comparisonoftheflexuralperformanceandbehaviourof fly-ash...

Research ArticleComparison of the Flexural Performance and Behaviour ofFly-Ash-Based Geopolymer Concrete Beams Reinforced withCFRP and GFRP Bars

Hemn Qader Ahmed Dilshad Kakasor Jaf and Sinan Abdulkhaleq Yaseen

Department of Civil Engineering Salahaddin University-Erbil Erbil Iraq

Correspondence should be addressed to Hemn Qader Ahmed hemnahmedsuedukrd

Received 4 April 2019 Revised 25 November 2019 Accepted 26 December 2019 Published 11 January 2020

Academic Editor Charles C Sorrell

Copyright copy 2020 Hemn Qader Ahmed et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

A construction system with high sustainability high durability and appropriate strength can be supplied by geopolymer concrete(GPC) reinforced with glass fibre-reinforced polymer (GFRP) bars and carbon fibre-reinforced polymer (CFRP) bars Few studiesdeal with a combination of GPC and FRP bars especially CFRP bars e present investigation presents the flexural capacity andbehaviour of fly-ash-based GPC beam reinforced with two different types of FRP bars six reinforced geopolymer concrete (RGPC)beams consisting of three specimens reinforced with GFRP bars and the rest with CFRP bars e beams were tested under four-point bending with a clear span of 2000mm e test parameters included the longitudinal-reinforcement ratio and the lon-gitudinal-reinforcement type including GFRP and CFRP Ultimate load first crack load load-deflection behaviour load-straincurve crack width and the modes of failure were studied e experimental results were compared with the equations rec-ommended by ACI 4401R-15 and CSA S806-12 for flexural strength and midspan deflection of the beams e results show thatthe reinforcement ratio had a significant effect on the ultimate load capacity and failure modee ultimate load capacity of CFRP-RGPC beams was higher than that of GFRP-RGPC more crack formations were observed in the CFRP-RGPC beams than in theGFRP-RGPC beams and the crack width in the GFRP-RGPC beams was more extensive than that in the CFRP-RGPC beamsBeams with lower reinforcement ratios experienced a fewer number of crack and a higher value of crack width while numerouscracks and less value of crack width were observed in beams with higher reinforcement ratio Beams with the lower reinforcementratios were more affected by the type of FRP bars and the deflection in GFRP-RGPC beams was higher than that in CFRP-RGPCbeams for the same corresponding load level ACI 4401R-15 and CSA S806-12 underestimated the flexural strength and midspandeflection of RGPC beams however CSA S806-12 predicted more accurately

1 Introduction

e ordinary portland cement concrete (OPCC) is one of themost commonly used and oldest building materials in theworld e order for this material is expected to increase inthe future due to the increasing demand for infrastructure inmany developing countriesmdashthe rising number of old anddeteriorating concrete structures that desperately need re-pair and rehabilitation e production of cement howevercontributes billions of tons of waste materials and about 7of the worldrsquos greenhouse gas yearly [1] e global envi-ronmental issues found during the manufacture of cement at

certain stages are undesirable Producing a ton of cementcause to launch the quantity of one ton of carbon dioxide tothe atmosphere this is due to the calcination of limestoneand burning of fossil gas during the manufacturing of ce-ment [2 3] e utilisation of green concrete in constructionis increasingly adopted by the construction industry owingto the drawbacks of normal concrete and the various in-herent benefits of green concrete Green concrete comes inmultiple forms such as high-volume fly ash concrete ul-trahigh performance concrete geopolymer concrete andlightweight concrete [4] In 1988 Davidovits introduced theterm ldquogeopolymerrdquo and discovered a new binder which may

HindawiAdvances in Materials Science and EngineeringVolume 2020 Article ID 3495276 15 pageshttpsdoiorg10115520203495276

be obtained by activating the (silicon and aluminium) in thesource material fly ash and rice husk ash with an alkalineactivator [5] Geopolymer concrete is a new type of concretewithout the use of cement and engineering scientists benefitfrom chemistry to produce GPC [6]

Recently it has been investigated environmental-friendly railway sleepers [7] modular retaining walls [8]sustainable buildings [9] and sustainable CFRP-reinforcedrecycled concrete for cleaner eco-friendly construction withnew and alternative materials [10] e researchers are nowproviding specific attention to the sustainable constructionthat motivates to investigate the concrete beams manufac-tured with GPC and FRP bars

e alkalinity of the concrete protects the steel rein-forcement from the corrosion Some structures have beenfound to counter the violent climate (marine system bridgesand garages) and exposure to deicing salts and combos ofmoisture temperature and chlorides decrease the alkalinityof the concrete then result in the corrosion of steel rein-forcement Because fibre-reinforced polymer (FRP) bars arenoncorrosive and nonmagnetic the issue of steel corrosionand the electromagnetic interface can be eliminated Ad-ditionally FRP bars have excessive tensile stress makingthem proper to use as a structural reinforcement [11]

Researchers have done several investigations on flexuralbehaviour of steel reinforced-reinforced geopolymer con-crete (SR-RGPC) beams Load-deflection characteristicsgained from steel reinforcedndashreinforced ordinary portlandconcrete (SR-ROPC) and SR-RGPC beams are almostsimilar e ultimate load-carrying capacity of SR-RGPCbeams was a little bit higher [12ndash16] e first cracking loadof SR-RGPC beams is better than that of SR-ROPC beamswhich shows better load-carrying capacity [17] Failure ofSR-RGPC beams is more ductile in a manner than SR-ROPCbeams accompanied by crushing of concrete in the com-pression zone and SR-RGPC beams exhibit a higher numberof narrow cracks compared to the SR-ROPC beams [18]Maranan et al have investigated the flexural strength of glassfibre-reinforced polymer-reinforced geopolymer concrete(GFRP-RGPC) beams e authors argued that the diameterof the bar had no significant effect on the beamrsquos flexuralperformance and the serviceability behaviour of a beamenhanced when the reinforcement ratio increases [19] eGFRP-RGPC beams have structural properties that aresuitable for civil infrastructure applications [20]

e adoption of FRP bars in place of steel bars as theprimary internal reinforcement for concrete structures isnow commonly practised to enhance the durability andprolong the serviceability of the structures while the use ofgeopolymer concrete instead of cement-based concrete isparticularly suitable for the fabrication of environment-friendly concrete structures With the advantageouscharacteristics of the FRP bars and the GPC includingtheir successful applications in the construction of variouscivil infrastructures combining FRP and GPC would offera promising technology in building new structures withhigh durability and high sustainability and with adequatestrength and structural integrity Most of the researchersfocused on replacing OPC by GPC in steel-reinforced

concrete structures ere is a limited study that combinedthe GPC with GFRP bars by taking limited parameters[19] and the only study that uses CFRP bars in GPC beamshas been undertaken by Ahmed et al [21] in which theinvestigated parameters were the reinforcement ratio andconcrete type A logical step therefore is to investigate theflexural behaviour of GPC beams reinforced with twocommon types of FRP bars (GFRP and CFRP) by achievinga precise comparison condition Reinforcement ratio andFRP types were taken as investigated parameterse crackpattern modes of failure load-deflection curves load-strain curves load-crack width and strain in concrete andbars are presented Furthermore the experimental resultscompared with the predicted flexural capacities using theproposed equations of ACI 4401R-15 [11] and CSA S806-12 [22]

