@article{
author = "Vasović, Dejan and Folić, Radomir J. and Vasović, Tomislav",
year = "2008",
abstract = "During the winter time construction of the concrete structures, it is not uncommon to expect occasional short periods of the cold weather with temperatures below 0°C, which can last for few days, when freezing of the water in the fresh concrete might permanently destruct the newly formed cement matrix. This paper presents the results of an investigation of new type of chemical admixture which protect fresh concrete from the frost during very low temperatures (up to - 50°C) and enables continuation of the concrete hardening process when outside temperature becomes favorable. The testing included the admixture's influence on fresh concrete mixture and on the hardened concrete, with and without low temperatures influence. The concrete specimens were cured in the water at the 20°C temperature, and the results showed that the tested admixture caused the increase of the compression strength of more than 10% comparing to one of the reference specimen. In order to test the admixture influence, three cases of the potential low temperatures were examined. In thesis simulations, in order to establish the limits of the admiture's influence, fresh concrete mixture was exposed to the temperatures, where the lowest was -25°C. All three cases showed better behavior of the fresh concrete mixture, and also displayed much higher compression strength (for more than 100% higher, and for some regimes, for 200% higher). The specimens exposed to the extreme regime (the third one) were also tested for the water absorption and release, in order to establish the degree of destruction caused by frost and low temperatures during concrete hardening. These tests also showed that the specimens with the admixtures had lower water absorption, i.e. preserved structure of the concrete., Prilikom izvođenja betonskih konstrukcija na licu mesta u zimskom periodu nisu retki slučajevi kada se može očekivati kratkotrajno zahlađenje od nekoliko dana sa temperaturama ispod nule koje mogu dovesti do zaleđivanja vode u svežem betonu i stvaranja leda koji trajno oštećuje strukturu tek formiranog cementnog kamena. U radu su prikazani rezultati ispitivanja uticaja novog hemijskog dodatka koji sprečava formiranja leda pri izuzetno niskim temperaturama (do -25 °C) u svežem betonu i omogućuje da se proces očvršćavanja nastavi čim to porast spoljne temperature dozvoli. Ispitivano je dejstvo dodatka na svež i očvrsli beton, bez i sa uticajem niskih temperatura. Prikazani rezultati na uzorcima koji su negovani u vodi temperature 20 °C pokazuju da ispitivani dodatak čak povećava čvrstoću na pritisak očvrslog betona u odnosu na etalon i za više od 10%. Sa ciljem da se ispita dejstvo dodatka u slučaju iznenadnih niskih temperatura simulirane su tri potencijalno realne situacije niskih temperatura. Radi utvrđivanja granica dejstva dodatka svež beton je, kroz ove simulacije, izlagan temperaturama i do -25 °C. U sva tri slučaja beton sa dodacima pokazao je znatno bolje ponašanje i postigao je znatno veće čvrstoće (za preko 100%, a za pojedine režime i za preko 200%). Opitna tela koja su prošla najteži termički režim (3. režim) ispitana su i na upijanje i otpuštanje vode, da bi se utvrdila mera oštećenja strukture usled dejstva mraza i niskih temperatura u periodu očvršćavanja svežeg betona. I ovde su uzorci sa dodatkom pokazali znatno manje upijanje vode, tj. očuvanu strukturu očvrslog betona.",
publisher = "Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije, Beograd",
journal = "Materijali i konstrukcije",
title = "Antifreeze water additives applied to fresh concrete in winter conditions, Primena hemijskog dodatka za sprečavanje zaleđivanja vode u svežem betonu pri betoniranju u zimskim uslovima",
volume = "51",
number = "3",
pages = "24-29",
url = "https://hdl.handle.net/21.15107/rcub_raf_45"
}
