Papers by Keyword: Complex Modulus

Abstract: Road construction is now a priority in the economic and social development policy of a country. The increased need to improve the infrastructure system and to counter the deficit in certain quarry gravels and non-renewable resources while saving increasingly expensive road investments, makes recourse to the use of abundant and inexpensive materials in order to reduce the use of non-renewable natural materials. The objective of this research is to predict the viscoelastic behavior of asphalt mixtures incorporating high Reclaimed Asphalt Pavement (RAP) content, allowing to reduce the consumption of new aggregates and bituminous binders, and other additives such as dune sand and lime. A new formula containing 3,7% of 35/50 penetration grade virgin bitumen, 40% of Reclaimed Asphalt, 10% of dune sand, and 1% of hydrate lime was tested and compared to the conventional formula containing 5,3% of the same virgin bitumen. To evaluate the impact of dune sand and lime addition on the mechanical behavior of bituminous mixtures containing high rates of RAP, complex modulus tests were conducted on the studied mixtures, at different temperatures and frequencies, using a two-point bending device that was developed at the National School of Engineers of Tunis. Their viscoelastic properties were determined using a Generalized Maxwell model which was calibrated by 2S2P1D model. The paper describes a three-dimensional Finite Element (FE) model developed using ABAQUS software, that is used to simulate 2-point bending tests on trapezoidal samples of the studied mixtures to determine their complex modulus and accurately predict their mechanical behavior under traffic loading at ranges of temperatures and frequencies that are not experimentally accessible. To validate the FE model, determined viscoelastic properties have then been introduced into through the Prony series and its outputs were validated by experimental measurements. Both experimental and numerical results show that the use of RAP, dune sand and lime greatly improves the rigidity of the mix at high temperatures. A suggested continuation of this work would be an investigation of the rutting resistance.

Abstract: The deformational properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The Two-point Bending Test was used for determination of deformational characteristics of asphalt mixtures on Department of Construction Management in Žilina. The results are evaluated with the KATEMS assessment software. The long-term research leads to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component, recycling materials,...) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures, there are viscoelastic materials in construction of pavement.

Abstract: The creep behaviors of silicate-grouted sandy soil were investigated. A series of haversine creep tests with three frequencies (0.01 Hz, 0.05 Hz, and 0.1 Hz) were carried out to evaluate the dynamic properties (complex modulus and phase angle) of materials at low stress level. The stress-strain relationship for the sinusoidal test was plotted as an elliptical hysteretic loop. The complex modulus |G*(ω)| and the phase angle δ were determined from the hysteretic loop at a given frequency ω. While the complex modulus |G*(ω)| of the tested material increased, the complex compliance |J*(ω)| and the phase angle δ decreased with frequency ω within the tested frequency range.

Abstract: The deformational properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The Two-point Bending Test was used for determination of deformational characteristics of asphalt mixtures on Department of Construction Management in Zilina. The results are evaluated with the KATEMS assessment software. The long-term research lead to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures.

Abstract: on the analysis of the ageing kinetics model, ageing kinetics equation has been established on the basis of complex modulus. Rheological properties test have been carried out on SBS modified asphalt and base asphalt. The results demonstrate that when asphalt material in ageing process, the hypothesis that complex modulus is inversely proportional to the concentration of reactant assumptions of ageing reaction is established, on the basis of which, ageing kinetics constant has been obtained. Ageing kinetics equation has been validated by using measured data, it shows that, SBS modified asphalt owns higher reaction activation energy, a good anti-ageing property as well, that the measured data can keep accordance with calculated data, which demonstrates ageing kinetics equation is established reasonably on the basis of complex modulus. The equation can well describe rheological state changes of asphalt in ageing process.

Abstract: A list of monographs on internal friction, anelasticity, ultrasonic attenuation, relaxation phenomena in solids, and mechanical spectroscopy published in Soviet Union, Russia, and Ukraine is provided. A complete list of proceedings from international and Russian conferences is also given. This work is a valuable supplement to the Mechanical Spectroscopy - Suggested Reading Series.

Abstract: Mechanical spectroscopy and relaxation phenomena in solids are briefly discussed from the viewpoint of generalized susceptibility and linear response theory. Comparison of mechanical spectroscopy with other spectroscopic techniques is provided in the endeavour to formulate a multidisciplinary approach to selected relaxation phenomena in solids.