2 Experimental Program

21 Test Specimens and Program e specimens weredesigned according to ACI 4401R-15 [11] e experi-mental program consists of six RGPC beams with the sametarget compressive strength (50MPa) and divided into twogroups three specimens reinforced with GFRP bars (G1)and the rest with CFRP bars (G2) [21] and the properties offabric texture coated FRP bars are presented in Table 1 Allthe test specimens have a height of 300mm while the widthof specimens in G1 and G2 [21] was 160 and 110mmrespectively e reason for choosing a different width inthe two groups is to achieve the same reinforcement ratio(ρf lt ρfb ρfblt ρf lt 14ρfb and ρf gt 14ρfb) and also tomaintain the three modes of failure (tension failure bal-anced failure and compression failure)e clear cover waskept at 20mm for all beams e length of the beams wasvaried (2200 or 2500mm) due to the requirement of de-velopment length by ACI 4401R-15 [11] Deformed steelbars of 6mm diameter were used for top longitudinalreinforcement and stirrups e stirrups were placed in acentre-to-centre spacing of 100mm to prevent the shearfailure of the beamse beams were simply supported overa clear span of 2000mm

e beam series were coded in the form (X1mdashGPC2) which stands for the following first letter (X)refers to FRP reinforcement type which may take the value(C or G) C for carbon and G for glass e second value(1) is the beam number in groups GPC refers to concretetype geopolymer concrete and finally the fourth value (2)is the concrete compressive strength e details of thespecimens are shown in Figure 1 and Table 2 shows the testprogram

22 Investigated Parameters e first parameter investigatedin this study was the reinforcement ratio (ρf ) with respect tothe balanced reinforcement ratio (ρfb) ree different rein-forcement ratio conditions (ρflt ρfb ρfblt ρflt 14ρfb andρfgt 14 ρfb) were taken for each group (G1 GFRP-RGPCbeams G2 CFRP-RGPC beams [21]) e second investi-gated parameter was the types of FRP bars Two common

2 Advances in Materials Science and Engineering

types of FRP bars were selected (GFRP and CFRP bars) aslongitudinal flexural reinforcement beams in groups G1 andG2 were reinforced with GFRP and CFRP bars [21]respectively

23 Materials Fabric texture coated GFRP and CFRP of6mmwere used as main flexural reinforcement while 6mmdeformed steel bars were used for the rest reinforcementSodium silicate solution (Na2Sio3) which is available in

liquid gel form with a chemical composition (Na2O-134SiO2-325 and water-541) and sodium hydroxide(NaOH) pellets with 98 purity which are available in flakesand pellet shapes were used for preparing the alkaline liquid

For preparing the GPC the constituent materials werethe low calcium fly-ash type F coarse aggregates with amaximum size of 952mm and fine aggregates e gradingof aggregates satisfied with the limits provided by ASTMC33[23] Sulphonated naphthalene formaldehyde super-plasticiser was used to enhance the workability

Table 1 Properties of FRP bars

Type Bar diameter (mm) Area Af (mm2) Ultimate tensile stress ffu (MPa) Elastic modulus Ef (GPa) Ultimate strain ()GFRP bars 6 28 1280 46 27CFRP bars 6 28 2000 148 14

P2 P2400 2 oslash 6mm (steel)

oslash 6mm 100mm cc (steel)

oslash 6mm (GFRP)2000X X

2 oslash 6mmGFRP

2 oslash 6mmCFRP

160 160 160

110110110

300

300

300

300

300

300

4 oslash 6mmGFRP

4 oslash 6mmCFRP

6 oslash 6mmGFRP

6 oslash 6mmCFRP

G01-GPC50

G01-GPC50

C01-GPC50

C01-GPC50

C02-GPC50

C02-GPC50

C03-GPC50

C03-GPC50G02-GPC50

G02-GPC50

G03-GPC50

G03-GPC50

100mm100mm100mm250mm250mm100mm

X

Figure 1 Dimensions and reinforcement details of the test specimens (dimensions are in mm)

Table 2 Test program

Group SpecimenID

FRPtype

Beam sectionCompressive strength fcprime

(MPa)Reinforcement ratio

conditionPredicted mode

failureb(mm)

h(mm)

G1G01-GPC50

GFRP 160 300 50ρflt ρfb Tension failure

G02-GPC50 ρfblt ρflt 14ρfb Balanced failureG03-GPC50 ρfgt 14ρfb Compression failure

G2C01-GPC50

CFRP 110 300 50ρflt ρfb Tension failure

C02-GPC50 ρfblt ρflt 14ρfb Balanced failureC03-GPC50 ρfgt 14ρfb Compression failure

Advances in Materials Science and Engineering 3

24 Control Specimens e control specimens of each beamwere tested at the same age of the tested beam ree cyl-inders were tested according to ASTM C39 [24] for concretecompressive strengths For splitting tensile strengths threecylinders were tested according to ASTM C 496 [25] reeprisms were tested for flexural strength of concreteaccording to ASTM C78 [26] Furthermore the modulus ofelasticity of GPC and Poissonrsquos ratio were determined bytesting three cylinders according to ASTM C469 [27] edensity for each mix was calculated based on cylinders andprisms Table 3 shows the results of the control specimens

25 Geopolymer Concrete Preparation e alkaline liquidwas prepared a day before casting First the sodium hy-droxide was dissolved in water according to the requiredmolarity (M) For M12 as an example the amount of so-dium hydroxide required to be dissolved in water to get onelitre of sodium hydroxide solution was (12x molecularweight of sodium hydroxide (4) 480 grams) and also theexperimentally determined weight of one litre of sodiumhydroxide of 12M was 1330 grams Second sodium silicateand sodium hydroxide solutions were mixed in a ratio of 25 1 which is the preferred ratio according to a previous re-search work [2]

Water-binder ratio was calculated as follows the amountof water in sodium silicate solution sodium hydroxide andextra water divided by the solid parts in sodium silicatesolution sodium hydroxide solution and fly ash

At casting day first the aggregates were placed into anelectric mixer and half of the extra water added and mixedfor 5min Fly ash was added and mixed for an additional5min after that the alkaline liquid was added to the mixturee remaining extra water and superplasticiser of 2 of theweight of fly ash were added e fresh GPC was cast intosteel moulds that were coated internally with special tape toavoid sticking of GPC with the mould e time betweencasting and placing the GPC specimens into an oven is calledldquorest periodrdquo e rest period was 60min before placing thecasted GPC into an oven and cured for 24 hr at a temper-ature of 70degC e oven-dry method was used for curing theGPC specimens

26 Mix Proportion In this study ten trial mixes wereperformed for achieving the required compressive strengthfor GPC beams e selected parameters for the trial mixeswere based on methods proposed by Ferdous et al [28] andPatankar et al [29] Molarity of sodium hydroxide alkaline-fly ash ratio and the water-binder ratio were taken asvariables Table 4 shows the details of trial mix proportionsEach trial consists of nine 100times 200mm cylinders whichwere tested according to ASTM C33 [23] after 3 7 and 28days

