Construction and demolition waste (C&D waste) is one of the most relevant waste types primarily due to large quantities and a high potential for re-use and recycle. This paper discusses the issues related to C&D waste management in the Republic of Croatia. It presents the overview of legislative changes and its impact on the C&D waste management in Croatia. C&D waste quantities per county in the period from 2001 to 2015 are given as well as the expected C&D waste quantities in the future. It is concluded that the legal framework is well established, but it is not implemented consistently. Therefore, it is necessary to plan certain activities and additional resources in order to make the C&D waste management more efficient. The paper also presents the options of C&D waste recycling and describes the recycling technology in a C&D waste recycling plant in the Republic of Croatia. Taking into account the relatively low price of recycled aggregate, long distance transport is not profitable. It is concluded that the use of mobile treatment facilities would be a good practical solution taking into account the underdeveloped infrastructure for C&D waste management.

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This article presents geotechnical reconnaissance data that characterize the formation of 122 new and 49 historical cover-collapse sinkholes within 1.13 km2 area in 12 months following the MW 6.4 earthquake that occurred on 29 December 2020, in Petrinja, Croatia. Data include a geological background, seismic sequence information, sinkhole geometric characteristics, rainfall data, and results of detailed geotechnical subsurface investigation. The sinkhole geometrical features were collected using aerial and satellite imagery, terrestrial lidar, and manual measurements. Soil properties and groundwater levels were obtained from four geotechnical boreholes, accompanied by in situ geotechnical characterization and standard penetration tests (SPTs). Soil parameters were obtained from consolidated undrained conventional triaxial compression, oedometer, soil water retention, and index tests performed on 31 soil samples. Clayey cover, 4–10 m thick, with sporadic gravel lenses overlying cavernous, intensely karstified carbonate rocks, characterizes the sinkhole area. Clays are mostly overconsolidated, with varying degrees of saturation ranging from very small to fully saturated. Seasonal and climate-induced variations in the groundwater table interact with artesian/subartesian karst aquifer, thus affecting the suction and the shear strength. Soil water retention curves (SWRCs) indicate that desaturation is possible for deeper groundwater tables, thus further affecting the effective stress, shear strength, and interparticle tensile forces. Finally, the observed vertical walls that accompanied sinkholes opening can occur in the overconsolidated cohesive cover clay layer with varying degree of saturation. The presented data provide essential geomechanical information necessary to understand the associated sinkhole failure mechanism. This article will help future investigators to perform detailed analyses and provide a background for complementing future sinkhole precursor research. Geotechnical, geological, seismic, and precipitation data generally indicate that the formation of cover-collapse sinkholes in the study area is a consequence of a specific local geological setting but is significantly expedited by earthquake-induced dynamic loading and complemented by multiple hydro-mechanical factors.

The Unified Soil Classification System (USCS) is the basis for numerous methods for soil trafficability research. Since USCS data are not always available, various other data and methods are used to correlate and predict the USCS soil group. This paper describes two methods used for the purpose of mapping Continental Croatia (CCro) according to USCS to a depth of 50 cm. In the first method, the possibility of transfer of 308 profile samples according to the International Soil Science Society (ISSS) classification system into USCS was examined. The results show that it is impossible to directly transform ISSS data into USCS. In the second method 414 USCS profiles were used to analyse the weights of factors in the spatial analysis with inverse distance weighting (IDW). The analysis included layers of dominant and associated soil units of the Basic Soil Map of Croatia (BSM), Geological Map of Croatia (GM), drainage and catchment areas. The obtained weights were as follows: BSM 47,12%, catchment area 27,12%, GM 17,67% and drainage 8%. The results showed that CCro is covered with fine-grained soils, with clay covering almost the entire area and silt dominating in the western and north-western parts of the country.

Our distinguished professor, Davorin Kova i , passed away on February 17 th , 2019. He was a member of the Faculty of Mining, Geology and Petroleum Engineering from 1991 to 1996, and he participated in scienti c and professional work with numerous colleagues at the Faculty of Mining, Geology and Petroleum Engineering in the elds of geotechnical engineering and environmental geotechnics. Professor Davorin Kova i was born in Zagreb on March 29 th , 1945, where he nished elementary school and grammar school. He enrolled in the Faculty of Civil Engineering, at the University of Zagreb in 1964, graduated in 1969, and was awarded the title of a graduate engineer in civil engineering. He obtained his Master's degree in 1976 with the theme "The analysis of an excavation process using nite elements and critical state model" at The College, Swansea University, Wales, UK. He received his doctorate in 1989 at the Faculty of Civil Engineering, University of Zagreb with the topic "Nu meri ko rješavanje dvodimenzionalne konsolidacije tla" ("Numerical analyses of two-dimensional soil consolidation") and gained the academic title of Doctor of Technical Sciences, in the eld of civil engineering. In 1970, he was employed at the Department for Concrete Structures of the Faculty of Civil Engineering of the University of Zagreb as an expert associate. As early as 1972, he moved to the company Geotehnika-Institut Geoexpert, Zagreb as an associate designer. From 1974 to 1975, he resided in the United Kingdom as a postgraduate student at The College, Swansea University, Wales. After that, he returned to the Institut Geoexpert, rst as a designer and later as a group manager. After gaining the academic degree of Doctor of Technical Sciences, from 1989 to 1991 he became the manager of the Depatment for Research and Development of Geotehnika, Zagreb. In that period, he had already started his academic career. From 1983 to 1990, he was a guest lecturer for the subject of Foundations at the Faculty of Civil Engineering, University of Mostar. In 1991, he was employed at the Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb, rst as an assistant professor, and later as an associate professor of technical sciences, in the eld of civil engineering, branch of geotechnics. He was the lecturer for the subjects: Soil mechanics and foundation engineering, Geotechnical structures, Numerical methods in soil and rock mechanics and Geotechnical Principles of Land lls. He also taught the course Application of numerical methods in geotechnics in the postgraduate study of Faculty of Mining, Geology and Petroleum Engineering. After that, he returned to the economic sector where he was the general manager of the company BBR Conex, d.d.