Vpliv distančnikov na kakovost krovnega sloja betona : diplomsko delo

Šadl, Luka (author), Bokan-Bosiljkov, Violeta (mentor), Šajna, Aljoša (comentor)

Armiranobetonske konstrukcije so eden najpogosteje uporabljenih konstrukcijskih sistemov v sodobnem gradbeništvu. Njihova trajnost je med drugim odvisna od kakovosti in debeline krovnega sloja betona, katerega projektirano debelino med izvedbo zagotavljajo distančniki. Ker distančniki ostanejo trajno vgrajeni v krovnem sloju in predstavljajo lokalno diskontinuiteto, lahko vplivajo na njegove transportne lastnosti, vendar je ta vpliv še razmeroma slabo raziskan. Namen diplomske naloge je bil eksperimentalno raziskati vpliv distančnikov različnih materialov in geometrijskih oblik na lokalne transportne lastnosti krovnega sloja betona. Preizkušeni so bili trije tipi distančnikov, vgrajeni v dve različni betonski mešanici, ter referenčni preizkušanci brez distančnikov. Izvedena sta bila preskus zrakoprepustnosti krovnega sloja po SIA 262/1 in preskus globine prodora vode pod pritiskom po SIST EN 12390-8. Rezultati so pokazali, da lahko prisotnost distančnika lokalno poveča prepustnost krovnega sloja, pri čemer je bil obseg vpliva odvisen od vrste distančnika in betonske mešanice. Med preiskanimi distančniki so bile najvišje povprečne vrednosti pri obeh preskusnih metodah izmerjene pri cementnem distančniku D3. Njegov koeficient zrakoprepustnosti kT je bil glede na referenčne preizkušance približno 4-krat večji, pri betonski mešanici 2 pa je bila povprečna globina prodora vode kar 10,6-krat večja. Pri vseh treh preizkušancih te skupine je voda dosegla armaturno palico. Rezultati obeh preskusnih metod kažejo, da območje distančnika lahko predstavlja lokalno prednostno transportno pot skozi krovni sloj. Izbira distančnika zato ni zgolj izvedbena podrobnost, temveč lahko vpliva na lokalno zaščitno sposobnost krovnega sloja in posledično na trajnost armiranobetonske konstrukcije. Zaradi majhnega števila preizkušancev v posamezni skupini pa bi bilo za zanesljivejšo kvantifikacijo vpliva posameznih tipov distančnikov potrebno nadaljnje raziskovanje.

• Language: Slovenian
• Keywords: diplomske naloge, gradbeništvo, distančniki, krovni sloj betona, zrakoprepustnost, globina prodora vode, trajnost armiranega betona
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [L. Šadl]
• Year: 2026
• Number of pages: 1 spletni vir (1 datoteka PDF (IX, 38 str., 3 str. pril.))
• PID: 20.500.12556/RUL-188236
• UDC: 624.012.45:621.882.63(043.2)
• COBISS.SI-ID: 291843843
• Publication date in RUL: 19.09.2026

Secondary language

• Language: English
• Title: Influence of reinforcement spacers on the quality of the concrete cover

Abstract

Reinforced concrete structures are among the most widely used structural systems in modern construction. Their durability depends, among other factors, on the quality and thickness of the concrete cover, the specified thickness of which is ensured during construction by reinforcement spacers. Since spacers remain permanently embedded in the concrete cover and represent a local discontinuity, they may affect its transport properties; however, this influence is still relatively poorly understood. The aim of this diploma thesis was to experimentally investigate the influence of spacers of different materials and geometries on the local transport properties of the concrete cover. Three types of spacers embedded in two different concrete mixtures were tested, together with reference specimens without spacers. Air permeability of the concrete cover was tested in accordance with SIA 262/1, and water penetration under pressure was determined in accordance with SIST EN 12390-8. The results showed that the presence of a spacer can locally increase the permeability of the concrete cover, with the magnitude of the effect depending on the type of spacer and the concrete mixture. Among the tested spacers, the highest average values obtained by both test methods were measured for the cementitious spacer D3. Its air permeability coefficient kT was approximately four times higher than that of the reference specimens, while for concrete mixture 2 the average water penetration depth was as much as 10.6 times greater. In all three specimens in this group, the water reached the reinforcing bar. The results of both test methods indicate that the spacer region may act as a local preferential transport path through the concrete cover. The selection of a spacer should therefore not be regarded merely as a construction detail, as it may affect the local protective performance of the concrete cover and consequently the durability of a reinforced concrete structure. However, due to the small number of specimens in each group, further research is required to provide a more reliable quantification of the influence of individual spacer types.

• Keywords: graduation thesis, civil engineering, reinforcement spacers, concrete cover, air permeability, water penetration depth, durability of reinforced concrete