As a result increasing molarity of sodium hydroxidecaused to increase compressive strength up to 12M butwhen increased to 16M compressive strength decreasedWhen alkaline-fly ash ratio was increased it resulted in anincrease in the compressive strength and the optimum

water-binder ratio was 025 Figure 2 shows the effect oftrial mix parameters on compressive strength

27 Casting Beam Specimens From the trial mix results T3was selected as a proportion that has recorded the highestcompressive strength Before casting procedure the rein-forcement was prepared including the attaching straingauges e casting moulds for RGPC beams consist of steelmould while three cylinders 150times 300mm and three prisms75times 75times 400mm were used for casting the control speci-mens e mould cylinders and prisms were internallycoated with a special tape for the same reason mentionedearlier and then placed on an external vibrator

In this study the oven-dry method was used for curingthe GPC According to Hardjito et al [30] the suitablecuring temperature was in the range of 30degC to 90degC andthey found that curing of geopolymer concrete at highertemperatures up to 60degC yielded a higher compressivestrength than at a lower temperature Kirschner and Har-muth [31] obtained the highest strength using alkali-acti-vated metakaolin cured at 75degC during 4 hrs However theselection of curing temperature for the current study wasbased on the information mentioned e longer curingtime in the range of 4 to 96 hours produces higher com-pressive strength of fly ash-based geopolymer concreteaccording to Hardjito et al [30] However the increase instrength beyond 24 hours is not significant For this reason24 hours curing time was selected

After casting the specimens were left for 60min as a restperiod and then placed into the oven and cured for 24 hr at atemperature of 70degC Next day the specimens weredemoulded and placed in a laboratory environment until thetest day Figure 3 shows the casted beam specimen inside theoven

28 TestMethod and Instrumentations In this study a four-point static bending test method was employed as shown inFigure 4 e beams were loaded at midspan with twoconcentrated loads spaced at 400mm e load was appliedusing a hydraulic Jack of capacity 2500 kN at a rate of ap-proximately of 2 kNmin e midspan deflection wasmeasured using a dial gauge and cam recorder Furthermoredata logger was used for recording strains in electrical straingauges that were attached to the top surface of the beamsand the strains in FRP bars and also a crack measurementsensor were used for recording the crack width

3 Results and Discussion

e test results for the first cracking load ultimate loaddeflection and failure modes are presented in Table 5

31 Crack Pattern and Failure Mode e crack patterns atthe failure of GFRP-RGPC and CFRP-RGPC beams areshown in Figure 5 e crack patterns and modes of failurewere dissimilar due to the value of reinforcement ratio andthe type of used FRP bars All the tested beams were initially


uncracked before loading e initial cracking of the GFRP-RGPC and CFRP-RGPC beams occurred at the constantmoment region precisely under the load e first crackingload in GFRP-RGPC beams (avg 206 kN) was a bit higherthan that in CFRP-RGPC beams (avg 168 kN) even bothhave the same compressive strength and this due to the

beam width change for achieving the same reinforcementratio condition After the first cracking new cracks formedand the widths of the existing cracks continued to enlargewith the load in both GFRP-RGPC and CFRP-RGPC Atmaximum load more cracks formed in the CFRP-RGPCbeams (6 11 and 13) than in the GFRP-RGPC beams (5 6

Table 4 Trial mix proportion details and results

Trial G(kgm3)

S(kgm3)

FA(kgm3) M SS AF EW

(kgm3)SP

(kgm3)WBratio

Compressive strength fcprime

3 days(MPa)

7 days(MPa)

28 days(MPa)

T1 1230 660 400 12 25 045 0 3 02145 416 427 455T2 1230 660 400 12 25 045 32 2 03017 358 365 395T3 1230 660 400 12 25 045 14 2 02511 442 455 475T4 1230 660 400 12 25 045 48 2 03502 222 223 268T5 1230 660 400 16 25 045 36 2 03009 347 362 394T6 1230 660 400 8 25 045 27 2 03019 194 195 246T7 1230 660 400 8 25 045 43 2 03504 141 145 195T8 1230 660 400 8 25 04 50 2 03512 93 95 129T9 1230 660 400 8 25 035 57 2 03521 79 85 104T10 1230 660 400 12 25 045 38 2 03195 282 297 345Note G coarse aggregate S sand FA fly ash M molarity of sodium hydroxide SS sodium silicate-sodium hydroxide ratio AF alkaline-fly ash ratio EWextra water SP superplasticiser WB water-binder ratio

Table 3 Results of the control specimens

Group SpecimenID

Compressive strengthfcprime (Mpa)

Tensile strength fct(Mpa)

Flexural strength fr(Mpa)

Elastic modulus Ec(Mpa)

Poissonrsquosratio (μ)

Density(kgm3)

G1

G01-GPC50 4628 3599 481 29066 013 2427

G02-GPC50 4512 3167 492 26691 016 2387

G03-GPC50 4544 3272 446 25771 012 2370

G2

C01-GPC50 4466 3552 493 29582 016 2386

C02-GPC50 4749 4456 533 32272 014 2393

C03-GPC50 4541 4084 553 29582 015 2431

20

25

30

35

40

45

6 8 10 12 14 16

fprime c (M

Pa)

18NaOH molarity

(a)

20

25

30

35

40

45

50

02 025 03 035 04Water-binder

fprime c (M

Pa)

(b)

5

7

9

11

13

15

17

19

21

03 035 04 045 05Alkaline-fly ash ratio

fprime c (M

Pa)

(c)

Figure 2 Effect of trial mix parameters on compressive strength (a) Molarity effect (b) Water-binder effect (c) Alkaline-fly ash effect


and 8) and this is due to the types of FRP bars As averagethe crack width in the GFRP-RGPC beams (281 254 and261) was wider than that in the CFRP-RGPC beams (359164 and 123) and the reason beyond this is the highermodulus of elasticity of the CFRP bars than the GFRP bars

Beams G01-GPC50 and C01-GPC50 failed due to therupture of FRP bars (tension failure) exactly at midspan asshown in figures 5(a) and 5(b) and the beams were rein-forced with ρflt ρfb e beams experienced a fewer numberof cracks and a higher value of crack width compared withrest values of reinforcement ratio e cracks were mainly

vertical flexural cracks that were perpendicular to the lon-gitudinal axis of the beam

Failure modes in beams G02-GPC50 and C02-GPC50were a bit different as shown in figures 5(c) and 5(d)because of the critical reinforcement ratio conditionρfb lt ρf lt 14ρfb due to the assumed values for strain andtarget compressive strength Beam G02-GPC50 failed dueto the rapture of FRP bar and followed by the crushing ofconcrete under the load (balanced failure) failure whilebeam C02-GPC50 failed by crushing of concrete at com-pression zone between the two-point loads (compression

