ZAG Ljubljana

Ljubljana, Slovenia

ZAG Ljubljana

Ljubljana, Slovenia

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Bizjak K.F.,ZAG Ljubljana | Dawson A.,University of Nottingham | Hoff I.,Norwegian University of Science and Technology | Makkonen L.,VTT Technical Research Center of Finland | And 2 more authors.
Proceedings of the Institution of Civil Engineers: Transport | Year: 2014

Anticipated climate changes in Europe over the next 100 years were estimated using two different scenarios of carbon dioxide emissions and two computational approaches. The principal manifestations of climate change within the European region are predicted to be a rise in temperature, an increase in rainfall intensity in most areas and a decrease in freeze–thaw cycling. The impacts of such possible climate changes were then estimated for pavements and the pavement-related infrastructure. It should be noted that the life cycle of pavements is much shorter than the time span over which climate change might have a statistically significant influence on pavement performance. Several analytical and numerical analyses were performed in order to simulate the effect of future climate change, taking into account the fact that the effect of these changes on pavements structures will depend on local conditions. In particular, temperature and rainfall increase will be a challenge for asphalts, as both rutting and stripping of asphalt layers can be expected. In countries where roads are presently frequently frozen in winter, the length of this period of freezing will be reduced. For this reason, many thin and unsealed pavements will need to be upgraded if high bearing capacity is to be maintained. In coastal and low-lying areas raised water tables may occur due to areas where flood waters may collect, or due to raised sea levels. For most applications, appropriate responses to these changes in pavement performance will be achievable through the use of new design criteria with regard to temperature and the return period of storm flows.More attention needs to be paid to drainage systems, which should be self-cleaning and easy to inspect. © 2014, Thomas Telford Services Ltd. All rights reserved.


Cosic K.,Josip Juraj Strossmayer University of Osijek | Korat L.,ZAG Ljubljana | Ducman V.,ZAG Ljubljana | Netinger I.,Josip Juraj Strossmayer University of Osijek
Construction and Building Materials | Year: 2015

This study investigates the influence of aggregate type and size on the properties of pervious concrete. Five different concrete mixtures were prepared, including a standard dense concrete mixture and four pervious concrete mixtures with varied aggregate types (dolomite or steel slag) and differing proportions of 4-8 mm to 8-16 mm aggregate fractions (30:60 or 60:30). The results suggest that a higher amount of small aggregate fractions (4-8 mm) yielded higher density concrete mixtures and greater flexural strength. However, connected porosity as a main parameter for estimating pervious concrete efficiency was surprisingly influenced more by the aggregate type than the size. © 2015 Elsevier Ltd. All rights reserved.


Korat L.,ZAG Ljubljana | Ducman V.,ZAG Ljubljana | Legat A.,ZAG Ljubljana | Mirtic B.,NTF
Ceramics International | Year: 2013

In the case of lightweight aggregate (LWA), porosity can be achieved by means of a high temperature foaming process. During this process a glassy matrix is created, and almost simultaneously the added foaming agent degasses and the resulting gasses remain trapped inside the glassy structure. The present paper deals with the foaming process which occurs in the case of silica sludge to which fly ash, which creates liquid phase, has been added, as well as SiC, which acts as a foaming agent. The development of porosity within the structure of this material was investigated at different temperatures and dwelling times by means of X-ray micro-tomography (micro-CT), and mercury intrusion porosimetry (MIP). The results were compared by means of both X-ray micro-tomography and mercury intrusion porosimetry, the first technique being applied within the pore size distribution range of between 50 μm to more than 1 mm, and the second within the range, between 0.0055 and 360 μm. Both techniques have certain limitations as well as certain advantages, but in the case of the investigated system micro-CT gives much more reliable results about porosity development over a prolonged firing time, at the selected temperature. The results showed that, at the selected temperature, which in this case amounted to 1220 °C, porosity as well as median pore size increased with increased dwelling times. In the case of prolonged dwelling times, the number of pores decreased, but, on the other hand, the volume of these pores increased. © 2013 Elsevier Ltd and Techna Group S.r.l.


