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Kako bi se ocijenila kvaliteta pepela s dna peći i utvrdila mogućnost njegove upotrebe u kompozitnim materijalima, provedeno je ispitivanje njegovih kemijskih, fizikalnih i mehaničkih svojstava iz dvije termoelektrane.Utvrđeno je da uzorci pepela s dna peći iz obje elektrane pokazuju dobra svojstva koja upućuju na mogućnost njihove praktične primjene te da ispunjavaju većinu kriterija propisanih za leteći pepeo. Ispitani su uzorci s 4 %, 8 %, 12 % i 16 % zamjene sitnog agregata pepelom. Rezultati su zadovoljili kriterije propisa za beton, što opravdava upotrebom pepela s dna peći u građevinskoj industriji., Chemical, physical and mechanical properties of bottom ash from two thermal power plants were analysed in order to evaluate the quality of bottom ash and to determine the possibility of its use in composite materials. It was found that the bottom ash samples from both power plants show good properties enabling their practical use, and that they also meet most of the criteria specified for fly ash. Samples in which 4, 8, 12 and 16% of fine aggregate was replaced with bottom ash were tested. The results meet criteria of applicable regulations for concrete, which justifies the use of bottom ash in construction industry.

U radu je prikazan utjecaj dva agresivna rastvora – sulfata i nitrata na žbuku i beton. U eksperimentalnom radu ispitivane su prizme od žbuke s 5 % specijalnog dodatka. Četiri vrste betona su također izložene agresivnim rastvorima. Kemijska otpornost ispitivana je prema metodi Koch-Steinegger. Kako je uvjet za otpornost kod agresivnih rastvora da zatezna čvrstoća žbuke nije niža od 70 % u odnosu na referentne prizme njegovane u vodi, može se zaključiti da žbuka i beton izrađeni s kombinacijom cementa i dodataka, prikazani u ovom istraživanju, nisu otporni na rastvor amonijak nitrata ali jesu na sulfatnu koroziju., Testing the influence of two aggressive solutions - sulphate and nitrate on mortar and concrete was presented in this paper. Experimental work included testing of mortar prisms with 5 % special admixture. Also, four types of concrete were exposed to aggressive solutions. The chemical resistance was tested according to the Koch-Steinegger method. As a condition for resistance in aggressive solution means that flexural strength of mortar prisms is no less than 70 % of referent prisms cured in water it can be concluded that mortar and concrete made with combination of cement and admixture presented in this investigation are not resistant to ammonium nitrate solution, but are resistant to sulphate corrosion.

Many parameters influence on the characteristics of fresh and hardened concrete. One of the most important characteristic of concrete is its porosity. Measure the porosity of fresh concrete is measured by the amount of entrained air. The effect of entrained air in concrete on compressive strength investigated by many authors. On the bases these works we have two formulas applicable in practice. Soft programming techniques especialy neural networks and the formation of databases related to the testing in laboratories for concrete opened up new approaches in predicting the impact of the quantity of entrained air in concrete on compressive strength.

Predmet istraživanja su betoni spravljeni sa recikliranom opekom kao agregatom. Eksperimentalni rad je obuhvatio više vrsta betona spravljenih sa istom količinom cementa (385 kg/m3) i istom konzistencijom (sleganje oko 1 cm). Kao agregat je korišćena reciklirana opeka i kombinacija reciklirane opeke i prirodnog rečnog agregata. Posmatran je uticaj upotrebljenih frakcija drobljene opeke i njihovog procentualnog učešća na čvrstoću pri pritisku, upijanje vode i otpornost prema dejstvu mraza. Na osnovu rezultata eksperimentalnih istraživanja može se zaključiti da se primenom reciklirane opeke kao agregata dobija novi kompozitni materijal sa zadovoljavajućim fizičko - mehaničkim karakteristikama. The investigation included concrete made by using recycled brick as aggregate. Experimental work included several types of concrete made with the same cement content (385 kg/m3), and same consistency (slump about 1 cm). Recycled brick and combination of natural river aggregate and recycled brick were used as aggregates. The influence of percentage and grain size of crushed brick aggregate on concrete compressive strength, water absorption and frost resistance were observed. On the basis of the results obtained during experimental research, a general conclusion can be drawn that the application of recycled concrete as aggregate can lead to new composites with satisfactory physical-mechanical properties.

For reconstruction of northwest breakwater in Tripoli harbour / Libya, about 4500 m long, it is necessary to produce various concrete elements (cubes and accropodes) in total amount of 550000 m 3 . Volumes of cubes are 6.3, 8.5 and 12.7 m 3 , volumes of accropodes are 6.3 and 9.0 m 3 . After preliminary trials and trial production optimum mix proportion has been chosen, meeting requirements of Technical specifications. One of the reasons for concrete blocks cracking is temperature difference between core and outher surface of the blocks, so we made blocks with new mix proportions (three different cement content). Measuring of temperatures has been performed in three characteristic points: in the middle of the cube, in the middle of vertical outer surface and in the middle of horizontal upper edge. Finally we accepted optimal mix proportion.

