Water-Washed Fine and Coarse Recycled Aggregates for Real Scale Concretes Production in Barcelona

The use of recycled aggregate to reduce the over-exploitation of raw aggregates is necessary. This study analysed and categorised the properties of water-washed, fine and coarse, recycled aggregates following European Normalization (EN) specification. Because of their adequate properties, zero impurities and chemical soluble salts, plain recycled concrete was produced using 100% recycled concrete aggregates. Two experimental phases were conducted. Firstly, a laboratory phase, and secondly, an on-site work consisting of a real-scale pavement-base layer. The workability of the produced concretes was validated using two types of admixtures. In addition, the compressive and flexural strength, physical properties, drying shrinkage and depth of penetration of water under pressure validated the concrete design. The authors concluded that the worksite-produced concrete properties were similar to those obtained in the laboratory. Consequently, the laboratory results could be validated for large-scale production. An extended slump value was achieved using 2.5–3% of a multifunctional admixture plus 1–1.2% of superplasticiser in concrete production. In addition, all the produced concretes obtained the required a strength of 20 MPa. Although the pavement-base was produced using 300 kg of cement, the concrete made with 270 kg of cement per m3 and water/cement ratio of 0.53 achieved the best properties with the lowest environmental impact.

Fatigue Life Predictions for a European Pavement Test Section Subjected to Individual and Platoon Truck Configurations

Truck platooning for the transportation of loads is a strategy recently proposed by the automotive sector to cope with traffic congestion, fuel consumption, and operational costs. This new way of configuring trucks changes the typical pressures pavements structures experience. For this reason, the research efforts of the pavement sector should be aligned with the automotive sector to propose road-friendly platoon configurations. This is one of the objectives of the European project ENSEMBLE. ENSEMBLE, as indicated by its acronym, works on ENabling SafE Multi-Brand pLatooning for Europe. In this context, the present study presents a real scale test done in the Applus IDIADA facilities to evaluate the fatigue behavior of a pavement structure subjected to individual and platoon truck configurations. The effects of parameters such as traffic distribution through the year and by time of day, percentage of platoons, truck loads, number of trucks in platoon configuration, lateral wandering, and inter-truck distances were evaluated. The study’s findings revealed that the reduced rest times between trucks in the platoon configuration reduce the recovery time of the asphalt layers, increasing the fatigue damage to the pavement at high temperature conditions. This underlines the need for further research to allow the proper implementation of truck platoons. For example, research is needed to define strategies to make truck platoon configurations more pavement-friendly and analyze the costs associated with the changes in the required road maintenance/rehabilitation treatments, among others.

Perceived Sensations in Architectural Spaces through Immersive Virtual Reality

To design architectural spaces that not only respond to the basic needs of users, but also seek their emotional well-being, it is necessary for the architecture students to have a special sensitivity and be aware of the different sensations that their designs should and can evoke. To achieve this competence without exploring real spaces, Immersive Virtual Reality technology offers an important contribution to the field of architecture. The purpose of this research is to determine if the sensations perceived in virtual architectural spaces by students are similar to the real ones and to determine the characteristics of this technology that allow a better perception of sensations. Six architectural modules were designed to be walked through and experienced at real scale using a Head Mounted Display by 22 students of the first and fifth year of studies of Architecture career in Peru. An ad-hoc questionnaire allowed to know the perceived sensations and the benefits of the tool. The results obtained showed that the perception of sensations of the fifth year students is a little closer to those expressed by a group of seven experts compared to that of the first year students and that the students consider the characteristics of accessibility, real scale of the space and the possibility of going through and looking at the space in all directions are those that have given more realism to the experience and therefore better perception of the space, while the characteristics of natural light and shadows, construction materials and external environment have been less valued in the realism of the experience. It is concluded that the sensory experimentation in architectural spaces modelled realistically in virtual environments allows the perception of sensations very similar to those that the architect seeks to convey initially.

Chinas Economic Presence and Political Influence in Eastern Europe

In recent years, the media and expert discourse have widely spread perceptions of China’s dynamic expansion of its economic presence in Central and Eastern Europe and the accompanying increase in Beijing’s political influence on the countries of the region. This perception is strongly encouraged by the position of certain Western European countries and the EU bureaucracy, which view China as an actor that undermines European solidarity and spreads illiberal values and business practices. The purpose of this article is to assess the real scale of China’s economic presence in Eastern Europe, based on an analysis of official statistics, and to determine the extent to which it converts into Beijing’s political influence over the countries of the region.

Multiaxial Fatigue Life Assessment of Integral Concrete Bridge with a Real-Scale and Complicated Geometry Due to the Simultaneous Effects of Temperature Variations and Sea Waves Clash

In the present study, the authors attempted to predict the fatigue lifetime of a real-scale integral concrete bridge with H-shaped steel piles resulting from working and environmental conditions. In this regard, various types of nonproportional variable amplitude loads were applied on the bridge, such as temperature variations and sea waves clash. To this end, CATIA software was used to model the real-scale bridge with its accessories, such as a concrete deck, concrete anchors (walls), I-shaped concrete beams (Ribs), and steel piles. Subsequently, stress analysis was performed to determine the critical area apt to fail. The results showed that steel piles are the most critical bridge components. As a result, in future analysis, the purpose will be to study this critical area, and the effect of relative humidity on the fatigue properties of concrete was ignored. Subsequently, the time history of stress tensor components in the critical area was obtained by performing transient dynamic analysis. Various well-known equivalent stress fatigue theories (von Mises, Findley, Dang Van, McDiarmid, Carpinteri–Spagnoli, Modified Findley, Modified McDiarmid, and Liu–Zenner) were utilized to calculate the equivalent stress caused by the simultaneous effect of temperature variations and sea waves clash. Eventually, the fatigue life of the structure was predicted by employing the rainflow counting algorithm and the Palmgren–Miner damage accumulation rule. The results indicated a reduction in the multiaxial fatigue life of the structure under the simultaneous effects of two phenomena, the daily temperature variations and the sea waves clash, of approximately 87% and 66%, respectively, compared with the fatigue life of the structure under either the effect of temperature changes or the effect of sea waves clash, separately. Therefore, it was necessary to consider all the cyclic loads in the structural design step to estimate the fatigue life of the structure. Moreover, the findings of this case study revealed that the lowest value of multiaxial fatigue lifetime is related to the application of the Liu-Zenner criterion. In other words, this criterion is more conservative than the other used criteria.

Parameterized 2D Field Model of a Switched Reluctance Motor

This work aimed to develop a parameterized, two-dimensional field model of a switched reluctance motor (SRM). The main task of the developed model was to calculate the value of the electromagnetic torque for various positions of the rotor. Based on these calculations, the characteristics of the electromagnetic torque were determined depending on the position of the rotor angle φ for the current function I (T = f (φ, I)). Using the model, it was possible to additionally observe the phenomena occurring in the motor winding, e.g., distributions, isolines of magnetic potential, induction, and to calculate the values of the temperature. The parameterized structural elements that made up the entire model can be freely changed and, thus, the results for various structures can be obtained. Thanks to this, it was possible to evaluate and compare motor of different designs. To validate the model, measurements were conducted on real-scale reluctance motors, and families of electromagnetic torque characteristics were obtained for various design cases. The results received from the tested motors were juxtaposed with simulation results procured via the model. Based on this comparison, it was possible to determine the accuracy of the model’s operation.