Deformation Parameters and Fatigue of the Recycled Asphalt Mixtures

The deformational properties of asphalt mixtures measured by dynamic methods and fatigue allow a design the road to suit the expected traffic load. Quality of mixtures is also expressed by the resistance to permanent deformation. Complex modulus of stiffness and fatigue can reliably characterize the proposed mixture of asphalt pavement. The complex modulus (E*) measurement of asphalt mixtures are carried out in laboratory of Department of Construction Management at University of Žilina by two-point bending test method on trapezoid-shaped samples. Today, the fatigue is verified on trapezoid-shaped samples and is assessed by proportional strain at 1 million cycles (ε6). The test equipment and software is used to evaluate fatigue and deformation characteristics

SIMULATION MODELS IN OPERATION OF ROAD TUNNEL

Prevádzkové stavy je možné simulovať na simulátore riadenia tunelov (SRT), ktorý má Žilinská univerzita k dispozícii v prevádzkovom stave od septembra 2013. Na simulátore môžu operátori overovať rôzne prevádzkové stavy a získať zručnosti, ktoré by sa mohli využívať pri ľubovoľnom prevádzkovom stave konkrétneho tunela a ktoré pri prevádzke konkrétneho tunela nie je možné v reálnom čase overiť.It is possible to simulate operating states on a Tunnel Traffic & Operation Simulator, which is available at the University of Žilina from September 2013. Operators can check different operating states and acquire skills that could be used at any operation state of the particular tunnel and which are not possible to obtain and verify in real time of the operation a particular tunnel

The Influence of Recycled Materials on Cold Mix with Foamed Bitumen Properties

The utilization of recycled materials is an important issue in the context of environmental protection. The large amounts of recycled material recovered from the demolition of asphalt road structures indicate the need to find new ways of utilizing them. In the case of road renovation projects, large amounts of recycled materials are, in most cases, recovered in the form of reclaimed asphalt pavement (RAP), reclaimed concrete (RC) and recycled aggregate (RA). To focus on the effects of the use of recovered materials (RAP, RC and RA), the same composition was used for all of the analyzed mixtures in terms of foamed bitumen (FB) and Portland cement (CEM) content. The scope of laboratory tests included the specification of the following parameters: the amount of air void content Vm, the determination of axial compression strength at +25 °C, indirect tensile strength (ITS) at +25 °C, water resistance, TSR, water and frost resistance, WRW+M stiffness modulus (IT-CY) at 13 °C, dynamic dynamicmodulus. The plan of the experiment assumed addition recycled material in quantities between 20% and 80% in increments of 20%. The obtained results indicate that both the type and quantity of recycled material significantly affect the properties of the cold-recycled mixture with foamed bitumen. Using reclaimed asphalt pavement and recycled cement concrete guarantees high levels of stiffness in the recycled mixture. Howeverin the case of recycled aggregate, the authors did not observe any visible changes in the dynamicdynamic modulus, irrespective of the loading conditions. It was also indicated that it is necessary to reduce the quantity of reclaimed asphalt pavement in the composition of the FB-RCM mix to maintain the required air void content

Simulation of emergency events with fire in virtual road tunnels

Road emergency events are very dangerous, especially if they happen in tunnels. If such an event occurs with the presence of fire, self-evacuation is the most important. From experience from catastrophic events in Alpine tunnels, people can only have a few minutes to rescue. It was also reason that a lot of changes in technology and safety tunnel equipment have been legislatively adopted. Then if we want to help rescue people, we need experienced tunnel operators, who know the principles of tunnel ventilation control with fire and smoke. This paper is about simulation of emergency events in virtual tunnel of Tunnel Traffic & Operation Simulator (Simulator) and about simulations of smoke stratification on the basis of Computer Fluid Dynamics (CFD) models

Composition Optimisation of Selected Waste Polymer-Modified Bitumen

Waste plastomer disposal is currently a major challenge facing modern economies. This article reports on a study and analysis regarding the implementation of plastomers into bitumen, with a special focus on the influence of mixing process factors. Two plastomers were selected for analysis, PP and PET, and two bitumen types, 20/30 and 70/100, were modified. Determination of the basic characteristics, such as penetration, softening temperature, cohesion energy, and Fraass temperature, was complemented with advanced multiple-stress creep recovery (MSCR) rheological testing. The entire experimental process followed the Plackett–Burman design. Rheological effects of modified bitumen were evaluated using the generalized Maxwell model. Microstructural analysis with epi-fluorescence microscopy showed the ability of plastomer-modified bitumen to obtain a fine-grained structure with a particle size of <10 μm. In addition, creep susceptibility (Jnr) was found to be statistically significantly dependent on the polymer type and particle size, rotational speed, and bitumen type. In turn, the particle dispersion structure in the bitumen matrix significantly depended on the rotational speed, plastomer particle size, and mixing temperature. Ultimately, the process of bitumen 70/100 modification was optimized. It was demonstrated, following the experimental design, that by using fine-grained PP for a temperature of 160 °C, rotational speed of about 6300 rpm and time of 105 min, it is possible to obtain modified bitumen with rheological properties very similar to those of modified bitumen PmB 45/80-55