Figure 3 Casted beam specimen inside the oven

Figure 4 Test setup


failure) Beam G02-GPC50 recorder higher crack widthand lower number of crack over the beam C02-GPC50 As aresult for this particular reinforcement condition thelimitation provided by ACI 4401R-15 [11] gives differentmodes of failure for GFRP-RGPC and CFRP-RGPC beamseven satisfied with GFRP-RGPC beams

e vertical flexural cracks in the shear span becomemore inclined during the last stage of the loading inbeams G03-GPC50 and C03-GPC50 with reinforcementratio ρf gt 14ρfb due to the shear stresses Both beamsfailed due to the crushing of concrete at the top surface ofthe beams (compression failure) in different location asshown in Figures 5(e) and 5(f ) Crushing locations wereunder the point load and between point loads in G03-GPC50 and C03-GPC50 beams respectively due to thevariance in beam width which was the cause for theincrease in the distance between the neutral axis and topof the concrete e beams in this reinforcement con-dition recorded numerous cracks and less value of crackwidth besides other conditions while the crack widthseemed to be the smallest for beam C03-GPC50 e loadand crack width relationship for all the tested beams areshown in Figure 6

32 Load-Deflection Relationship e load-deflectioncurves at midspan of the tested beams are shown in Figures 7and 8 In general two major stages were observed First alinear branch with a steep slope was noticed which related tothe uncracked condition of the beams where only the GPCsustained all the applied loads Secondly when the crackingload achieved a drop in the slop was observed due to theprogressive cracks of the beams and the almost linear seg-ment was observed until failure except sudden drop down inloads in every earlier crack formations especially for rein-forcement ratios ρflt ρfb

e test results show that the ultimate load of both theGFRP-RGPC and CFRP-RGPCC beams increased with thereinforcement ratio For the GFRP-RGPC beams the ulti-mate loads of the G02-GPC50 and G03-GPC50 beams in-creased respectively by 733 and 1526 compared withthat of the G01-GPC50 beam as shown in Figure 7(a) Forthe CFRP-RGPC beams the ultimate loads of the C02-GPC50 and C03-GPC50 beams increased respectively by369 and 509 compared with that of the C01-GPC50beam as shown in Figure 7(b)

e test results also show that the deflection of theGFRP-RGPC and CFRP-RGPCC beams for the same load

Table 5 Results of the tested beams

Group SpecimenID Reinforcement ratio ρf First crack load Pcr (kN) Ultimate load Pu (kN) Deflection Δ (mm) Failure mode

G1

G01-GPC50 067ρfb 1830 57700 2842 Tension failureG02-GPC50 134ρfb 208 100000 2898 Balanced failure

G03-GPC50 207ρfb 2260 145800 3517 Compressionfailure

G2

C01-GPC50 066ρfb 148 1125 275 Tension failure

C02-GPC50 138ρfb 157 1541 225 Compressionfailure


(a) (b)

(c) (d)

(e) (f )

Figure 5 Crack pattern and failure mode (a) G01-GPC50 (b) C01-GPC50 (c) G02-GPC50 (d) C02-GPC50 (e) G03-GPC50 (f ) C03-GPC50


level decreased with the increase in the reinforcement ratioFor the GFRP-RGPC beams the deflection of the G01-GPC50 beam was higher than that of the G02-GPC50 andG03-GPC50 beams as shown in Figure 7(a) For the CFRP-RGPC beams the deflection of the C01-GPC50 beam washigher than that of the C02-GPC50 and C03-GPC50 beamsas shown in Figure 7(b)

e load-deflection curves of the test beams with dif-ferent types of FRP bar are shown in Figure 8 For the samereinforcement ratio condition the ultimate load capacity ofCFRP-RGPC beams was higher than that of GFRP-RGPCand this is due to the excessive tensile strength provided byCFRP bars e ultimate load of C01-GPC50 C02-GPC50and C02-GPC50 beams was higher than that of G01-GPC50

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)

G01-GPC50G02-GPC50G03-GPC50

(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)

C01-GPC50C02-GPC50C03-GPC50

(b)

Figure 7 Load-deflection curves-reinforcement ratio effect (a) G1-GFRP-RGPC (b) G2-CFRP-RGPC

020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50

Figure 6 Load and crack width relationship


G02-GPC50 and G02-GPC50 beams by 953 541 and165 respectively ese results indicate that the beamswith the lower reinforcement ratios were more affected bythe type of FRP bars because the tension failure dramaticallydepends on the tensile strength of the FRP bar Moreoverthe results also show that the deflection in GFRP-RGPCbeams was higher than that in GFRP-RGPC beams for thesame corresponding load level and this is due to the higherultimate strain in GFRP bars

e effect of reinforcement ratio on the ultimate load anddeflection at a load level of 50 kN are shown inFigure 9 Lower reinforcement ratio (ρfρfb 115) for CFRP-

RGPC beams is required to achieve the same load-carryingcapacity for example (140 kN) rather than (ρfρfb 205) forGFRP-RGPC beams as shown in Figure 9(a) For the samereinforcement ratio the deflection inGFRP-RGPC beamswashigher than that in CFRP-RGPC beams while the differencewas more obvious for lower reinforcement ratio rather thanhigher reinforcement ratio as shown in Figure 9(b)

33 Strain in Longitudinal Reinforcement and GeopolymerConcrete Load-strain curves for the tested beam specimensare shown in Figure 10 e strain in FRP bars and GPC at

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)

Figure 8 Load-deflection curves-FRP type effect (a) ρflt ρfb (b) ρfblt ρflt 14ρfb (c) ρfgt 14ρfb


0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ

GFRP-RGPC beamsCFRP-RGPC beams

(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)

Figure 9 Reinforcement ratio effect on (a) ultimate load and (b) deflection

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued


the top surface was measured at the midspan of the spec-imens and the positive and negative strain values oncurves represent the strains in FRP and GPC respectivelyAt first the tested beam specimens shared almost the samesmall increase of linear strain segment in both FPR barsand PGC with the applied load until the initial crack loadSecondly a rapid strain increase and the almost stableload were observed after the initial crack formation Fi-nally the almost linear segment of load-strain curves wasnoticed until failure in FRP bars and a parabolic segmentin GPC Overall the effect of the process of crack for-mation on strain-curves in both FRP and GPC can benoticed

Strain in FRP and GPC and failure modes are in greatrelation For G01-GPC50 and C01-GPC50 beams the strainin FRP bars almost reached the ultimate strain while thestrains in GPC did not reach the ultimate strain whichindicates a tension failure mode For G02-GPC50 beam thestrain in FRP bar and GPC is near the ultimate strain whichindicates balanced failure For C02-GPC50 G03-GPC50and C03-GPC50 beams the strain in concrete almostreached the ultimate strain but not in FRP bars whichindicates the compression failure mode

4 Theoretical Prediction

In this study the theoretical flexural capacities (Mu) andultimate deflection (Δu) of GFRP-RGPC and CFRP-RGPCbeams were computed based on the equations provided byACI 4401R-15 [11] and CSA S806-12 [22] and comparedwith experimental flexural capacities (Muminus exp) and de-flection (Δuminus exp) results

