Sažetak: Increasing the strength and durability of road surfaces is crucial. Therefore, the concrete compressive strength, flexural strength, frost, and abrasion resistance of fiber-reinforced concrete for rigid pavements are investigated in this study an experiment is performed based on an optimal plan, in which four factors of concrete composition are varied: the amounts of Portland cement, polypropylene fiber, metakaolin, and polycarboxylate type admixture. Experimental statistical models for investigating the effects of composition factors on concrete properties are established. It is discovered that owing to the use of metakaolin and a superplasticizer, the concrete compressive strength increases. Furthermore, the use of modifiers and fiber reinforcement increases the flexural strength, frost resistance, and wear resistance of concrete. X-ray phase analysis of the fiber-reinforced concrete structure confirm the effectiveness of the modifier effect, in particular the positive role of metakaolin as an active pozzolana. The developed fiber-reinforced concrete for rigid pavements with rational modifiers, depending on the Portland cement content, exhibits compressive strengths from 55 to 70 MPa, flexural strengths from 8 to 9.5 MPa, frost resistances from F350 to F450, and abrasion resistances from 0.3 to 0.4 g/cm2. Such properties ensure the high durability of fiber-reinforced concrete and allow it to be used on road pavements that support heavy loads and traffic.

Ključne riječi: Rigid pavement; fiber-reinforced concrete; metakaolin; polycarboxylate admixture.

Sažetak: The human population is currently on the rise and most Europeans live in urban areas, leading to increased urbanization. The change comes with its challenges, as cities, architecture, and urban spaces need to become more fluid, multi-functional, and innovative. This paper examines whether a change of use of public spaces, and functions of architectural and urban forms, can be used as an element in the implementation of sustainable urbanization. The theoretical framework of this paper focuses on literature findings relating to identified key aspects such as innovative approaches in changes of use — recycling and upcycling, green infrastructure and financial aspects, concepts of “right of the place”, and public participation. These aspects are addressed on both theoretical and practical levels, with the National Theatre in London as a case study. Findings convey that the change of use of spaces can be utilized to achieve sustainable urbanization, together with the management of functions and uses of architectural and urban forms. However, further research is needed with various stakeholders to identify a solid and inherent database, as a foundation on which the most optimal urban spaces would emerge, by identifying new functions and uses of urban space and architecture.

Ključne riječi: Change of use; sustainability; urbanization; functions of architecture; public space

Sažetak: Structural project is based on technical regulations, structural codes, construction conditions, and client requirements. Through the structural design process, some important decisions that can significantly affect the final result must be implemented. The most important factor for optimal design is the reduction in material and overall work costs. Selecting appropriate joint configurations that can reduce the overall weight and work on the structure is critical. To examine a significant number of possible configurations and their effect on structural behavior, the generative design method (GDM) is used. In this study, software is custom developed, and a relevant example of generative joint structural design is provided. The methodology for the optimal joint and structure design is described comprehensively. The final results show that the GDM is an effective methodology for application in the design of steel structures.

Ključne riječi: Generative design; EN 1993-1-8; automation; optimization; steel; beam-to-column joint.

Sažetak: The morphodynamics of an artificial gravel beach in the Bay of Rijeka (Ploče Beach) was analyzed. The morphological changes of the beach face were monitored through an intense situation of gravitational surface wind waves from the incident SSW direction. A numerical modeling technique was applied, after initially establishing a numerical model for wave deformation. A model for sediment transport was established based on its results. Both models were based on the finite volume method. In addition, the partial contribution of the longshore component of sediment transport was analyzed based on empirical formulae. The modeling results were verified by comparing the positions and amounts of eroded/accumulated material along the beach with the processing of terrain images in the form of point clouds. The erosion and accumulation positions of the beach sediment material, obtained by numerical model simulations, corresponded to the surveyed positions. The total volume of eroded and accumulated material based on terrain image processing corresponded to the model values.

Ključne riječi: Numerical model; sediment transport; wind waves.

Sažetak: Warm additives had wide popularity in recent years due to saving in energy and lowering emissions dealt with asphalt mixture production. Warm Mix Asphalt (WMA) is produced by using foaming technology or reducing -viscosity additives of binder to enhance the rheological properties. In this study, organic-based additives (Asphaltan A and Asphaltan B) are used to investigate their effect to minimize the viscosity and lower the temperature of asphalt mixture production. Bitumen is mixed with three doses of each additive: 1, 2, and 3% of its weight. The binder viscosity was measured by rotational viscometer with and without the additives at three different temperatures. The study showed that the organic additives have a positive impact on the behavior of the binder in terms of viscosity reduction and made enhancements in terms of bitumen properties. This result could be useful in the reduction of production temperature and quantity of odour emissions.

Ključne riječi: Warm mix asphalt; asphaltan a; asphaltan b; bitumen properties; organic additives

Sažetak: The aim of this work is to improve a method for determining the characteristic values of climatic loads according to a probabilistic model of the annual maxima sequence, by choosing a rational type of generalized extreme value distribution law. An analysis is provided regarding the suitability of using four types of distributions for describing a data collection of maximum values of climatic loads. Using example data from the meteorological stations of Ukraine, it is found that for coefficients of variation smaller than 0.85–1.0, it is advisable to use the double exponential Gumbel distribution (generalized extreme value distribution type-I), and at higher values of the coefficient of variation, it is advisable to use the Weibull distribution (generalized extreme value distribution type-III). Recommendations are provided for considering the accuracy in the estimations of the characteristic values of loads according to the probabilistic model for the annual maximum value series.

Ključne riječi: Annual maxima; characteristic values; climatic loads; probabilistic description