Increase of road tunnels safety using Tunnel Traffic & Operation Simulator

Tunnels, constructions used to shorten transport routes and to improve road safety, are specific engineering structures where the safe operation is very important. Tunnel Traffic & Operation Simulator (Simulator) was created as a solution of research task focused on increasing safety in road tunnels within the framework of the project “Centre of Transport Research (CVD)” funded by European Regional Development Fund (ERDF). The Simulator is located on Faculty of Civil Engineering of the University of Žilina (Slovakia) and is adapted to control the tunnel in two operator’s mode which are functionally convertible. They can during the operation of the simulator control the tunnel's technology and operation in normal conditions and in exceptional situations. Thanks to this, they could work under the pressure with non-performance threat to the tunnel technology and safety of their users. The coordinator checks and assesses the correctness of their conduct

Simulation of emergency events with fire in virtual road tunnels

Road emergency events are very dangerous, especially if they happen in tunnels. If such an event occurs with the presence of fire, self-evacuation is the most important. From experience from catastrophic events in Alpine tunnels, people can only have a few minutes to rescue. It was also reason that a lot of changes in technology and safety tunnel equipment have been legislatively adopted. Then if we want to help rescue people, we need experienced tunnel operators, who know the principles of tunnel ventilation control with fire and smoke. This paper is about simulation of emergency events in virtual tunnel of Tunnel Traffic & Operation Simulator (Simulator) and about simulations of smoke stratification on the basis of Computer Fluid Dynamics (CFD) models

Increase of road tunnels safety using Tunnel Traffic & Operation Simulator

Tunnels, constructions used to shorten transport routes and to improve road safety, are specific engineering structures where the safe operation is very important. Tunnel Traffic & Operation Simulator (Simulator) was created as a solution of research task focused on increasing safety in road tunnels within the framework of the project “Centre of Transport Research (CVD)” funded by European Regional Development Fund (ERDF). The Simulator is located on Faculty of Civil Engineering of the University of Žilina (Slovakia) and is adapted to control the tunnel in two operator’s mode which are functionally convertible. They can during the operation of the simulator control the tunnel's technology and operation in normal conditions and in exceptional situations. Thanks to this, they could work under the pressure with non-performance threat to the tunnel technology and safety of their users. The coordinator checks and assesses the correctness of their conduct

Testing measurements of airflow velocity in road tunnels

Within the project entitled “Models of formation and spread of fire to increase safety of road tunnels”, it was necessary to devise a method how to record airflow velocity during the fire in situ tests in road tunnels. Project is in first year of its solution so one testing measurement was performed to check the functionality of anemometers selected for this project and the first in situ measurement was also performed just a few days ago

Evaluation of Bitumen Modification Using a Fast-Reacting SBS Polymer at a Low Modifier Percentage

The study presented in this paper investigates the application of asphalt bitumen modification using a fast-reacting SBS polymer at a low modifier percentage. The hypothesis is that a fast-reacting styrene–butadiene–styrene (SBS) polymer that composes only 2% to 3% of the weight of the bitumen modification could extend the life of the pavement surfacing and pavement performance at relatively low input costs, increasing the net present value produced by the pavement during its life cycle. To confirm or refute this hypothesis, two types of road bitumens CA 35/50 and 50/70 were modified with low amounts of fast-reacting SBS polymer with the expectation of attaining properties similar to a 10/40–65 modified bitumen. For each type of unmodified bitumen, bitumen modification and comparative 10/40–65 modified bitumen, the following tests were conducted: needle penetration, softening point—ring and ball test method, and ductility test. The second part of the article focuses on a comparison of asphalt mixtures with different compositions of coarse-grain curves. For each mixture, complex modulus with varying temperatures and fatigue resistances are represented by the Wöhler diagram and compared. Based on in labo testing, the impact of the modification on pavement performance is evaluated. Life cycle changes for each type of modified and unmodified mixtures are quantified as road user costs, and attained benefits are compared with increased construction costs