41 Equations Provided by ACI 441R-15 and CSA S806-12According to ACI 4401R-15 [11] the moment of resistanceof a concrete beam reinforced with FRP bars can be de-termined based on strain compatibility internal forceequilibrium and the controlling mode of failure (tensionfailure or compression failure) e predicted failure modecan be determined by comparing the reinforcement ratio ρf(equation (1)) to the balanced reinforcement ratio ρfb(equation (2)) which is the rate for indicating concretecrushing and FRP rapture as follows

ρf Af

bd (1)

where Af is the area of FRP bar b is the width of therectangular cross section and d is the distance from extremecompression fibre to the centroid of FRP bars

ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)

where fcprime is the specified compressive strength of concrete ffuis the ultimate tensile stress of FRP bars Ef is the elasticmodulus of FRP εcu is the ultimate strain in concrete takenequal to 0003 and the factor β1 can be calculated as follows

β1 085 minus005 fcprime minus 28( 1113857

7ge 065 (3)

First if ρfgt ρfb the beam is considered as overreinforcedthe controlling limit state is crushing of concrete and themoment of resistance (M) can be calculated as follows

M ρfff bd2 1 minus 059

ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)

Figure 10 Load-strain curves (a) G1-GFRP-RGPC (b) G2-CFRP-RGPC


where ff is the tensile strength of the FRP bars and can becalculated using the following equation

ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972

minus 05Efεcu le ffu (5)

Secondly if ρfblt ρflt 14ρfb this particular condition candescribed by a transition zone when crashing of concretefollowed by the rapture of FRP bar (balanced) failure Fi-nally if ρflt ρfb the beam is considered as underreinforcedthe controlling limit is FRP rapture andM can be estimatedusing the following equation

M Af ffu d minusβ1c2

1113888 1113889

β1c Afff

085fcprimeb

(6)

where c is the distance from the extreme compression fibreto the neutral axis

For deflection calculation ACI 4401R-15 [11] dependson the effective moment of inertia (Ie) in cracked RFPreinforced concrete beams which can be calculated asfollows

Ie Icr

1 minus c McrMa( 11138572 1 minus IcrIg1113872 11138731113960 1113961

(7)

where Icr is the cracked moment of inertia Ig is the grossmoment of inertia Mcr is the cracking moment and Ma isthe maximum service moment and factor c which dependson loading and boundary conditions for a simply supportedbeam with four-point loading can be calculated as follows

c 3(aL) minus 16 McrMa( 1113857(aL)3 + 12(aL)3

3(aL) minus 4(aL)3 (8)

Once Ie is calculated midspan deflection Δ can be cal-culated using solid mechanics formula here for four-pointbending equation (9) can be used

Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)

where P is the service load which is taken equal to 040 timesthe ultimate experimental loads as suggested by Wang andBelarbi [32] L is the span length a is the shear-span lengthand Ec is the elastic modulus of concrete

According to CSA S806-12 [22] FRP-reinforced con-crete beams were preferred to be designed in such a way thatthe controlling limit state is crushing of concrete and єcu istaken equal to 00035 and it also depends on strain com-patibility and internal force equilibrium Balanced rein-forcement ratio ρfb can be calculated from equation (10)while factors α1 and β1 can be calculated from equations (11)and (12) respectively

ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)

α1 085 minus 00015fcprime ge 067 (11)

β1 097 minus 00025fcprime ge 067 (12)

e moment of resistance (M) can be calculated fromequation (13) and the stress in the FRP bar ff can be cal-culated by using equation (14) where the neutral axis c canbe determined by using equation (15)

M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)

ff AfEfεcu(d minus c)

clt ffu (14)

α1β1fcprimebc minus AfEfεcu(d minus c)

c 0 (15)

eCSA S806-12 [22] states that the deflection Δ shall becomputed by methods based on the integration of thecurvature at sections along the spanis can be an intensivecalculation process subject to human error so the code alsoprovides closed-form equations for the common loading andboundary conditions For four-point loading the deflectionΔ can be calculated as follows

Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)

where Lg is the uncracked length in half of the beam andfactor η can be calculated as follows

η 1 minusIcr

Ig (17)

42 Comparing Experimental Results with lteoreticalPredictions e predicted moment of resistance (M) anddeflection (Δ) at service load calculated by ACI 4401R-15[11] CSA S806-12 [22] and experimental are compared asshown in Table 6 e prediction equations provided by ACI4401R-15 [11] and CSA S806-12 [22] underestimated theflexural capacity of RGPC beams by 703 and 781 re-spectively ACI 4401R-15 [11] predicted more accurately forGFRP-RGPC beams (737) than that for CFRP-RGPCbeams (663) while CSA S806-12 [22] predicted a bit better(826) for GFRP-RGPC beams than (737) for CFRP-RGPC beams

On the other hand the prediction equations provided byACI 4401R-15 [11] and CSA S806-12 [22] also over-estimated the midspan deflection at service load of GFRP-RGPC beams while the values are in the closest form forCFRP-RGPC beams Figure 11 shows a graphical compar-ison for the moment of resistance provided by ACI 4401R-15 [11] CSA S806-12 [22] and experimental results


43 Comparison between GFRP-RGPC CFRP-RGPC andGFRP-ROPC Beams e comparison between the normal-ised flexural capacity of GFRP-RGPC CFRP-RGPC andGFRP-ROPCbeams is shown in Table 7eGFRP-RGPC andCFRP-RGPC beams that were considered in the study havenearly similar concrete strengths and amount and type ofreinforcements In general the bending-moment capacities ofthe tested beams GFRP-RGPC beams were higher than the

GFRP-ROPC beams is is due to the enhanced mechanicalproperties of the geopolymer concrete compared with normalconcrete and the provision of lateral ties within the constantbending-moment zone that provided confinement accordingto the previous studies e higher concrete compressivestrength is used in this study compared with the previous onesOn the other hand the difference in normalised flexural ca-pacity was noticed between CFRG-RGPC (4244) and GFRP-

Table 6 eoretical prediction and experimental resultndashA Comparison

Group Specimen IDMoment resistance Deflections at service load Comparisons

Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)

ΔCSA(mm) MACIMexp() MCSAMexp()

G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80

G01-GPC20 G02-GPC20 G03-GPC20 G04-GPC35 G05-GPC35 G06-GPC35

Mom

ent o

f res

istan

ce (k

Nmiddotm

)

ACI 4401R-15CSA S806-12Experimental

Figure 11 Moment of resistance-graphical comparison

Table 7 Normalised flexural capacity of GFRP-RGPC CFRP-RGPC and GFRP-ROPC beams

Reference Beam ρf Concrete type FRP type Normalised flexural capacity (Mufcprime middot bd2)

Current study G02-GPC50 139ρfb GPC GFRP 4244C02-GPC50 140ρfb GPC CFRP 12471

Maranan et al [20]GFRP-RGC-4-127 113 GPC GFRP 477GFRP-RGC-3-159 118 GPC GFRP 543GFRP-RGC-2-190 100 GPC GFRP 496

Toutanji and Saafi [33] GB3-1 110 OPC GFRP 446GB3-2 110 OPC GFRP 473

Benmokrane and Masmoudi [34] ISO1 110 OPC GFRP 351ISO2 110 OPC GFRP 367

Benmokrane et al [35] ISO30-2 101 OPC GFRP 359


RGPC (12471) due to the higher tensile stress of CFRP barsand difference in beamsrsquo cross section