Tusar M.,Kemijski Institute Ljubljana | Turk M.R.,ZAG Ljubljana
Gradjevinar | Year: 2015

A full-scale accelerated structural load test was performed in the scope of field trials conducted to investigate the effect of various strengthening actions on weak pavements. The asphalt layer thickness varied from 6.5 cm to 13.6 cm. The results of deformations applied on test structures are presented in the paper. The loading of each test structure lasted for approximately 2 weeks. Clear dependence between the depth of permanent deformation and thickness of asphalt layers was established on thin pavement structures only. © 2015, Union of Croatian Civil Engineers and Technicians. All rights reserved.


Ducman V.,ZAG Ljubljana | Korat L.,ZAG Ljubljana | Legat A.,ZAG Ljubljana | Mirtic B.,NTF
Materials Characterization | Year: 2013

In case of foamed lightweight aggregates (LWAs), porosity is introduced by the addition of a foaming agent to the glassy matrix, which degasses at an elevated temperature, so that the resulting gases remain trapped inside the glassy structure. The efficiency of action of MnO2 as a foaming agent in waste glass and waste glass/silica mud systems was studied. Samples were fired at different temperatures and with different dwelling times at a certain temperature, and the development of porosity was investigated by means of X-ray micro-tomography. It was found that, with the prolongation in dwelling times, the number of pores decreased, while, on the other hand, the volume of these pores increased, and that the addition of silica mud increases the foaming temperature and slows down the foaming process. © 2013 Elsevier Inc.


Radeka M.,University of Novi Sad | Ranogajec J.,University of Novi Sad | Marinkovic-Neducin R.,University of Novi Sad | Ducman V.,ZAG Ljubljana | Skapin A.S.,ZAG Ljubljana
C e Ca | Year: 2010

Frost resistance of roofing tiles is of both practical and scientific interest, especially since the frost action mechanisms are still not well understood. Textural characteristics and low temperature dilatometrical behavior (from -40 to +40 X) of day roofing tiles are correlated with the type of frost damage identified by the standard procedure, EN 539-2, method C, giving the insight into the dominant frost action mechanism (mechanism of closed container, hydraulic pressure, and the ice lens mechanism). The samples of clay roofing tiles from the same batch were fired in laboratory conditions at different temperatures (920, 970, 995, 1005, 1055 and 1085 oC) and in the industrial plant (1100 oC). Based on the mentioned correlations, the change of the dominant frost action mechanism is explained by porous structure differentiation with the temperature, from a closed container at lower to micro ice lens formation at higher temperatures, with the hydraulic pressure mechanism contributing considerably in all the temperatures. The obtained correlations are of specific importance in taking fast and right corrective measures in a defined production line in order to improve the frost resistance characteristics of the final product.


Radeka M.,University of Novi Sad | Ranogajec J.,University ofNoviSad | Marinkovic-Neducm R.,University ofNoviSad | Ducman V.,ZAG Ljubljana | Skapin A.S.,ZAG Ljubljana
Industrial Ceramics | Year: 2010

Frost resistance of roofing tiles is of both practical and scientific interest, especially since the frost action mechanisms are still not well understood. Textural characteristics and low temperature dilatometrical behavior (from -40 to +40 °C of clay roofing tiles are correlated with the type of frost damage identified by the standard procedure, EN 539-2, method C, giving the insight into the dominant frost action mechanism (mechanism of closed container, hydraulic pressure, and the ice lens mechanism). The samples of clay roofing tiles from the same batch were fired in laboratory conditions at different temperatures (920, 970, 995, WIS, 1055 and 1085 °C and in the industrial plant (1100 °C). Based on the mentioned correlations, the change of the dominant frost action mechanism is explained by porous structure differentiation with the temperature, from a closed container at lower to micro ice lens formation at higher temperatures, withthe hydraulic pressure mechanism contributing considerably in all the temperatures. The obtained correlations are of specific importance in taking fast and right corrective measures in a defined production line in order to improve the frost resistance characteristics of the Final product.

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