This study investigates the feasibility of using recycled concrete aggregate (RCA) as a partial substitution of natural aggregate in pavement engineering. Despite RCA’s good properties, such as polishing value and freeze-thaw resistance, its use is limited by low resistance to fragmentation and high-water absorption. This paper parent the experimental results of mineralogical-petrographic and physical-mechanical properties of RCA, natural stone (dolerite) and their combination (RCA content—15%, 30%, 45%, and 60%). The tested granular mixtures showed good resistance to fragmentation and wear (LA 22–27%, MDE 14–15%), as well as satisfactory Polished Stone Value of 55–57, which means they can be used in different layers of pavement structures. According to the obtained testing results, the application of RCA is possible in different flexible and rigid pavement layers and for various traffic loads.
Copper slag, a by-product of the pyrometallurgical process used for obtaining copper from copper ore in Bor, Serbia, contains mainly silicon, iron, calcium, and aluminium oxides. Due to such properties, it is disposed of in landfills. Despite the favourable technical properties copper slag aggregates possess, such as low-water absorption (WA24 0.6%), low resistance to fragmentation (LA 10%), and low resistance to wear (MDE 4%), its use in the construction industry is still limited. The results of testing the technical properties of copper slag aggregates (CSAs) as a potential replacement for natural river aggregate (RA) are presented in this paper. The experiments included tests on three concrete mixtures with partial replacement of coarse natural aggregate with copper slag. The replacement of RA particle sizes of 8/16 mm and 16/31.5 mm with CSA in the amount of 20% + 50% and 50% + 50% resulted in an increase in the compressive strength of 12.4% and 10.5%, respectively. The increase of CSA content led to a decrease in water penetration resistance and salt-frost resistance of concrete, whereas the resistance to chloride ion penetration did not change significantly.
Introduction:Subconjunctival hemorrhage or suffusion is bleeding that occurs between the conjunctiva and episclera. It has a distinctive look and often frightens patients. The causes can be varied. Objective: The research was undertaken in order to determine the characteristics of patients within whomsubconjunctival hemorrhage occur. Methods: Retrospective analysis of patients of the Eye Department of the Health Center in KosovskaMitrovica, during 6 months. Results were analyzed SPSS ver 22, i GraphPad INSTAT software package. Results: The change was observed in 63 patients. Male gender was significantly more frequent. The age of patients was diverse-between 5 and 86 years. The causes and conditions associated with subconjunctival hemorrhages are usually eye trauma, in young,and arterial hypertension in elderly patients. Conclusion: Subconjunctival hemorrhage is a relatively common diagnosis in ophthalmology. The change is benign and spontaneously disappears during one to two weeks. It is important to note that the subconjunctival hemorrhage occur in patients with certain risk factors.
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