Vpliv cementnih dodatkov na korozijske procese jekla v zelenih betonih : magistrsko delo

Milost, Egon (author), Bokan-Bosiljkov, Violeta (mentor)

V magistrskem delu je obravnavano področje uporabe cementnih dodatkov v zelenih betonih in njihov vpliv na lastnosti strjene cementne matrice in na korozijo vgrajenega jekla. Cementi s tako modificirano sestavo dosegajo večji ekonomski učinek zaradi boljšega izkoristka surovin in energije, potrebne za njegovo izdelavo. V okviru preiskav smo v laboratoriju posušili in mehansko obdelali osnovne materiale za pripravo cementov, ki smo jih nato sestavili v želenem razmerju in zmleli v šest različnih cementov. Cementom smo določili specifično površino, gostoto, kemično sestavo in vsebnost kloridov ter iz njih pripravili maltne vzorce za preiskave. Po končani osemindvajsetdnevni negi smo na vzorcih določili upogibne in tlačne trdnosti ter statični modul elastičnosti. V nadaljevanju smo vzorce izpostavljali pospešeni koroziji s kloridi in na njih opravljali elektrokemijske meritve po treh različnih metodah za spremljanje in detektiranje sprememb v korozijskem stanju jekla v betonu. S potenciostatsko metodo smo pri povečanem potencialu spremljali gostote tokov po spremenjeni standardni metodi. Z elektrokemijsko impedančno spektroskopijo pa smo v 22 tedenskem obdobju spremljali korozijsko aktivnost pri vzorcih potopljenih v raztopino kloridnih ionov oz. pri vzorcih, ki smo jih ciklično močili in sušili. Določili smo tudi kapilarno vpojnost in poroznost vzorcev z živosrebrno porozimetrijo. Vse vzorce smo po končanih preiskavah porušili in opravili vizualni pregled površine armature. Ciklično močenim in sušenim vzorcem preiskovanim z elektrokemijsko impedančno spektroskopijo smo po koncu izpostavljanja določili še vsebnost kislinotopnih in vodotopnih kloridov v krovnem sloju malte. Na koncu smo na osnovi vizualnih pregledov in rezultatov elektrokemijskih meritev ocenili primernost in ovrednotili zanesljivost uporabljenih metod za spremljanje in detektiranje sprememb v korozijskem stanju jekla v betonu.

• Language: Slovenian
• Keywords: gradbeništvo, magistrska dela, cementni dodatki, korozija jekla, nadomestni cementni materiali, zeleni beton, malta, elektrokemijske tehnike, elektrokemijska impedančna spektroskopija
• Work type: Master's thesis
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [E. Milost]
• Year: 2016
• Number of pages: XV, 83 str.
• PID: 20.500.12556/RUL-85778
• UDC: 624.01:691.54(043)
• COBISS.SI-ID: 7617377
• Publication date in RUL: 27.09.2016

MILOST, Egon, 2016, Vpliv cementnih dodatkov na korozijske procese jekla v zelenih betonih : magistrsko delo [online]. Master’s thesis. Ljubljana : E. Milost. [Accessed 16 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=85778

Secondary language

• Language: English
• Title: Effect of cementitious additives on corrosion processes of steel in green concretes

Abstract

In this thesis the field of supplementary cementitious materials (SCM) for so-called green concretes, and their influence on the properties of the hardened cement matrix and the corrosion of embedded steel, is discussed. Cements with such a modified composition achieve a greater economic effect due to better utilization of the raw materials and energy needed for their manufacture. During the performed investigations, the basic materials for the production of cement were first dried and mechanically treated. They were then mixed together in the selected proportions and ground into six different cements. After the specific surface area, density, chemical composition, and chlorides content in the cements had been determined, mortar samples for testing were prepared. After a curing period of twenty-eight days the flexural strength, compressive strength, and static modulus of elasticity of the test specimens were determined. They were then exposed to accelerated chloride induced corrosion, and electrochemical measurements were performed by means of three different methods for monitoring and detecting changes in the state of corrosion of steel in concrete. With potentiostatic method the corrosion current densities at increased potential were followed according to adopted standard method. With electrochemical impedance spectroscopy the corrosion activity in 22-week period on samples immersed into chloride solution and on samples that were cyclically exposed to wet and dry conditions was measured. The resistance to capillary absorption and the porosity of the samples were determined. After completion of the investigations, the samples were longitudinally split into two pieces, and a visual inspection of the reinforcement surface was carried out. The acid-soluble and water-soluble chloride contents were determined for the specimens investigated according to the third method. Finally, the suitability and reliability of the methods used for monitoring and detecting changes in the state of corrosion of steel in concrete, based on visual inspection and the results of electrochemical measurements, were assessed.

• Keywords: civil engineering, master of science thesis, cementitious additives, SCM, corrosion of steel, green concrete, mortar, electrochemical techniques, electrochemical impedance spectroscopy