U svetu se vrše istraživanja mogućnosti ponovne upotrebe - recikliranja otpadnog građevinskog materijala, nastalog rušenjem postojećih objekata. Ova istraživanja obuhvataju selekciju otpadnih materijala čije je recikliranje tehnološki moguće i ekonomski isplativo, kao i koncipiranje tehnološkog procesa njihovog izdvajanja. Istraživanja obuhvataju i primenu tako dobijenih sirovina za modeliranje adekvatnih novih građevinskih materijala zadovoljavajući mehaničkih i fizičkih svojstava, kao i tehnologiju njihovog spravljanja. Possibilities of recycling waste building material got after demolishing of existing buildings are investigated in the world today. The investigations include selection of waste materials whose recycling is technological process of their extraction. These investigations are also focusing on the use of recycling materials for modeling of the relevant new building materials with satisfactory mechanical and physical properties as well as their production technology.

Na osnovu zavisnosti napona i deformacija pri kratkotrajnom opterećenju može se definisati područje elastičnih i plastičnih deformacija, karakter loma, maksimalna deformacija pri lomu. U ovom članku su prikazani radni dijagrami betona, kao i vrednosti statičkog i dinamičkog modula elastičnosti dobijeni na osnovu ispitivanja prema važećim jugoslovenskim standardima. Eksperimentalni rad je obuhvatio vise vrsta betona spravljenih sa agregatom od reciklirane opeke, sa ili bez dodatka polimera. . On the base of the dependence of stress and strained by loading of short duration, it is possible to define the area of elastic and plastic deformations, the failure character and the maximal failure deformation. In the present article the working concrete diagrams are presented, as well as the values of the static and dynamic modulus of elasticity, obtained on the base of testing according to the valid Yugoslav standards. The experimental work has comprised several kinds of concrete, fabricated with the aggregate of recycled brick, with or without polymer additives. .

Termička svojstva materijala u primeni određuju takozvane projektne termičke vrednosti koeficijenata toplotne provodljivosti građevinskih materijala. Predmet rada su rezultati serije laboratorijskih merenja koeficijenata toplotne provodljivosti lakih betona sa agregatom od reciklirane opeke, sa sadržajem cementa od 250 ili 350 kg/m3, sa ili bez polimera. Rezultati ispitivanja dali su podatke o boljim termičkim svojstvima ovih betona u odnosu na postojeći deklarisani opseg vrednosti (ISO TR 9165), a komentarisani su u odnosu na količinu cementa, količinu polimera, vrstu agregata, zapreminsku masu. . The technical properties of materials in application are defining the so called design thermal values of thermal conductivity coefficients of building materials. The item of this work are the results of laboratory measurements of thermal conductivity coefficients of lightweight concrete with aggregate of recycled brick, with the content of cement of 250 or 350 kg/m3, with or without polymers. The test results have given data with better thermal properties of these concretes in comparison with the existing declared perimeter of values (ISO TR 9165), and they are commented in relation to the cement quantity, polymer quantity, kind of aggregate, volume of the mass. .

U radu je prikazana mogućnost upotrebe reciklirane opeke kao agregata za beton. Eksperimentalni rad je uključio vise vrsta betona spravljenih sa 350 kg/m3 cementa i sa ili bez dodatka polimera. Kao agregat je korišćena kombinacija rečnog peska i reciklirane opeke. Izloženi su rezultati komparativne analize betona na bazi reciklirane opeke na sledeća svojstva betona: čvrstoću pri pritisku, statički i dinamički modul elastičnosti zavisnost napona i deformacija i dilatacije skupljanja. Possibility of using recycled brick as a component (aggregate) of concrete is shown in this paper. Experimental work included few kinds of concrete, made with the same cement content (350 kg/m3) and with or without polymer admixture. Combination of river sand and recycled brick were using as aggregate. The results of comparative analyze of concrete based on recycled brick are shown. Investigations included follow properties: compressive strength, statical and dynamical module of elasticity, stress-strain dependent and shrinkage dilatation.

U radu je prikazana mogućnost upotrebe reciklirane opeke kao agregata za beton. Eksperimentalni rod je uključio vise vrsta betona spravljenih sa dve količine cementa (250 i 350 kg/m) i sa ili bez dodatka polimera. Kao agregat je korišćena kombinacija rečnog peska i reciklirane opeke. Izloženi su rezultati komparativne analize betona na bazi reciklirane opeke na sledeća svojstva betona: čvrstoću pri pritisku, čvrstoću na zatezanje, vodonepropustljivost, otpornost betona prema dejstvu mraza, statički modul elastičnost i toplotnu provodljivost. . Possibility of using recycled brick as a component (aggregate) of concrete is shown in this paper. Experimental work included few kinds of concrete, made with the different cement content (250 and 350 kg/m) and with or without polymer admixture. Recycled brick or combination of river sand and recycled brick were using as aggregate. The results of comparative analyze of concrete based on recycled brick are shown. Investigations included follow properties: compressive and bending strength, waterproof, frost resistance, module of elasticity and thermal conductivity. .