UNIVERSITY OF NIS

FACULTY OF CIVIL ENGINEERING AND ARCHITECTURE

in cooperation with

UNIVERSITY OF NOVI SAD

FACULTY OF TECHNICAL SCIENCES

DEPARTMENT OF CIVIL ENGINEERING AND GEODESY

UNIVERZITET U NIŠU

GRAĐEVINSKO-ARHITEKTONSKI FAKULTET

u saradnji sa

FAKULTETOM TEHNIČKIH NAUKA U NOVOM SADU

DEPARTMAN ZA GRAĐEVINARSTVO I GEODEZIJU

V INTERNATIONAL SYMPOSIUM

FOR STUDENTS OF DOCTORAL STUDIES IN THE FIELDS OF CIVIL ENGINEERING,

ARCHITECTURE AND ENVIRONMENTAL

PROTECTION

V MEĐUNARODNI SIMPOZIJUM

STUDENATA DOKTORSKIH STUDIJA IZ OBLASTI GRAĐEVINARSTVA,

ARHITEKTURE I ZAŠTITE ŽIVOTNE SREDINE

PROCEEDINGS Nis, Serbia, 24 – 25 October 2019

ZBORNIK RADOVA Niš, Srbija, 24 – 25. oktobar 2019.

BOOK TITLE:

V International Symposium for Students of Doctoral Studies in the Fields of Civil Engineering,

Architecture and Environmental Protection PhIDAC 2019 – Proceedings

PUBLISHER:

Faculty of Civil Engineering and Architecture, University of Nis, 2019.

EDITORS:

Prof. Zoran Grdic

Assoc. Prof. Gordana Toplicic-Curcic

Assis. Prof. Nenad Ristic

Assis. Prof. Vuk Milosevic

TECHNICAL EDITOR:

Assis. Prof. Nenad Ristic

PRINTING:

Faculty of Civil Engineering and Architecture, University of Nis, 2019

EDITION:

100 copies

ISBN 978-86-88601-43-6

CIP - Каталогизација у публикацији

Народна библиотека Србије, Београд

624(082)(0.034.2)

72(082)(0.034.2)

502/504(082)(0.034.2)

INTERNATIONAL Symposium for Students of Doctoral Studies in the Fields of Civil Engineering,

Architecture and Environmental Protection (5 ; 2019 ; Niš)

Proceedings [Elektronski izvor] = Zbornik radova / V International Symposium for Students of

Doctoral Studies in the Fields of Civil Engineering, Architecture and Environmental Protection, Nis,

Serbia, 24-25 October 2019 = V Međunarodni simpozijum studenata doktorskih studija iz oblasti

građevinarstva, arhitekture i zaštite životne sredine, PhIDAC 2019, Niš, Srbija, 24-25. oktobar 2019. ;

[organizer] University of Nis, Faculty of Civil Engineering and Architecture in cooperation with

University of Novi Sad Faculty of Technical Sciences Department of Civil Engineering and Geodesy

; [organizatori] Univerzitet u Nišu Građevinsko-arhitektonski fakultet u saradnji sa Fakultetom

tehničkih nauka u Novom Sadu Departman za građevinarstvo i geodeziju ; [editors Zoran Grdic ... [et

al.]]. - Nis : Faculty of Civil Engineering and Architecture, University, 2019 (Nis : Faculty of Civil

Engineering and Architecture, University). - 1 USB fleš memorija ; 1 x 3 x 6 cm

Sistemski zahtevi: Nisu navedeni. - Nasl. sa naslovne strane dokumenta. - Tiraž 100. - Bibliografija

uz svaki rad. - Rezimei.

ISBN 978-86-88601-43-6

а) Грађевинарство -- Зборници б) Архитектура -- Зборници в) Животна средина -- Зборници

COBISS.SR-ID 280416780

SCIENTIFIC COMMITTEE:

Prof. Zoran Grdic, Serbia (Chairman)

Prof. Vlastimir Radonjanin, Serbia (Co-Chairman)

Prof. Gordana Toplicic-Curcic, Serbia

Prof. Mirjana Malesev, Serbia

Prof. Emeritus Radomir Folic, Serbia

Prof. Nаdja Kurtovic-Folic, Serbia

Prof. Bosko Stevanovic, Serbia

Prof. Dimitrije Zakic, Serbia

Prof. Miroslav Besevic, Serbia

Prof. Dragan Milasinovic, Serbia

Prof. Milos Knezevic, Montenegro

Prof. Radomir Zejak, Montenegro

Prof. Emeritus Dubravka Bjegovic, Croatia

Prof. Ivanka Netinger Grubesa, Croatia

Prof. Barbara Karleusa, Croatia

Prof. Meri Cvetkovska, North Macedonia

Prof. Goran Markovski, North Macedonia

Prof. Aneta Hristova Popovska, North Macedonia

Prof. Petar Filkov, Bulgaria

Prof. Anca Constantin, Romania

Prof. Emina Hadzic, Bosnia and Herzegovina

Prof. Damir Zenunovic, Bosnia and Herzegovina

Prof. Dragoslav Stojic, Serbia

Prof. Petar Мitkovic, Serbia

Prof. Marina Mijalkovic, Serbia

Prof. Slavisa Trajkovic, Serbia

Prof. Ljiljana Vasilevska, Serbia

Prof. Zoran Bonic, Serbia

Prof. Miomir Vasov, Serbia

Prof. Danica Stankovic, Serbia

Prof. Milan Gocic, Serbia

Ass. Prof. Dejan Vasovic, Serbia

Ass. Prof. Slobodan Rankovic, Serbia

ORGANIZATION BOARD:

