Title Samozbijajući beton s recikliranom gumom u konstrukcijskim elementima
Title (english) Self-compacting rubberized concrete in structural members
Author Robert Bušić
Mentor Ivana Miličević (mentor)
Mentor Tanja Kalman Šipoš (komentor)
Committee member Ivica Guljaš (predsjednik povjerenstva)
Committee member Davorin Penava (član povjerenstva)
Committee member Ivana Miličević (član povjerenstva)
Granter Josip Juraj Strossmayer University of Osijek Faculty of Civil Engineering and Architecture Osijek Osijek
Defense date and country 2022, Croatia
Scientific / art field, discipline and subdiscipline TECHNICAL SCIENCES Civil Engineering
Universal decimal classification (UDC ) 69 - Building (construction) trade. Building materials. Building practice and procedure
Abstract U svijetu se godišnje proizvede približno jedna milijarda otpadnih guma. Navedeni se broj iz godine u godinu povećava, a samo se 2 % otpadnih guma kao reciklirani materijal koristi u građevinskom sektoru. Uključivanje otpadne gume u građevinsku industriju predstavlja ekološki prihvatljivo rješenje za zbrinjavanje otpadne gume koje promovira održivu gradnju i potiče koncept održive proizvodnje. Detaljnim pregledom literature utvrđene su prednosti korištenja samozbijajućeg betona s recikliranom gumom u odnosu na obični beton s recikliranom gumom te je zaključeno da postojeća znanstvena istraživanja u najvećoj mjeri obuhvaćaju ispitivanja mehaničkih svojstava betona s gumom. Istraživanja termičkih svojstava, svojstava trajnosti te konstrukcijskih elemenata izrađenih od samozbijajućeg betona s recikliranom gumom nisu značajno zastupljena u dostupnoj literaturi, što predstavlja potencijal za buduća eksperimentalna istraživanja.
Glavni cilj ovog istraživanja bio je utvrditi utjecaj reciklirane gume na mehanička i termička svojstva, svojstva trajnosti, parametre mehanike loma i mikrostrukturu samozbijajućeg betona te dokazati mogućnost primjene reciklirane gume u nosivim armiranobetonskim gredama zadovoljavajuće mehaničke otpornosti i stabilnosti te poboljšanih svojstava trajnosti. Kako bi se postigao zadani cilj, u prvom koraku provedena su preliminarna eksperimentalna ispitivanja samozbijajućega betona s recikliranom gumom s ciljem definiranja optimalnog sastava betonske mješavine, materijala koji će reciklirana guma zamijeniti, udjela reciklirane gume u sastavu betonsku mješavine te potrebi prethodnoga tretiranja reciklirane gume. U idućem koraku, s ciljem odabira optimalnih mješavina, izrađena je 21 mješavina samozbijajućeg betona s različitim postotnim udjelima reciklirane gume kao djelomične zamjene sitnoga agregata i silicijske prašine kao djelomične zamjene cementu te su provedena ispitivanja svojstava samozbijajućega betona u svježem i očvrsnulom stanju. Provedena su i dodatna eksperimentalna istraživanja ponašanja samozbijajućeg betona s recikliranom gumom pri lomu promatranjem osnovnih parametara mehanike loma. Nakon toga provedena su eksperimentalna ispitivanja odabranih optimalnih mješavina samozbijajućega betona s recikliranom gumom na razini materijala i na razini konstrukcijskih elemenata. Na razini materijala dodatno su ispitana svojstva trajnosti i termička svojstva optimalnih mješavina samozbijajućeg betona s recikliranom gumom te struktura i veza na sučeljku cementnog kamena i prirodnog agregata, tj. reciklirane gume pomoću pretražnoga elektronskog mikroskopa. Na razini konstrukcijskih elemenata ispitano je 12 greda, po tri od svake odabrane betonske mješavine.