5 Conclusions

e flexural capacity and behaviour of RGPC beams withGFRP and CFRP bars were investigated under four-pointbending test Based on the experimental results the fol-lowing conclusions were made

(i) More crack formations were observed in theCFRP-RGPC beams than in the GFRP-RGPCbeams and the crack width in the GFRP-RGPCbeams was wider than that in the CFRP-RGPCbeams

(ii) Beams with lower reinforcement ratios experi-enced a fewer number of cracks and a higher valueof crack width while the beams with higher re-inforcement ratio experienced numerous cracksand less value of crack width

(iii) e increase in reinforcement ratio had a signif-icant effect on first cracking load and ultimate loadthe ultimate load of GFRP-RGPC and CFRP-RGPC beam increased by 1526 and 509 re-spectively for the same increase in reinforcementratio

(iv) e ultimate load capacity of CFRP-RGPC beamswas higher than that of GFRP-RGPC for differentreinforcement conditions of ρflt ρfb ρfblt ρflt 14ρfband ρfgt 14ρfb by 953 541 and 165 re-spectively and this is due to the excessive tensilestrength provided by CFRP bars

(v) Beams with the lower reinforcement ratios weremore affected by the type of FRP bars because thetension failure dramatically depends on the tensilestrength of the FRP bar e deflection in GFRP-RGPC beams was higher than that in CFRP-RGPCbeams for the same corresponding load level andthis is due to the lower modulus of elasticity ofGFRP than CFRP bars

(vi) Based on the findings of this study CFRP bars areconsidered better than GFRP bars in GPC beamsbecause for the same reinforcement ratio the ul-timate load for CFRP-RGPC beams was higherthan that for GFRP-RGPC beams Same rein-forcement ratio achieved with less cross section ofCFRP-RGPC beams means minimising the deadload CFRP-RGPC beams recorded the lower valueof crack width

(vii) ACI 4401R-15 and CSA S806-12 underestimatedthe moment of resistance of RGPC beams by 703and 781 respectively ACI 4401R-15 predictedmore accurately for GFRP-RGPC beams (737)than that for CFRP-RGPC beams (663) whileCSA S806-12 predicted a bit better (826) forGFRP-RGPC beams than (737) for CFRP-RGPCbeams

(viii) ACI 4401R-15 and CSA S806-12 overestimatedthe midspan deflection at service load of GFRP-RGPC beams while the values are in the closestform for CFRP-RGPC beams

e implications of this research for constructionpractice and research are as follows

(i) Applications of GPC reinforced with FRP bars canbe an ideal choice in civil infrastructural applica-tions since conventional cement production ishighly energy-intensive and causes global envi-ronmental issues Because FR bars are noncorrosiveand nonmagnetic the problem of steel corrosionand the electromagnetic interface can be elimi-nated Additionally FRP bars have excessive ten-sile-stress making them proper to use as astructural reinforcement

(ii) Based on the findings of this study the followingsuggestions and recommendations may be consid-ered for future studies studying the flexural be-haviour of geopolymer concrete beams with differenttypes of FRP bars (GFRP and AFRP) shear strengthand behaviour of GPC beams reinforced with FRPbars and because of the difference in property ofGPC and OPC more comparison could be estab-lished in future studies

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] P K Mehta ldquoReducing the environmental impact of con-creterdquo Concrete International vol 23 no 10 pp 61ndash66 2001

[2] D Hardjito and B V Rangan Development and Properties ofLow-Calcium Fly Ash-Based Geopolymer Concrete Faculty ofEngineering Curtin University of Technology GCI PerthAustralia 2005

[3] R McCaffrey ldquoClimate change and the cement industryrdquo inGlobal Cement and Lime Magazine (Environmental SpecialIssue) pp 15ndash19 2002

[4] K M Liew A O Sojobi and L W Zhang ldquoGreen concreteprospects and challengesrdquo Construction and Building Mate-rials vol 156 pp 1063ndash1095 2017

[5] D Hardjito and S E Wallah ldquoIntroducing fly ash-basedgeopolymer concrete manufacture and engineering proper-tiesrdquo in Proceedings of the 30th Conference on Our World inConcrete amp Structures Singapore August 2005

[6] N A Lloyd and B V Rangan ldquoGeopolymer concrete with flyashrdquo in Proceedings of the Second International Conference onsustainable construction Materials and Technologies AnconaItaly June 2010

[7] W Ferdous A Manalo G Van Erp T Aravinthan andK Ghabraie ldquoEvaluation of an innovative composite railway


sleeper for a narrow-gauge track under static loadrdquo Journal ofComposites for Construction vol 22 no 2 Article ID04017050 2018

[8] W Ferdous Y Bai A D Almutairi S Satasivam and J JeskeldquoModular assembly of water-retaining walls using GFRPhollow profiles components and connection performancerdquoComposite Structures vol 194 pp 1ndash11 2018

[9] W Ferdous Y Bai T D Ngo A Manalo and P MendisldquoNew advancements challenges and opportunities of multi-storey modular buildingsmdasha state-of-the-art reviewrdquo Engi-neering Structures vol 183 pp 883ndash893 2019

[10] L W Zhang A O Sojobi and K M Liew ldquoSustainableCFRP-reinforced recycled concrete for cleaner eco-friendlyconstructionrdquo Journal of Cleaner Production vol 233pp 56ndash75 2019

[11] ACI 4401R-15 Guide for the Design and Construction ofConcrete Reinforced with Fiber Reinforced Polymers (FRP)Bars American Concrete Institute Farmington Hills MIUSA 2015

[12] S Kumaravel and S irugnanasambandam ldquoFlexural be-haviour of reinforced low calcium fly ash based geopolymerconcrete beamrdquo Global Journal of Research in Engineeringvol 13 no 8 2013

[13] S Kumaravel and S irugnanasambandam ldquoFlexural be-haviour of geopolymer concrete beamsrdquo International Journalof Advanced Engineering Research and Studies vol 4 p 62013

[14] C K Madheswaran P S Ambily N P Rajamane andG Arun ldquoStudies on flexural behaviour of reinforced geo-polymer concrete beams with lightweight aggregatesrdquo In-ternational Journal of Civil and Structural Engineering vol 4no 3 p 295 2014

[15] A Hutagi and R Khadiranaikar ldquoFlexural behavior ofreinforced geopolymer concrete beamsrdquo in Proceedings of the2016 International Conference on Electrical Electronics andOptimization Techniques (ICEEOT) pp 3463ndash3467 ChennaiIndia March 2016

[16] B S C Kumar and K Ramesh ldquoFlexural behavior of rein-forced geopolymer concrete beams with GGBS and meta-kaolinrdquo Global Journal of Engineering Science and Researchesvol 4 2017

[17] M K angamanibindhu and D S R Murthy ldquoFlexuralbehavior of reinforced geopolymer concrete beams partiallyreplaced with recycled coarse aggregatesrdquo InternationalJournal of Civil Engineering and Technology (IJCIET) vol 6no 7 pp 13ndash23 2015