Assis. Prof. Nenad Ristic (Chairman)

Assis. Prof. Ivan Lukic (Co-Chairman)

Assis. Prof. Vuk Milosevic

Dusan Grdic, assistant

PhD Hristina Krstic, assistant

Milica Igic, assistant

Goran Stevanovic,

Aleksandar Vasilic

ORGANIZER:

UNIVERSITY OF NIS

FACULTY OF CIVIL ENGINEERING AND ARCHITECTURE

CO-ORGANIZER:

UNIVERSITY OF NOVI SAD

FACULTY OF TECHNICAL SCIENCES

DEPARTMENT OF CIVIL ENGINEERING AND GEODESY

DONATORS:

CRH SRBIJA

PUT-INŽENJERING D.O.O. NIŠ

JUGO-IMPEX E.E.R. D.O.O. NIŠ

SIKA SRBIJA D.O.O.

ADING D.O.O. BEOGRAD

ARHIBET D.O.O. NIŠ

BRZMIN D.O.O. BRZEĆE

KUBIKTRANS PLUS D.O.O. PIROT

MARKO TRANS CARGO D.O.O. BEOGRAD

PROJEKTINŽENJERING TIM D.O.O. NIŠ

PTGP SABA BELČA D.O.O. PREŠEVO

ŠILO-PROM D.O.O. BELOTINAC

SZR TASIĆ-KOP PROKUPLJE

VODOGRADNJA D.O.O. PUKOVAC

VIZUS D.O.O. NIŠ

PREVOZKOP ALEKSANDROVO

TOURIST ORGANIZATION OF NIS

EDITORAL NOTE:

The Faculty of Civil engineering and Architecture of University of Nis organizes the Fifth International

Symposium of Doctoral Studies’ Students in the fields of Civil Engineering, Architecture and

Environmental Protection “PhIDAC 2019”.

The first Symposium of the Doctoral Studies’ Students “PhIDAC 2009”, held in September 2009 in Nis,

confirmed the expectations of Prof. Slavisa Trajkovic and Professor emeritus Radomir Folic, the founders

of this symposium, that the two-day meetings of the students of Doctoral studies and their professors

would be of invaluable use both for young researchers and their tutors. Namely, a great number of

published and presented papers, as well as open discussion on the quality of paper, directions in further

researches and relationships between doctoral students and tutors demonstrated that the Symposium

fulfilled the expectations of the participants and that the organization of new meetings should be

continued.

At the Second Symposium “PhIDAC 2010” held in Novi Sad, the symposium programme was expanded,

i.e. the field of environmental protection was also introduced as the third thematic field with the

expectation that this multidisciplinary area should be more closely introduced to young researches in the

fields of civil engineering and architecture.

The organizers of the Third Symposium “PhIDAC 2011”, also held in Novi Sad, decided that the

symposium should be international and thus they opened new possibilities for affirmation and

development of young researches from Serbia, as well as of their colleagues from the Balkans.

There were 66 papers dealing with topics in the fields of civil engineering, architecture and environment

protection that were submitted for the fourth international symposium of students of doctoral studies

“PhIDAC 2012”. The papers covered a wide range of scientific topics. All the papers were reviewed. On

the basis of the reviews, it was concluded that the young researchers provided a significant contribution

to the development of scientific thinking.

Members of the international scientific committee actively participated in the preparation of the

symposium and reviewing of the papers. For this symposium too, the proceedings including papers in

English and Serbian were included, which provides better and more productive communication and

exchange of experience with the colleagues from abroad.

We would like to thank all the authors and co-authors of the papers and their mentors, and it is our wish

that the young researchers would continue their successful careers and persist in realization of the goals

they have set.