Na temelju eksperimentalnih rezultata dokazano je da se postotni udjeli reciklirane gume od 10 i 15 % mogu koristiti u nosivim armiranobetonskim elementima bez dodatnih ograničenja vezanih uz svojstva trajnosti, termička svojstava i svojstava mehanike loma. Nadalje, dokazano je da reciklirana guma doprinosi poboljšanju svojstava trajnosti armiranobetonskih greda te da je nosivost armiranobetonskih greda s recikliranom gumom slična ili jednaka nosivosti armiranobetonskih greda bez reciklirane gume.
Abstract (english) Approximately 1 billion waste tires are produced annually worldwide. This number is increasing from year to year and only 2 % of waste tires are used as recycled material in the construction sector. The inclusion of waste rubber in the construction industry is an environmentally friendly solution for the disposal of waste rubber which promotes sustainable construction and encourages the concept of sustainable production. With detailed literature overview, the advantages of using self-compacting concrete with recycled rubber over ordinary concrete with recycled rubber were identified and conclusion was made that existing scientific research in the majority includes investigation of the mechanical properties of concrete with rubber. Investigations of thermal properties, durability properties and structural elements made of self-compacting concrete with recycled rubber are quite unrepresented in the available literature, which represents the potential for future experimental research.
The main goal of this research was to determine the influence of recycled rubber on mechanical, thermal and durability properties, fracture mechanics parameters and microstructure of self-compacting concrete and to prove the possibility of using recycled rubber in load-bearing reinforced concrete beams with satisfactory mechanical resistance and stability and improved durability properties. To achieve the set goal, several steps have been taken. In the first step, preliminary experimental testing of self-compacting concrete with recycled rubber was performed to define the optimal composition of the self-compacting concrete mixture, the replaced material, the proportion of recycled rubber in the self-compacting concrete mixture and the need for pre-treatment of recycled rubber.
In the next step, in order to select the optimal mixtures, 21 mixtures of self-compacting concrete with different percentages of recycled rubber as partial replacement of fine aggregate and silica fume as a partial replacement of cement were made and investigation of the self-compacting concrete fresh and hardened state properties were performed. Additional experimental investigation of the fracture behavior of self-compacting concrete with recycled rubber was performed by observing the basic parameters of fracture mechanics. In final two steps, experimental tests of selected optimal mixtures of self-compacting concrete with recycled rubber at the level of material and at the level of structural elements were then performed. At the level of material, the durability and thermal properties of optimal self-compacting rubberized concrete mixtures were examined. Additionally, bond between cement paste and natural aggregate, i.e. recycled rubber was examined with scanning electron microscope. At the level of structural elements, 12 beams were tested, three from each selected concrete mix.
Based on experimental results, it has been proven that the percentages of recycled rubber of 10 % and 15 % can be used in load-bearing reinforced concrete elements without additional restrictions related to durability, thermal and fracture properties. Furthermore, it has been proven that recycled rubber contributes to improving the durability properties of reinforced concrete beams and that the load-bearing capacity of reinforced concrete beams with recycled rubber is similar or equal to the load-bearing capacity of reinforced concrete beams without recycled rubber.
Keywords
samozbijajući beton
reciklirana guma
svojstva u svježem i očvrsnulom stanju
mehanička svojstva
svojstva trajnosti
termička svojstva
mehanika loma
armiranobetonske grede
Keywords (english)
self-compacting concrete
recycled rubber
fresh and hardened properties
mechanical properties
durability properties
thermal properties
fracture mechanics
reinforced concrete beams
Language croatian
URN:NBN urn:nbn:hr:133:599915
Promotion 2022
Study programme Title: Postgraduate university study program in civil engineering Study programme type: university Study level: postgraduate Academic / professional title: doktor/doktorica tehničkih znanosti u polju građevinarstva (doktor/doktorica tehničkih znanosti u polju građevinarstva)
Type of resource Text
File origin Born digital
Access conditions Open access
Terms of use
Created on 2022-03-03 11:59:04