The effect of aggregate grading on physical and mehanical properties of concrete

Beton je složeni građevinski materijal koji zauzima sve veću ulogu u današnjem svijetu, a posebno građevinarstvu. Sastavljen je od cementa, agregata, vode i aditiva. Provedena su ispitivanja svježeg i očvrslog betona u 6 različitih mješavina. Ulazni podaci za ispitivanja i projektiranje betona bile su dvije različite granulometrijske krivulje – kontinuirana i diskontinuirana te vodocementni omjeri: 0,5, 0,55 i 0,6. Cement je u radu predstavljao konstantu pa su tako frakcije i omjer vode bile varijable. Ispitivanja provedena na svježem betonu su ispitivanja: konzistencije, gustoće i sadržaja zraka. Ispitivanja provedena na očvrsnulom betonu, a radi ispitivanja mehaničko - fizikalnih svojstava betona su ispitivanja: tlačne čvrstoće betona, vlačne čvrstoće i prodora vode kroz uzorak. Prema analizi ispitivanja kontinuirana granulometrijska krivulja dala je veće čvrstoće na tlačna i vlačna naprezanja te veću otpornost na prodor vode od diskontinuirane krivulje. Povećanjem vodocementnoga omjera u svim primjerima došlo je do smanjivanja mehaničkih i fizikalnih svojstava betona.Concrete is a complex building material used more often than ever before, with main purpose on construction sites. It is made of cement, aggregates, water and additives. We made 6 tests on fresh and hardened concrete. Input data for tests and concrete design were two aggregat gradings – continuous and discontinuous. Watercement ratio was 0,5; 0,55 and 0,6 while cement ratio was constant during mixtures, meaning watercement ratio and aggregate gradings were variables. Tests conducted on fresh concrete are tests of consistency, density and air content. Tests conducted on hardened concrete are tests of tensile strength, compressive strength and water penetration. Based on examination made on materials, continuous aggregat grading had better resistence on tensile strength, compressive strength and water penetration than discontinuous aggregate grading. Watercement ratio is a factor that was reducing mehanical and physical conditions in all examinations by enlarging