Nis, October 2019 Editors

THE CONTENT:

PLENARY LECTURE / PLENARNO PREDAVANJE

Bakatsaki Maria 10

THE ROLE OF EMOTIONAL AND SOCIAL INTELLIGENCE IN HUMANITARIAN RELIEF

PAPERS IN ENGLISH LANGUAGE / RADOVI NA ENGLESKOM JEZIKU

SESSION ARCHITECTURE / OBLAST ARHITEKTURA

1. Mitrović Tanja, Topalić Marković Jovana 23

CHILDREN'S DECISION MAKING INVOLVEMENT IN URBAN PLANNING

2. Donchev Vasil 31

LATE ANTIQUITY AND MEDIEVAL FORTRESS RUSOKASTRO –

PROSPECTS FOR CONSERVATION, RESTORATION AND ADAPTATION AS CULTURAL

HERITAGE TOURISM SITE

3. Simovic Milica, Lovric Petar 38

THE NEW PARADIGM ON MOBILITY OF FLOATING ARCHITECTURE

4. Ivanova Blagovesta 46

THE ARCHITECTURAL FACADE AS AN ART DECOR IN SOFIA AND PLOVDIV

5. Kocić Dragana, Stefanović Violeta 54

THE SOCIALIST MEMORY AND POST-SOCIALIST PROCESSING OF THE IDENTITY OF THE

CENTRAL COMMITTEE BUILDING

6. Rancic Aleksandra, Mitkovic Petar, Stankovic Danica 62

NATURAL SPACES IN PRESCHOOL FACILITIES - METHODS TO IMPROVE THE QUALITY OF

EARLY CARE ENVIRONMENT

7. Ivanova Alexandra, Nikolov Nikolai 70

VISUAL ARTS IN THE URBAN SPATIAL ENVIRONMENT

8. Jordanović Marina, Momčilović Petronijević Ana, Vasić Milanka, Jevremović Ljiljana 77

NATIONAL CONSTRUCTION IN SERBIA ON THE CASE OF RURAL ARCHITECTURE IN THE

SERVICE OF RURAL TOURISM

9. Kuseva Kalina 85

METHODOLOGICAL AND PLANNING ASPECTS OF MANAGEMENT OF URBAN DEVELOPMENT.

CITY PLANNING AND MANAGEMENT DURING AND AFTER DISASTERS AND ACCIDENTS

10. Jevremovic Ljiljana, Stanojevic Ana, Turnsek Branko, Jordanovic Marina, Vasic Milanka, Djordjevic Isidora

93

TESTING THE SUSTAINABILITY AND VALIDITY OF INSTALLING PHOTOVOLTAIC PANELS ON

THE ROOFTOPS OF INDUSTRIAL BUILDINGS

11. Marinova Ivanka 101

POTENTIAL OF ABANDONED INNER-CITY INDUSTRIAL AREAS AS A SUSTAINABLE

ARCHITECTURAL AND URBAN DEVELOPMENT RESOURCE

12. Stanojević Ana, Jevremović Ljiljana, Turnšek Branko, Stanković Danica, Jordanović Marina, Vasić Milanka,

Đorđević Isidora 109

THE QUALITY OF OUTDOOR URBAN SPACES - CASE STUDY OF THE KINDERGARTENS IN THE

CITY OF NIS

13. Krstić Hristina, Dib Antoine, Cvetković Mila 117

HOUSE DESIGN: MAKING THE COMPOSITION BY DECOMPOSING

14. Ranđelović Dušan, Vasov Miomir, Savić Jelena, Ćurčić Aleksandra 124

APPLICATION OF GREEN ROOF AS A MODEL FOR IMPROVING THE ENERGY PERFORMANCE

OF ELEMENTARY SCHOOLS

15. Vunjak Danilo, Krklješ Milena 132

CULTURAL IDENTITY OF THE SERBIAN CITY

16. Stankovic Bojan, Mitkovic Mihajlo, Mitkovic Petar 139

SMART CITIES TODAY AND CITIES OF THE FUTURE IN THE VISIONS OF ARCHITECTS:

MASDAR, ABU DHABI (UAE)

17. Cvetanović Aleksandra, Keković Aleksandar, Stanković Danica 146

THE BIOPHILIC APPROACH IN INTERIOR DESIGN:

RECONNECTING INDOORS WITH NATURE

18. Ćurčić Aleksandra, Jovanović Goran, Keković Aleksandar, Ranđelović Dušan 154

SUSTAINABLE INTERIOR DESIGN - USE OF ECO-FRIENDLY AND RECYCLED MATERIALS

19. Sas Maria Alexandra 162

CULTURAL HERITAGE REVITALIZATION.

ITEM CASE HALLER CASTEL IN ROMANIA.

