Evaluation of optimal replacement of natural aggregates by recycled concrete aggregates to achieve sufficient durability

The use of recycled concrete aggregate (RCA) is one way to reduce the depletion of raw materials for the production of concrete. In this article RCA was tested and evaluated. Concrete with 25 to 80 % of RCA was examined in terms of its durability performance, particularly capillary absorption and shrinkage. Capillary absorption testing showed that RCA has better or identical results as the reference mixture. Concrete with a high proportion of RCA had reduced durability, even with reduced durability the concrete maintains all the requirements of the Norwegian Standard. RCA as partial replacement in smaller quantities show good properties

PREGLED DOSTIGNUĆA PRIMJENE BIM KONCEPTA U HRVATSKOJ, ČEŠKOJ, NJEMAČKOJ I SLOVENIJI

Building information modelling (BIM) may currently be considered the fastest developing concept in the field of construction management, aiming to become a global standard. Although the roots of the concept date back to the mid-1970s, some original expectations are still missing from its implementation. There has been a time gap between its theoretical and practical implementations. While the simultaneous development of information technologies is one reason for the implementation delay, other reasons remain unclear. This paper analyzes the gaps between theoretical and practical BIM application, as well as the legislation regarding BIM implementation in four countries (in alphabetical order: Croatia, the Czech Republic, Germany, and Slovenia). The paper additionally presents a survey of current practical BIM applications as well as general and theoretical feedback from construction projects that implemented BIM.Jedan od najbrže razvijajućih koncepata u domeni metoda i alata za upravljanje građevinskim projektima, uz konačni cilj da postane globalni standard, je informacijsko modeliranje građevina, tj. BIM. Iako se koncept razvija od sredine 1970-ih, neka od originalnih očekivanja u njegovoj primjeni i danas nedostaju. Očito je da postoji vremensko odstojanje između njegove teorijske i praktične primjene. Istovremeno, razvijanje nužnih alata informacijske tehnologije je jedan od razloga zašto praktična primjena zaostaje, no ostali razlozi su još nejasni. U ovome radu autori analiziraju razlike između teoretske i praktične primjene BIM-a u zemljama odakle dolaze (Hrvatske, Češke, Njemačke i Slovenije). Rad predstavlja pregled trenutačnih dostignuća primjene BIM-a te povratnih informacija s projekata na kojima je BIM primijenjen

Effect of Microwave Radiation on the Compressive Strength of Solid Ceramic Brick

Microwave radiation is widely utilized in construction practice, especially for drying building materials, remediating damp masonry, or sterilization of biotic pests that have infested building structures. The available scientific and technical literature reports that certain materials exposed to microwave radiation do not change their physical and mechanical properties, although this has not yet been adequately verified. This paper builds on many years of research in the area, adding to and refining existing information, providing new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and comparing them with reference values. The experimental research on a set of clay brick samples is carried out using tests according to European standards, and it focuses on the effect of microwave radiation on compressive strength and water absorption. The experimental samples were compared to reference samples that had not been subjected to prolonged exposure to moisture and were subsequently treated with microwave radiation for dehumidification

Optimierung von Bauprozessen – Methoden, Werkzeuge und Anwendung

U radu je dan pregled suvremenih heurističkih tehnika i metoda matematičkog programiranja. Predstavljeni su moderni alati za optimizacijsko modeliranje, izlažu se najčešći problemi optimizacije u građevinarstvu i daje pregled njihovih nedavnih aplikacija. Rad je istaknuo prostor istraživanja na aktivnim modelima optimizacije, koji su podržani BIM-om s namjerom boljeg upravljanja građevinskim procesima. Ubrzani razvoj modela odlučivanja, koji kombiniraju optimizacijske metode i informacijske sustave, jasno se može predvidjeti za blisku budućnost.A review of current heuristic techniques and mathematical programming methods is presented in the paper. Modern optimisation modelling tools are presented, common construction optimisation problems are described, and an overview of their recent application is given. It is also stressed that there is ample room for further research on active BIM-based optimisation models, aimed at better management of construction processes. Accelerated development of decision-making models, which combine optimisation methods and information systems, can be clearly predicted for the near future.In der Abhandlung wird eine Übersicht über die modernen heuristischen Techniken und Methoden der mathematischen Programmierung dargelegt. Vorgestellt werden moderne Werkzeuge für die optimierte Modellierung, es werden die häufigsten Probleme der Optimierung im Bauwesen dargelegt und es wird eine Übersicht ihrer aktuellen Anwendungen gegeben. Die Abhandlung betont den Untersuchungsbereich aktiver Modelle der Optimierung, die durch BIM unterstützt werden, mit dem Ziel eines besseren Bauprozessmanagements. Eine beschleunigte Entwicklung der Entscheidungsmodelle, welche die Optimierungsmethode und die Informationssysteme kombinieren, kann für die nahe Zukunft klar vorausgesehen werden

Effect of Microwave Radiation on the Compressive Strength of Solid Ceramic Brick

Microwave radiation is widely utilized in construction practice, especially for drying building materials, remediating damp masonry, or sterilization of biotic pests that have infested building structures. The available scientific and technical literature reports that certain materials exposed to microwave radiation do not change their physical and mechanical properties, although this has not yet been adequately verified. This paper builds on many years of research in the area, adding to and refining existing information, providing new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and comparing them with reference values. The experimental research on a set of clay brick samples is carried out using tests according to European standards, and it focuses on the effect of microwave radiation on compressive strength and water absorption. The experimental samples were compared to reference samples that had not been subjected to prolonged exposure to moisture and were subsequently treated with microwave radiation for dehumidification