Vpliv vrste lahkega agregata na lastnosti betona visoke trdnosti : diplomska naloga

Šubic, Nika (author), Saje, Drago (mentor)

Beton visoke trdnosti se ponaša z mnogimi dobrimi lastnostmi a ima tudi negativne, kot je na primer veliko avtogeno krčenje. Le to lahko zmanjšamo z dodajanjem predhodno namočenega lahkega agregata v betonsko mešanico. V diplomski nalogi obravnavamo vpliv različnih lahkih agregatov na tlačne trdnosti in krčenje betona. Opisani so faktorji, od katerih je odvisna učinkovitost lahkega agregata kot notranjega rezervoarja vode. V eksperimentalnem delu diplomske naloge smo primerjali betonske mešanice, ki so vsebovale različni vrsti predhodno namočenega lahkega agregata. Uporabljen je bil naraven lahek agregat Lehnjak frakcij 0-2mm in 2-4mm ter ekspandirana glina Liapor enakih frakcij. Vse štiri betonske mešanice so vsebovale 12% lahkega agregata. Primerjali smo jih s kontrolno mešanico, ki je vsebovala le običajen agregat. Dodajanje predhodno namočenega lahkega agregata v betonsko mešanico se izkaže za ugodno, saj izboljša lastnosti betona. Opazna je tudi razlika med betonskimi mešanicami z dodano različno vrsto in različno zrnavostno strukturo lahkega agregata. Uporaba predhodno namočene ekspandirane gline frakcije 0-2mm, glede na primerljiv beton brez predhodno namočenega lahkega agregata, poveča tlačno trdnost betona in zmanjša njegovo krčenje.

• Language: Slovenian
• Keywords: gradbeništvo, diplomska dela, UNI, B-GR, lahek agregat, notranja nega betona, betoni visoke trdnosti, avtogeno krčenje, krčenje zaradi sušenja
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [N. Šubic]
• Year: 2014
• Number of pages: X, 32 str.
• PID: 20.500.12556/RUL-32466
• UDC: 624.012.4(497.4)(043.2)
• COBISS.SI-ID: 6838625
• Publication date in RUL: 10.07.2015

Secondary language

• Language: English
• Title: The impact of different lightweight aggregates on properties of high strength concrete

Abstract

High strength concrete is known for its many favorable qualities. However it also has some negative characteristics like autogenous shrinkage which can be reduced by adding saturated lightweight aggregate to the concrete mix. The effect of using different types of lightweight aggregate on compressive strength and shrinkage of concrete is discussed in this graduation thesis. Factors influencing the success of internal curing with prewetted lightweight aggregate are described in theoretical part of the thesis and experiments using different kinds of lightweight aggregate were conducted in experimental part. Materials used were natural lightweight aggregate of fractions 0-2 and 2-4 and expanded clay of the same fractions. Four concrete mixes containing 12% of different lightweight aggregates were compared to a comparable concrete mix without lightweight aggregate. It appears that the use of prewetted lightweight aggregate improves the performance of high strength concrete; however the variation of results is noticeable. The type and grading of lightweight aggregate we add to the cement mix has an influence on the effectiveness of internal curing. In comparison with a similar concrete without prewetted lightweight aggregate, adding prewetted expanded clay of fraction 0-2mm increases compressive strength and decreases autogenous shrinkage of high strength concrete.

• Keywords: graduation thesis, civil engineering, lightweight aggregate, internal curing of concrete, high performance concretes, autogenous shrinkage, drying shrinkage