20. Kićanović Jelena, Dubljević Sanja 172

INTEGRATION OF BIM TECHNOLOGY AND AUGMENTED REALITY (AR) DURING PROJECT

DESIGN AND CONSTRUCTION

21. Gjorgjevska Violeta 179

FROM ABANDONED URBAN FRAGMENTS INTO ECOLOGICAL LANDSCAPE ATTRACTION

22. Milkova Darena 186

IRRATIONALITY IN THE CONTEMPORARY URBANIZATION

23. Vasilevska Magdalena, Mitković Petar 191

THE BLUE-GREEN APPROACH: NEW SOLUTIONS FOR URBAN PLANNING AND DESIGN

24. Veljković Sandra, Ćurčić Aleksandra, Mitić Vojislav, Topličić-Ćurčić Gordana 199

OLED LIGHT SOURCES IN ARCHITECTURE

25. Tošić Zlata, Momčilović Petronijević Ana 206

PROPOSAL FOR REVITALIZATION OF THE NATIONAL WEIFERT BREWER

26. Cvetković Mila, Tanić Milan 214

REVITALIZATION OF HISTORICAL ARCHITECTURE: THE METHODOLOGY OF DESIGN AND

ALTERATION TYPES

SESSION CIVIL ENGINEERING AND ENVIRONMENTAL PROTECTION /

OBLAST GRAĐEVINARSTVO I ZAŠTITA ŽIVOTNE SREDINE

27. Topalić Marković Jovana, Mučenski Vladimir, Mitrović Tanja 225

MODIFIED RISK STRUCTURE FOR PLANNING AND DESIGNING OF WASTEWATER TREATMENT

PLANTS

28. Džanić Zlatko, Hrasnica Mustafa, Medić Senad 232

THE CAPACITY OF SQUAT SHEAR WALLS

29. Veselinović Dragana 240

BIM TECHNOLOGY, GENERATIVE DESIGN AND ARTIFICIAL INTELLIGENCE - APPLICATION IN

CONSTRUCTION PROJECT MANAGEMENT

30. Živković Lazar, Živković Srđan, Ristić Jovan, Marinković Nemanja 246

POSSIBILITIES OF APPLICATION HISTAR STEEL IN CIVIL ENGINEERING

31. Marinković Nemanja, Davidović Nebojša, Romić Nikola, Stanković Branimir, Živković Lazar 253

POSSIBILITY ANALISIS FOR REUSING RECYCLED MATERIALS FROM BUILDING DEMOLITION

WASTE IN GEOTECHNICS

32. Milić Miloš, Vacev Todor, Nešović Ivan, Zorić Andrija, Romić Nikola, Stanković Branimir 260

APPLICATION OF STEEL-TIMBER COMPOSITE STRUCTURES

TO FLOOR CONSTRUCTION

33. Jovanović Jelena, Matejević Biljana, Dimitrijević Jelena 267

TECHNOLOGY AND ORGANIZATION OF EXECUTION OF WORKS ON REPAIR OF TECHNICAL

PASSENGER STATION ZEMUN

34. Stankovic Sandra, Vasovic Dejan, Trajkovic Slavisa 275

SOLVING THE CHALLENGES IMPOSED BY EXTREME HYDROLOGICAL PHENOMENA: CASE

STUDY ON SELECTED WATER SUPPLY SYSTEMS IN SOUTHEASTERN SERBIA

35. Grebović Marko, Sinđić Grebović Radmila 280

GENERATING CLIMATIC DATA FOR CALCULATION OF ANNUAL ENERGY USE OF BUILDINGS

36. Nešović Ivan, Mijalković Marina, Karamarković Jugoslav, Đorić-Veljković Snežana, Milić Miloš, Vacev

Todor 288

FIRE RESISTANCE DESIGN OF STEEL STRUCTURES USING EUROCODE

37. Aškrabić Marina, Stevanović Boško, Zakić Dimitrije, Savić Aleksandar, Topličić-Ćurčić Gordana 296

EFFECTS OF FINE CRUSHED CERAMIC WASTE ADDITION TO LIME - BASED COATING FOR

RESTORATION OF HISTORICAL BUILDINGS

38. Grdić Dušan, Ristić Nenad, Topličić - Ćurčić Gordana, Krstić Dejan 304

PRACTICAL USE OF WASTE CRT GLASS FOR MAKING OF CONCRETE PREFABRICATED

PRODUCTS

39. Bijeljić Jelena, Ristić Nenad, Topličić – Ćurčić Gordana, Grdić Zoran, Grdić Dušan, Krstić Dejan 312

FREEZE – THAW RESISTANCE OF GEOPOLYMER MORTAR BASED ON INDUSTRIAL BY-

PRODUCTS

40. Milošević Vuk, Kostić Dragan, Milošević Jelena 319

MEMBRANE FORCES OF TYPICAL TENSILE MEMBRANE STRUCTURES UNDER POINT LOAD

ACTION

41. Miljan Šunjević, Darko Reba, Mirjana Vojinović Miloradov, Boris Obrovski, Vladimir Rajs 327

SENSORS APPLICATION FOR MONITORING PM POLLUTION ON CONSTRUCTION SITES IN

NOVI SAD

RADOVI NA SRPSKOM JEZIKU / PAPERS IN SERBIAN LANGUAGE

OBLAST ARHITEKTURA / SESSION ARCHITECTURE

42. Pličanić Maja 333

THE PRINCIPLE OF REVERSIBILITY IN THE MODERN APPROACH TO THE PROTECTION OF

