Title Ispitivanje cementnog morta ultrazvukom Title (english) Ultrasonic pulse velocity investigation of cement mortar Author Igor Radić Mentor Gojko Balabanić (mentor)Committee member Ivica Kožar (predsjednik povjerenstva)Committee member Silvija Mrakovčić (član povjerenstva)Committee member Gojko Balabanić (član povjerenstva)Granter University of Rijeka Defense date and country 2016-09-28, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Tematika koju ovaj rad problematizira vezivno je sredstvo - mort. U građevinarstvu sredstvo je to koje se najčešće koristi za povezivanje zidnih elemenata. Provedena su ultrazvučna ispitivanja kojima su mjerene brzine prolaska ultrazvučnog impulsa kroz uzorke u obliku prizme različitog vodocementnog omjera. Zamiješano je ukupno pet mješavina vodocementnih omjera: 0,45; 0,50; 0,55; 0,60; 0,65. Udio cementa u svim mješavinama jednak je, što znači da se mijenjao udio agregata i vode. Osim provedenog ultrazvučnog ispitivanja, ispitivalo se vlažnost, gustoću te vlačnu i tlačnu čvrstoću uzoraka cementnog morta. Ispitivanja su provedena na uzorcima prirodne vlažnosti starosti 3, 7 i 28 dana pri čemu su se, tokom svakog ispitivanju koristila 3 uzorka. Također, ispitivali su se vodom zasićeni jednako kao i suhi uzorci kako bi se prikazao utjecaj vlažnosti na brzinu ultrazvuka i utjecaj zasićenja na vlačnu i tlačnu čvrstoću. Obradom rezultata utvrđeno je da uzorci mješavine nižih vrijednosti vodocementnih omjera rezultiraju višim vrijednostima gustoće, čvrstoće, a time i većom brzinom ultrazvučnog impulsa. Veći vodocementni omjer pretpostavlja veći udio vode i manji udio agregata, što zatim dovodi do povećane poroznosti i smanjenja elastičnosti cementnog morta, a nadalje se odražava na čvrstoću i brzinu širenja ultrazvučnih valova. Najviše vrijednosti ispitivanja tlačne i vlačne čvrstoće te brzine ultrazvuka izmjerene su na uzorcima starosti 28 dana. Takav rezultat dobiven je iz razloga višeg stupnja hidratizacije kao i činjenice da su predmetna ispitivanja provedena na vodom zasićenim uzorcima.
Abstract (english) Mortar is in civil engineering most often used as a binder for connecting wall elements. Ultrasonic pulse test has been conducted in investigation which measured the propagation velocity of ultrasonic pulse through the specimen in the form of prisms of different watercement ratio. In total five mixtures were mixed with watercement ratio 0.45; 0.50; 0.55; 0.60; 0,65. The content of cement in all mixtures was equal, which means that the content of water and aggregate change. Except of the ultrasonic pulse investigation, the investigation was also examining humidity, density, tensile and compressive strength of cement mortar specimens. Following tests were performed on specimens with natural humidity after 3, 7 and 28 days where each investigation was using 3 specimens. The saturated and dry specimens also were investigated to show the effect of humidity on the velocity of ultrasonic pulse and saturation effect on tensile and compressive strength. Analyzing the results it is concluded that the specimens of mixture with the lower watercement ratio showed higher values of density, strength, and with it the larger ultrasonic pulse velocity. The higher watercement ratio means higher water content and lower content of aggregate, which further leads to increased porosity and reduced elasticity of cement mortar which reflects on the strength and velocity of the ultrasonic waves. The highest values of compressive and tensile strength and ultrasonic velocity tests were tested on the specimens after 28 days by the fact of a higher
Keywords
Mort
ultrazvučno ispitivanje
tlačna čvrstoća
vlačna čvrstoća
gustoća
vlažnost
Keywords (english)
Mortar
ultrasonic pulse velocity test
compressive strenght
tensile strenght
density
humidity
Language croatian URN:NBN urn:nbn:hr:157:956548 Study programme Title: Civil Engineering; specializations in: Geotechnical Engineering, Hydraulic Engineering, Engineering Modelling, Structural Engineering, Transportation Engineering, Urban Engineering Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2016-12-16 11:43:17
