mixtures with different added ratios of R – material, describing empirical and functional tests on the bitumen binder and the designed asphalt mixtures and the results of those tests.

M. Tech. (Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technology) / Modified asphalt concrete is one of the important construction materials for flexible pavements. The addition of polymers and natural hydrocarbon modifiers to enhance the properties of asphalt concrete over a wide temperature range in paving applications has been the common practice. Currently these modified asphalt mixtures are relatively expensive. However, recycled polymers and rubber added to asphalt have also shown similar results in improving the performance of road pavements. In this study, an attempt has been made to use low density polyethylene (LDPE) obtained from plastic waste and crumb rubber obtained from worn out vehicle tyres. The aim was to optimise the proportions of LDPE in the bitumen binder using the ‘wet process’ and crumb rubber aggregates in the hot mix asphalt (HMA) using the ‘dry process’. The Marshall method of bituminous mix design was carried out for varying percentages of LDPE namely 2%, 4%, 6%, 8% and 10% by weight of bitumen binder and 1%, 2%, 3%, 4% and 5% crumb rubber by volume of the mineral aggregates. The characteristics of bitumen modified with LDPE were evaluated. The modified asphalt mix was also evaluated to determine the different mix characteristics. The results from laboratory studies in terms of the rheological properties of the LDPE modified bitumen binder showed an increase in viscosity, softening point and stiffness of the binder. The optimum Marshall stability values for HMA mixtures containing 2% crumb rubber tyre and 4% LDPE were found to be 30% higher than the conventional asphalt concrete mix. The wheel tracking test done at 50ºC was 9.81mm rut depth showing a good rutting resistance of the optimized mixture compared to the conventional asphalt mixes. The Modified Lottman test gave a Tensile Strength Ratio value of 0.979 which indicates a low degree of moisture susceptibility of the modified asphalt mix. The above results showed improved properties of the asphalt mixture. The economic assessment done using the present worth of costs indicated a reduction in maintenance cost due to the extended service life of the modified asphalt pavement.

The diploma thesis deals with the production of warm mix asphalts, using the foam bitumen technology. The thesis is divided into theoretical and practical part. The theoretical part is focused on the basic division of roadway constructions, particularly on warm mix asphalts. The aim of the practical part was to find out whether the produced asphalt mixture retains its functional properties when the operating temperature is reduced. For this purpose, two asphalt mixtures of the ACO 11+ type at operating temperature of 150 °C and reduced operating temperature of 130 °C were made. Functional tests and empirical and functional tests were carried out on the produced asphalt mixtures and the extracted bitumen binders respectively. In the conclusion of the thesis, the results of the tests are mutually compared.

The diploma thesis is divided into theoretical and practical part. The theoretical part is mainly focused on methods for reducing the working temperature in the production of hot mix asphalt and the main reasons for this. Most attention is paid to the warm mix asphalt, mainly foam asphalt technology. In practical part are describes working procedures of individual tests on asphalt mixtures and recovered bitumen binders. The tests were performed on 3 types of ACO 11+, one was made with working temperature 160°C without foamed bitumen and the other two with foamed bitumen,one with working temperature 160°C and the second 140°C. Then were the results compared.

Diploma thesis deals with the topic of using recycled material in the production of asphalt mixtures. In the theoretical part the methods of recycling flexible pavement are described and as well as ways in which recycled material is added to asphalt mixtures produced by the stationary hot mix plant. The thesis also deals with the current state of recycled material use in the Czech Republic and the reasons for its possible greater use. The practical part of the thesis studies the effect of using the amount of 20% recycled material to asphalt mixtures of asphalt concrete for wearing course ACO11+, on selected functional properties of these mixtures. It is also investigates the influence of bitumen binder contained in the recycled material, on the final properties in manufactured asphalt mixtures. An integral part of this thesis is a description of all methods that were used during the processing of the practical part. In the end of this thesis there are some results of findings about adding recycled material into asphalt mixtures.

Diploma thesis deals with topic of using aramid (Kevlar) fibres in road engineering in asphalt mixtures. Theoretical part of thesis is describing characteristics of aramid fibres and their technical usage. Thesis deals with research and application of aramid fibres abroad and also in Czech Republic. Practical part deals with influence of aramid fibres, namely FORTA FI fibres in mixture with modified binder for wearing course. An integral part of this thesis is a description of all methods that were used during the processing of the practical part. In the end of the thesis there are outcomes of tests and theoretical research.