THE INDUSTRIAL HERITAGE BUILDINGS - INDUSTRY VS. INDUSTRY

43. Janković Sanja, Jovanović Goran 343

PASSIVE CONSTRUCTION FEATURES AS PARAMETERS AND METHODS OF RATIONALIZATION

IN ARCHITECTURAL DESIGN

44. Stevanović Slaven 351

THE THEO-ANTHROPOLOGICAL PARADIGM OF ARCHITECTURE

45. Dmitrović Manojlović Jelena 358

ARCHITECTURAL MEANINGS AS A CONSTITUTIVE PART OF AN ARCHITECTURAL MENTAL

IMAGE

46. Petković Jovana 364

МULTI-FAMILY HOUSING INDIVIDUALIZATION CONCEPT IN THE DOUBLE-TRACT UNITS

OBLAST GRAĐEVINARSTVO I ZAŠTITA ŽIVOTNE SREDINE /

SESSION CIVIL ENGINEERING AND ENVIRONMENTAL PROTECTION

47. Anđelić Lazar, Prodanović Dušan, Jaćimović Nenad, Ivetić Damjan 374

EFEKTI PRIMENE SAVREMENIH SISTEMA ZA SMANJENJE KIŠNOG OTICAJA NA PRIMERU

NASELJA VOJLOVICA, PANČEVO

48. Živković Lazar, Petrović Žarko, Blagojević Predrag, Bonić Zoran, Ristić Jovan 393

ДИМЕНЗИОНИСАЊЕ ПРАВОУГАОНИХ АРМИРАНОБЕТОНСКИХ ПРЕСЕКА СА

КОМПОЗИТНОМ GFRP АРМАТУРОМ

49. Igić Aleksandra, Zdravković Slavko 401

ПРИНЦИПИ ДИНАМИКЕ

50. Marković Vladimir 409

THE STRAW AS NATURAL AND ECOLOGICAL BUILDING MATERIAL

51. Cvetković Milena 417

ZAGAĐIVANJE VODA I MERE ZA ZAŠTITU VODA

52. Obrovski Boris, Mihajlović Ivana, Bajić Jovan, Vojinović-Miloradov Mirjana, Batinić Branislav, Šunjević

Miljan, Rajs Vladimir 425

KOLORIMETRISKI SENZOR ZA ODREĐIVANJE KVALITETA RAZLIČITIH VODNIH TELA

53. Dragojević Marko 431

ANALIZA I KLASIFIKACIJA UGOVORA O GRAĐENJU I SPECIFIČNOSTI FIDIC-OVIH USLOVA

UGOVORA

54. Stojić Nikola, Marković Nemanja, Grdić Zoran 439

OŠTEĆENJA BETONKIH MOSTOVA

55. Ristić Jovan, Blagojević Predrag, Mladenović Biljana, Živković Lazar 446

OPTIMALNA VREDNOST DILATACIJE U ARMATURI ZA DIMENZIONISANJE PRAVOUGAONIH

PRESEKA U SKLADU SA EC2

56. Mišković Zoran, Savatović Siniša 453

УПОРЕДНА АНАЛИЗА МЕРЕНИХ И РАЧУНСКИХ МОДАЛНИХ ОБЛИКА МОДЕЛА ЧЕЛИЧНОГ

НОСАЧА

V INTERNATIONAL SYMPOSIUM FOR STUDENTS OF DOCTORAL STUDIES IN THE FIELDS OF CIVIL ENGINEERING, ARCHITECTURE AND ENVIRONMENTAL PROTECTION

-312-

Jelena Bijeljić1

Nenad Ristić2

Gordana Topličić – Ćurčić3

Zoran Grdić4

Dušan Grdić5

Dejan Krstić6

FREEZE – THAW RESISTANCE OF GEOPOLYMER MORTAR BASED

ON INDUSTRIAL BY-PRODUCTS

Abstract: This paper investigated characteristics of geopolymer mortar mixes based on fly ash with

admixture of aluminosilicate material – red mud. Four geopolymer mortar mixes were made with fly ash

and red mud and one cement mixture. Mixes based on fly ash were made with different share of red mud -

5 % tо 20 % of mass.

The goal of this research was to determine the strengths of geopolymer mortar at the age of 3, 7, 28,

56 and 90 days, and to determine behavior of mortar mixes of such composition after exposure to 25

cycles of the freeze-thaw test. The mixes were cured under the same ambient conditions and had the same

water/binder and binder/aggregate ratios.

Кey words: geopolymer mortar, fly ash, red mud, freeze-thaw cycles, mechnical properties

1. INTRODUCTION

In the recent years, environment-friendly building materials have been in the focus. Geopolymers are

composite materials whose characteristics are similar to the traditional cement mixes [1]. Geopolymers

are alkali-activated aluminosilicate materials with a much smaller CO2 footprint than traditional Portland

cements, and display good mechanical and durability properties. Geopolymers are mostly based on the

waste byproducts, most frequently of industrial production [2].