[18] R Abraham S Raj and V Abraham ldquoStrength and behaviourof geopolymer concrete beamsrdquo International Journal ofInnovative Research in Science Engineering and Technologyvol 2 no 1 pp 159ndash166 2013

[19] G B Maranan A C Manalo B BenmokraneW Karunasena and P Mendis ldquoEvaluation of the flexuralstrength and serviceability of geopolymer concrete beamsreinforced with glass-fibre-reinforced polymer (GFRP) barsrdquoEngineering Structures vol 101 pp 529ndash541 2015

[20] G B Maranan A C Manalo W KarunasenaB Benmokrane and P Mendis ldquoFlexural response of GFRP-reinforced geopolymer concrete beamsrdquo in Proceedings of the27th Biennial National Conference of the Concrete Institute ofAustralia (Concrete 2015) pp 287ndash296 Melbourne AustraliaAugust 2015

[21] H Q Ahmed D K Jaf and S A Yaseen ldquoFlexural strengthand failure of geopolymer concrete beams reinforced with

carbon fibre-reinforced polymer barsrdquo Construction andBuilding Materials vol 231 p 117185 2020

[22] CSA S806-12 Design and Construction of Building Structureswith Fiber-Reinforced Polymers Canadian Standard Associ-ation (CSA) Ontario Canada 2012

[23] ASTM C33 Standard Specification for Concrete AggregatesASTM International West Conshohocken PA USA 1999

[24] ASTM C39C39M Standard Test Method for CompressiveStrength of Cylindrical Concrete Specimens ASTM Interna-tional West Conshohocken PA USA 1999

[25] ASTM C496C496M Standard Test Method for SplittingTensile Strength of Cylindrical Concrete Specimens ASTMInternational West Conshohocken PA USA 2004

[26] ASTMC78C78M Standard Test Method for Flexural Strengthof Concrete (Using Simple Beam with ltird-Point Loading)ASTM International West Conshohocken PA USA 2013

[27] ASTM C469C469M Standard Test Method for Static Mod-ulus of Elasticity and Poissonrsquos Ratio of Concrete in Com-pression ASTM International West Conshohocken PAUSA 2014

[28] M Ferdous O Kayali and A Khennane ldquoA detailed pro-cedure of mix design for fly ash based geopolymer concreterdquoin Proceedings of the 2013 Asia-Pacific Conference on FRP inStructures (APFIS 2013) pp 11ndash13 Melbourne AustraliaDecember 2013

[29] S V Patankar Y M Ghugal and S S Jamkar ldquoMix design offly ash based geopolymer concreterdquo in Advances in StructuralEngineering pp 1619ndash1634 Springer New Delhi India 2015

[30] D Hardjito S E Wallah D M J Sumajouw et al ldquoFactorsinfluencing the compressive strength of fly ash-based geo-polymer concreterdquo Civil Engineering Dimension vol 6 no 2pp 88ndash93 2004

[31] A Kirschner and H Harmuth ldquoInvestigation of geopolymerbinders with respect to their application for building mate-rialsrdquo Ceramics Silikaty vol 48 pp 117ndash120 2004

[32] H Wang and A Belarbi ldquoFlexural behavior of fiber-rein-forced-concrete beams reinforced with FRP rebarsrdquo in Pro-ceedings of the SP-230 7th International Symposium on Fiber-Reinforced (FRP) Polymer Reinforcement for Concrete Struc-tures vol 51 no 230 pp 895ndash914 Kansas City MO USANovember 2005

[33] H A Toutanji and M Saafi ldquoFlexural behavior of concretebeams reinforced with glass fiber-reinforced polymer (GFRP)barsrdquoACI Structural Journal vol 97 no 5 pp 712ndash719 2000

[34] B Benmokrane and R Masmoudi ldquoFlexural response ofconcrete beams reinforced with FRP reinforcing barsrdquo ACIStructural Journal vol 93 no 1 pp 46ndash55 1996

[35] B Benmokrane O Chaallal and R Masmoudi ldquoGlass fibrereinforced plastic (GFRP) rebars for concrete structuresrdquoConstruction and Building Materials vol 9 no 6 pp 353ndash364 1995


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Journal of


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nom

ate

ria

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Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

be obtained by activating the (silicon and aluminium) in thesource material fly ash and rice husk ash with an alkalineactivator [5] Geopolymer concrete is a new type of concretewithout the use of cement and engineering scientists benefitfrom chemistry to produce GPC [6]

Recently it has been investigated environmental-friendly railway sleepers [7] modular retaining walls [8]sustainable buildings [9] and sustainable CFRP-reinforcedrecycled concrete for cleaner eco-friendly construction withnew and alternative materials [10] e researchers are nowproviding specific attention to the sustainable constructionthat motivates to investigate the concrete beams manufac-tured with GPC and FRP bars

e alkalinity of the concrete protects the steel rein-forcement from the corrosion Some structures have beenfound to counter the violent climate (marine system bridgesand garages) and exposure to deicing salts and combos ofmoisture temperature and chlorides decrease the alkalinityof the concrete then result in the corrosion of steel rein-forcement Because fibre-reinforced polymer (FRP) bars arenoncorrosive and nonmagnetic the issue of steel corrosionand the electromagnetic interface can be eliminated Ad-ditionally FRP bars have excessive tensile stress makingthem proper to use as a structural reinforcement [11]

Researchers have done several investigations on flexuralbehaviour of steel reinforced-reinforced geopolymer con-crete (SR-RGPC) beams Load-deflection characteristicsgained from steel reinforcedndashreinforced ordinary portlandconcrete (SR-ROPC) and SR-RGPC beams are almostsimilar e ultimate load-carrying capacity of SR-RGPCbeams was a little bit higher [12ndash16] e first cracking loadof SR-RGPC beams is better than that of SR-ROPC beamswhich shows better load-carrying capacity [17] Failure ofSR-RGPC beams is more ductile in a manner than SR-ROPCbeams accompanied by crushing of concrete in the com-pression zone and SR-RGPC beams exhibit a higher numberof narrow cracks compared to the SR-ROPC beams [18]Maranan et al have investigated the flexural strength of glassfibre-reinforced polymer-reinforced geopolymer concrete(GFRP-RGPC) beams e authors argued that the diameterof the bar had no significant effect on the beamrsquos flexuralperformance and the serviceability behaviour of a beamenhanced when the reinforcement ratio increases [19] eGFRP-RGPC beams have structural properties that aresuitable for civil infrastructure applications [20]

e adoption of FRP bars in place of steel bars as theprimary internal reinforcement for concrete structures isnow commonly practised to enhance the durability andprolong the serviceability of the structures while the use ofgeopolymer concrete instead of cement-based concrete isparticularly suitable for the fabrication of environment-friendly concrete structures With the advantageouscharacteristics of the FRP bars and the GPC includingtheir successful applications in the construction of variouscivil infrastructures combining FRP and GPC would offera promising technology in building new structures withhigh durability and high sustainability and with adequatestrength and structural integrity Most of the researchersfocused on replacing OPC by GPC in steel-reinforced

concrete structures ere is a limited study that combinedthe GPC with GFRP bars by taking limited parameters[19] and the only study that uses CFRP bars in GPC beamshas been undertaken by Ahmed et al [21] in which theinvestigated parameters were the reinforcement ratio andconcrete type A logical step therefore is to investigate theflexural behaviour of GPC beams reinforced with twocommon types of FRP bars (GFRP and CFRP) by achievinga precise comparison condition Reinforcement ratio andFRP types were taken as investigated parameterse crackpattern modes of failure load-deflection curves load-strain curves load-crack width and strain in concrete andbars are presented Furthermore the experimental resultscompared with the predicted flexural capacities using theproposed equations of ACI 4401R-15 [11] and CSA S806-12 [22]

