Nowe zasoby w kolekcji Konferencje Krynickie - Referaty http://suw.biblos.pk.edu.pl/ Biblioteka Politechniki Krakowskiej lipinska@biblos.pk.edu.pl 60 <![CDATA[Characteristics of the complex modulus of recycled cold mix with foamed bitumen and recycled concrete aggregate]]> Sat, 15 Jun 2019 11:46:38 +0200 Buczyński, Przemysław; Iwański, Marek
rodzaj: referat opublikowany w czasopiśmie
Abstrakt: This article presents research on recycled cold mix with foamed bitumen (MCAS) containing recycled concrete aggregate. The primary concept driving this research was to determine if recycled concrete aggregate (RC) could be used as a substitute for reclaimed asphalt pavement (RAP). Recycled concrete aggregate was used in the MCAS mix in amounts ranging from 20%, 60% and 80%. The reference mix was the MCAS mix containing 50% reclaimed asphalt pavement (RAP) and virgin aggregate. Identical 0/31.5-mm continuously graded dolomite virgin aggregate was used in all mixes. 2.5% foamed bitumen (FB) and 2.0% CEM I 42.5R Portland cement (PC) were used to increase the cohesion of the mineral mix. Foamed bitumen was produced from 50/70 penetration paving bitumen. The behaviour of the recycled base course was tested in the range of cyclic sinusoidal strain with amplitude εo = 25–50 με. The tests were carried out in the (-7°C, 5°C, 13°C, 25°C, 40°C) temperature and (0.1 Hz, 0.3 Hz, 1 Hz, 3 Hz, 10 Hz, 20 Hz) loading time range. The complex modulus was tested in a direct tension-compression test on cylindrical samples (DTC-CY) in accordance with EN 12697-26. The results of the tests were used to assess the complex modulus (E*), phase angle (φ) and complex modulus components (E1) and (E2).Tests of the mixes indicate that recycled concrete aggregate can be used in recycled cold mixes in amounts of up to 80%. Increasing the amount of recycled concrete aggregate does not cause excessive stiffness of the recycled mix in comparison with the reference mix. The tests did not demonstrate a significant difference in terms of the phase angle (φ), which indicates a similar content of the viscous part and elastic part in the obtained complex modulus for the reference mix (RAP + MCAS) and the mix containing recycled concrete aggregate (RC + MCAS).]]>
<![CDATA[Assessment of Gilsonite and Trinidad Epuré natural asphalt-modified binders ability to relaxation at low temperature]]> Sat, 15 Jun 2019 10:42:57 +0200 Bilski, Marcin; Słowik, Mieczyslaw
rodzaj: referat opublikowany w czasopiśmie
Abstrakt: The paper presents the results of the tests conducted on asphalt binders modified with additives of natural Gilsonite and Trinidad Epuré asphalts, as well as the 20/30, 35/50 and 50/70 penetration grade bitumens by use of an original observation method of the relaxation phenomenon in low temperature. In the tests the authors used a ductilometer equipped with a dynamometer and a bath filled up with a liquid with the temperature of-16°C. Relaxation of the asphalt binder was observed in the period of 20 minutes in the conditions of constant deformation of the sample caused by its prior extension with the constant speed of 1 mm/min. The value of the normal stress occurring in the asphalt binder is calculated on the basis of the measured value of the normal (tensile) force. It has been noted that asphalt binders with higher penetration values are characterised by a better relaxation ability at low temperature, that is relaxation takes place faster and has higher values of sample stress reduction in the domain of time, at constant strain. With approximate penetration values (the maximum penetration difference at 25°C amounting to ±2 mm/10), modified binders comprising Gilsonite are characterised by better relaxation abilities in comparison to binders containing the Trinidad Epuré additive.]]>
<![CDATA[Geotechnical characteristics of unburnt colliery spoils after coal-recovery]]> Sat, 15 Jun 2019 09:56:08 +0200 Zydroń, Tymoteusz; Gruchot, Andrzej; Zawisza, Eugeniusz
rodzaj: referat opublikowany w czasopiśmie
Abstrakt: The aim of the study was to determine the geotechnical characteristics of the unburnt colliery spoils after coal-recovery from the dumping site of one of the mines of the Upper Silesian Coal Basin in Poland. Due to grain-size distribution of tested spoils their geotechnical properties were determined using medium-sized apparatuses. In order to verify the suitability of the studied spoils for the construction of hydraulic embankments, the seepage and stability calculations were conducted for models of hydraulic embankments including the effect of flood wave passage on stress conditions within the construction and their slope stability. The test results revealed, that the studied colliery spoils are characterized by favourable values of geotechnical parameters and they fulfil the requirements for soil materials used in the analysed type of constructions. The spoils are characterized by good compactibility, relatively low water permeability and average susceptibility to mechanical disintegration, which in the case of using this material for the construction of hydraulic embankments and using proper compaction technology, should reduce their susceptibility to weathering. The results of seepage and slope stability calculations for hydraulic embankments built of the studied spoils confirmed their suitability for that type of constructions, retaining the proper inclination of slopes, whereas the variant of embankment without sealing is safer from the stability viewpoint.]]>