Until now, a large number of author research potential use of different byproducts for making of

geopolymer mortars, whereby various physical, mechanical and other characteristics were tested. The

research included potential use of red mud as a partial substitution for fly ash, blast furnace slag,

metakaolin etc. and its effect on physical and mechanical strengths of geopolymer mortar. Jian He et al

investigated two geopolymer mixtures synthesized from two different raw materials: metakaolin and the

mixture of red mud (RM) and fly ash (FA). They researched microstructure, curing duration, and

mechanical properties of the resulting geopolymer [3]. M. Zang et al. investigated geopolymer mixtures

when synthesized from RM and three FA sources to physical and chemical properties, nominal Si/Al and

1 Teaching assistant, College of applied technical science Niš, Aleksandra Medvedeva 20, neimar.jelena@gmail.com: 2 Assistant professor, University of Niš, Faculty of Civil Engineering and Arhitecture Niš, Aleksandra Medvedeva 14, Niš,

nenad.ristic@gaf.ni.ac.rs, 3 Associate professor, University of Niš, Faculty of Civil Engineering and Arhitecture Niš, Aleksandra Medvedeva 14, Niš,

Serbia, gordana.toplicic.curcic@gaf.ni.ac.rs 4 Full professor, University of Niš, Faculty of Civil Engineering and Arhitecture Niš, Aleksandra Medvedeva 14, Niš, :

zoran.grdic@gaf.ni.ac.rs 5 MScCE, Faculty of Civil Engineering and Architecture, University of Niš, Aleksandra Medvedeva 14, Niš, Serbia,

dusan.grdic@gaf.ni.ac.rs 6 Grad. Civ. Eng., Faculty of Civil Enginnering and Architecture, University of Niš, Aleksandra Medvedeva 14, Niš, Serbia,

dejan.krstic@gaf.ni.ac.rs

-313-

Na/Al molar ratios of raw materials and curing time on the mechanical properties of resulting

geopolymers [4]. K. Kaya et al. investigated structural and mechanical properties of RM – metakaolin

(MK) based geopolymers with varying RM contents 0 to 40 % RM in MK based geopolymer mixtures.

Authors investigated XRD, Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron

Microscopy (SEM) and Compressive Strength measurements to understand structure-performance

relationships in this system [5]. Z. Pan et al. investigated strength development and properties such as

resistance against carbonation, simulated seawater, diluted acid, sulfate solution and freeze and thaw

cycles of geopolymer mixtures made of 70 % of blast – furnace slag (BFS) and 30 % of RM [6].

This paper investigated potential use of RM as a binder for making geopolymer mortars. In the

examined geopolymer mortar made on the basis of FA a partial replacement of primary binder using RM

was performed, where the percentage of RM in the mass was 5 %, 10 %, 15 % and 20 %. Mechanical

characteristics of mortar were examined as well as the effects of freeze-thaw cycles on characteristics of

these mixes.

2. EXPERIMENTAL DETAILS

2.1. Materials

In this paper, the binders used were fly ash (FA) and red mud (RM). FA generated as a byproduct in

the thermal electric power plant Kostolac “B”, while RM is an aluminum processing generated byproduct

originating from the “Kombinat aluminijuma” Podgorica, Montenegro. Firstly, FA and RM are dried up

to the constant mass, and then they are sifted through the laboratory sieve having opening 0.09 mm. The

used binders are presented in Figure 1. The aggregate used for making mortar is the river aggregate from

the South Morava river, having maximum grain size of 2 mm. The admixture used to improve workability

of fresh mortar mix was superplasticizer (SP) SIKA 5380. In those mixes where addition of SP was

required, it was added up to a satisfactory flow, as well as extra water which was the same in all mixes.

Figure 1 – Used binder materials: a) FA, b) RM

Chemical composition of used FA and RM binders is given in Table 1 and it was obtained using the

chemical analysis and ASTM C618 standard. The used alkali activator is Sodium hydroxide – (SH) in the

granular form (Oltchim, Romania, p.a. 98,5%), and Sodium silicate – (SS) in the liquid form (Galenika-

Magmasil d.o.o. Serbia, with the SiO2:Na2O=1:2 contents ratio. The concentration of SH solution used in

this research was 10 molarity (M) and it was obtained by dissolving the granules in water.

Таble 1- Chemical composition (wt %) of the raw binder materials

Chemical

compounds SiO2 Fe2O3 Al2O3 CaO MgO SO3 P2O5 TiO2 Na2O K2O

FA 51,7 11,6 20,2 7,4 2,4 1,02 0,12 1,04 0,8 1,04

RM 32,8 4,63 9,92 2,37 0,22 - - - 0,12 0,12

a) b)

-314-

2.2. Preparation of geopolymer mortar

Four geopolymer mortar mixes and one standard cement mortar mix “E“ were tested for this paper.

Geopolymer mortar mixes were made with FA and RM whereby FA was replaced with RM in the amount

of 5 %, 10 %, 15 % and 20 % of the mass of the total quantity of binder. Those mixes are labeled as „5

RM“, „10 RM“, „15 RM“ and „20 RM“, respectively. Making of mortar mixes was performed in the

laboratory mortar mixer where the mass ratio of binders and sand was 1:3. 24 hours prior to the start of

mixing, SH had been dissolved, and it was mixed with SS 30 min prior to the start of mixing. After

mixing the alkali activators, binder material was added and the paste was mixed for 5 minutes. After that,

dry sand was added and the mixing continued for 5 minutes. The composition of mortar mixes is provided

in Table 2.

Таble 2- Mix design of geopolymer mortar mixtures

Mixture

no.

CEM III

(g)

FA

(g)

RM

(g)

SS/SH

(g)

W/B

(g)

B/S

(g)

SP

(%)

Extra

water

(g)

5 RM - 427,5 22,5 0,19 0,45 1:3 0,3 20

10 RM - 405 45 0,19 0,45 1:3 - 20

15 RM - 382,5 67,5 0,19 0,45 1:3 - 20

20 RM - 360 90 0,19 0,45 1:3 - 20

E 450 - - - 0,5 1:3 0,5 225

Fly ash (FA), Red mud (RM), Sodium silicate (SS), Sodium hydroxide (SH), Binder (B), Sand (S), Superplasticiser (SP)

After mixing, fresh mortar was placed in metal moulds having dimensions 4 x 4 x 16 cm. The moulds

were then wrapped in a plastic foil, and after 2 days the specimens were demoulded. Until the time of

testing, the specimens were kept at the laboratory temperature of around 22 ºC. The appearance of fresh

mortar mixtures is presented in Figure 2.

Figure 2 – Fresh geopolymer mortar mixtures: a) “5 RM”, b) “10 RM”, c) “15 RM” and d) “20 RM”

a) b)

c) d)

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2.3. Strength and freeze – thaw tests

Mechanical characteristics of geopolymer mortar mixes were tested in hardened state. The hardened

specimens in the form of prisms, 40 x 40 x 160 mm at the age of 3, 7, 28, 56 and 90 days were tested to

compressive and flexural strength according to the SRPS EN 196-1:2018 [7]. standard. A total of fifteen

prisms was made for each mortar mix. For each age, three mortar specimen prisms were tested.

The specimens belonging to batches having the same composition were tested by freeze – thaw cycle

tests. The tests were conducted on the mortar prisms having dimensions 4 x 4 x 16 cm whereby the

variation of compressive and flexural strength was observed. For each batch, three mortar prisms were

tested. The samples of geopolymer mixes were cured in ambient conditions to the age of 28 at the

temperature of 22 °C, while the cement mix was cured in water saturated condition. Upon reaching the

age of 28 days, the samples were subjected to the freeze – thaw test. One cycle consists of alternating

freezing and thawing in the water, whereby in each cycle, the samples spent 4 hours frozen at the

temperature of -20 °C, after which they spent 4 hours submerged in the standard temperature water. The

test was conducted according to the EN 14617-5:2005 standard [8] in 25 cycles. The specimens of mortar

mixtures after making are presented in Figure 3. After the conducted freeze-thaw test, the compressive

and flexural strength of the specimens was determined. Also was performed the calculation of KMf 25

and KMc 25 (coefficients of freeze/thaw resistance in flexural and compressive strength).

Where it KMf 25 is calculated according to formula:

Rf

RMfKMf (1)

Rc

RMcKMc (2)

Where:

RMf - is flexural strength average value of specimens after 25 freeze/thaw cycles,

Rf - is flexural strength average value of dried - unfrosted specimens,

RMc - is compressive strength average value of specimens after 25 freeze/thaw cycles,

Rc - is compressive strength average value of dried - unfrosted specimens.

Figure 3 – Specimens of hardened geopolymer mortar mixtures after demoilding

3. EXPERIMENTAL RESULTS AND DISCUSSION

Hardened mortar prisms were tested according to the procedure prescribed by the standard [7]. The

flexural strength value was obtained by measuring three specimens at each age, while the value of

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compressive strength was measured on six specimens. The results of flexural and compressive strength

of the tested specimens are presented in Figures 4 and 5.

Figure 4 and 5 – Flexural and compressive strength of geopolymer (“5 RM”, “10 RM”, “15 RM” and “20 RM”) and cement

(“E”) mortar mixtures

The results of testing of compressive and flexural strength of the specimens at the ages of 3, 7, 28, 56

and 90 days are shown in Figures 4 and 5. It can be concluded that the more mature the samples the

stronger the mortar. At the age of 3 days, the sample “10 RM” has the highest flexural and compressive

strength, and the form of the diagram on both diagram segments presented in Figure 4 and 5 is the same.

The measured flexural strength of the “10 RM” mix specimens, at the age of 7 and 28 days was 3,73

MPa and 6,87 MPa, respectively. At the age of specimens of 28 days, the highest value was measured for

the “5 RM” mix samples, which was 7,2 MPa, which is for around 4,5% more than the “10 RM“ mixture.

At the older ages of specimens, these two mixes have the approximately identical values. When testing

the flexural strength of the “15 RM” and “20 RM” mixes, at the age of samples of 28 days, the values 6,7

MPa and 6,6 MPa were measured (respectively) and until the end of testing, the increase of flexural

strength of around 5 % was measured.

According to the compressive strength testing results, presented in Figure 5, the highest value of

compressive strength at the tested age of specimens of 3 days is demonstrated by the reference mix “E”

prisms, which is about 2,1 more than the “10 RM“ mixture where the highest compressive strength was

measured. At the age of specimens of 28 days, the “10 RM” mix specimens had the highest value of

compressive strength and it was 47,82 MPa which is for around 25 % more than the reference mix „E“

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made with CEM III cement. The shape of the compressive strengths diagram at the age of specimens of

28 and 56 is the same, with a slight increase of strength up to 2 MPa, which was measured for the “15

RM“ mix. At the age of samples of 28, 56 and 90 days, the increase of compressive strength is evident,

but they, like the flexural strengths, are slight, with a maximum increase up to 12 %.

It can be concluded that all geopolymer mortar mixes meet the basic requirements in terms of

compressive and flexural strengths.

Figure 6 and 7 – Flexural and compressive strength of geopolymer („5 RM“, „10 RM“, „15 RM“ and „20 RM“) and cement

(„E“) mortar mixtures after 25 freeze-thaw cycles

The results of testing flexural and compressive strengths after 25 freeze/thaw cycles are presented in

Figures 6 and 7.

When measuring flexural strength, and calculating the flexural strength resistance coefficient, in all

the specimens of geopolymer mixes with the RM admixture, a decline of flexural strength was observed.

The value of this coefficient was determined for the following mixes: „5 RM“, „10 RM“, „15 RM“, „20

RM“ and „E“ and it is 63 %, 66 %, 75 %, 70 % and 98 %, respectively. The frost resistance parameter for

mixtures „15 RM“ and „E“ is higher than 75 % so it can be concluded, that those specimens are frost-

resistant for 25 cycles.

The compressive strength resistance coefficient was also calculated for the following mixes: „5 RM“,

„10 RM“, „15 RM“, „20 RM“ and „E“ and it is 92 %,83 %, 84 %, 89 % and 88 %, respectively. The

compressive strength resistance parameter is higher than 75 % for all tested specimens. It can be

concluded that the tested specimens of geopolymer mortar mad on the FA basis, with admixture of RM

are frost resistant for 25 cycles. Specimens after freeze – thaw test are presented in Figure 8.

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Figure 8 – Specimens of geopolymer mortar after 25 freeze-thaw cycles

4. CONCLUSIONS

According to the obtained characteristics, it can be concluded that the geopolymer mortars based on

FA originating from TEP „Kostolac B“ with the admixture of RM can be an adequate substitutions for

traditional cement mixes. Also, the following conclusions can be drawn:

At the age of samples of 28 days, all the tested samples had the compressive strength exceeding 44

MPa, i.e. exceeding 46,5 MPa at the age of 90 days.

All geopolymer mortar mixes meet the basic requirements regarding compressive and flexural

strengths.

Testing the frost resistance for 25 cycles leads to conclusion that the flexural strength resistance

parameter is higher than 75 % only in the „15 RM“ and „E“ mixes.

By calculating the compressive strength resistance parameter it was concluded that all the

specimens of geopolymer mortar made on the basis of fly ash with the red mud admixture are frost

resistant for 25 cycles.

Environmental and economic advantages of using geopolymer materials are reflected in use of

waste material, whose СО2 emission, when transforming it from a byproduct into a binder, is low.

It is necessary to conduct more detailed tests of physical and mechanical characteristics on mortars,

as well as on concretes.

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geopolymer mortar cured at different temperatures, Composites: Part B, 58, 2013, 371-377.

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ash geopolymer mortar, Journal of hazardous materials, 168, 2009, 44-50.

[3] He J., Zhang J., Yu Y., Zhang G.: Strength and microstructure of two geopolymers derived from

metakaolin and red mud-fly ash admixture: A comparative study, Construction and building

materials, 30, 2012, 80-91.

[4] Zhang M., El-Korchi T, Zhang G., Liang J., Tao M.: Synthesis factors affecting mechanical

properties, microstructure and chemical composition of red mud–fly ash based geopolymers,

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[5] Kaya K., Soyer – Uzun S.: Evolution of structural characteristics and compressive strength in

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[7] SRPS EN 196-1:2018, Methods of testing cement - Part 1: Determination of strength.

[8] SRPS EN 14617-5:2014, Agglomerated stone - Test methods - Part 5: Determination of freeze

and thaw resistance