2 Experimental Program

21 Test Specimens and Program e specimens weredesigned according to ACI 4401R-15 [11] e experi-mental program consists of six RGPC beams with the sametarget compressive strength (50MPa) and divided into twogroups three specimens reinforced with GFRP bars (G1)and the rest with CFRP bars (G2) [21] and the properties offabric texture coated FRP bars are presented in Table 1 Allthe test specimens have a height of 300mm while the widthof specimens in G1 and G2 [21] was 160 and 110mmrespectively e reason for choosing a different width inthe two groups is to achieve the same reinforcement ratio(ρf lt ρfb ρfblt ρf lt 14ρfb and ρf gt 14ρfb) and also tomaintain the three modes of failure (tension failure bal-anced failure and compression failure)e clear cover waskept at 20mm for all beams e length of the beams wasvaried (2200 or 2500mm) due to the requirement of de-velopment length by ACI 4401R-15 [11] Deformed steelbars of 6mm diameter were used for top longitudinalreinforcement and stirrups e stirrups were placed in acentre-to-centre spacing of 100mm to prevent the shearfailure of the beamse beams were simply supported overa clear span of 2000mm

e beam series were coded in the form (X1mdashGPC2) which stands for the following first letter (X)refers to FRP reinforcement type which may take the value(C or G) C for carbon and G for glass e second value(1) is the beam number in groups GPC refers to concretetype geopolymer concrete and finally the fourth value (2)is the concrete compressive strength e details of thespecimens are shown in Figure 1 and Table 2 shows the testprogram

22 Investigated Parameters e first parameter investigatedin this study was the reinforcement ratio (ρf ) with respect tothe balanced reinforcement ratio (ρfb) ree different rein-forcement ratio conditions (ρflt ρfb ρfblt ρflt 14ρfb andρfgt 14 ρfb) were taken for each group (G1 GFRP-RGPCbeams G2 CFRP-RGPC beams [21]) e second investi-gated parameter was the types of FRP bars Two common











2 oslash 6mmGFRP

2 oslash 6mmCFRP

160 160 160

110110110

300

300

300

300

300

300

4 oslash 6mmGFRP

4 oslash 6mmCFRP

6 oslash 6mmGFRP

6 oslash 6mmCFRP

G01-GPC50

G01-GPC50

C01-GPC50

C01-GPC50

C02-GPC50

C02-GPC50

C03-GPC50

C03-GPC50G02-GPC50

G02-GPC50

G03-GPC50

G03-GPC50


X



Group SpecimenID

FRPtype




failureb(mm)

h(mm)

G1G01-GPC50



G2C01-GPC50






















Trial G(kgm3)

S(kgm3)

FA(kgm3) M SS AF EW

(kgm3)SP

(kgm3)WBratio


3 days(MPa)

7 days(MPa)

28 days(MPa)



Group SpecimenID






Density(kgm3)

G1

G01-GPC50 4628 3599 481 29066 013 2427

G02-GPC50 4512 3167 492 26691 016 2387

G03-GPC50 4544 3272 446 25771 012 2370

G2

C01-GPC50 4466 3552 493 29582 016 2386

C02-GPC50 4749 4456 533 32272 014 2393

C03-GPC50 4541 4084 553 29582 015 2431

20

25

30

35

40

45

6 8 10 12 14 16

fprime c (M

Pa)

18NaOH molarity

(a)

20

25

30

35

40

45

50

02 025 03 035 04Water-binder

fprime c (M

Pa)

(b)

5

7

9

11

13

15

17

19

21


fprime c (M

Pa)

(c)








Figure 4 Test setup









G1



G2




(a) (b)

(c) (d)

(e) (f )





0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls













2 oslash 6mmGFRP

2 oslash 6mmCFRP

160 160 160

110110110

300

300

300

300

300

300

4 oslash 6mmGFRP

4 oslash 6mmCFRP

6 oslash 6mmGFRP

6 oslash 6mmCFRP

G01-GPC50

G01-GPC50

C01-GPC50

C01-GPC50

C02-GPC50

C02-GPC50

C03-GPC50

C03-GPC50G02-GPC50

G02-GPC50

G03-GPC50

G03-GPC50


X



Group SpecimenID

FRPtype




failureb(mm)

h(mm)

G1G01-GPC50



G2C01-GPC50






















Trial G(kgm3)

S(kgm3)

FA(kgm3) M SS AF EW

(kgm3)SP

(kgm3)WBratio


3 days(MPa)

7 days(MPa)

28 days(MPa)



Group SpecimenID






Density(kgm3)

G1

G01-GPC50 4628 3599 481 29066 013 2427

G02-GPC50 4512 3167 492 26691 016 2387

G03-GPC50 4544 3272 446 25771 012 2370

G2

C01-GPC50 4466 3552 493 29582 016 2386

C02-GPC50 4749 4456 533 32272 014 2393

C03-GPC50 4541 4084 553 29582 015 2431

20

25

30

35

40

45

6 8 10 12 14 16

fprime c (M

Pa)

18NaOH molarity

(a)

20

25

30

35

40

45

50

02 025 03 035 04Water-binder

fprime c (M

Pa)

(b)

5

7

9

11

13

15

17

19

21


fprime c (M

Pa)

(c)








Figure 4 Test setup









G1



G2




(a) (b)

(c) (d)

(e) (f )





0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






















Trial G(kgm3)

S(kgm3)

FA(kgm3) M SS AF EW

(kgm3)SP

(kgm3)WBratio


3 days(MPa)

7 days(MPa)

28 days(MPa)



Group SpecimenID






Density(kgm3)

G1

G01-GPC50 4628 3599 481 29066 013 2427

G02-GPC50 4512 3167 492 26691 016 2387

G03-GPC50 4544 3272 446 25771 012 2370

G2

C01-GPC50 4466 3552 493 29582 016 2386

C02-GPC50 4749 4456 533 32272 014 2393

C03-GPC50 4541 4084 553 29582 015 2431

20

25

30

35

40

45

6 8 10 12 14 16

fprime c (M

Pa)

18NaOH molarity

(a)

20

25

30

35

40

45

50

02 025 03 035 04Water-binder

fprime c (M

Pa)

(b)

5

7

9

11

13

15

17

19

21


fprime c (M

Pa)

(c)








Figure 4 Test setup









G1



G2




(a) (b)

(c) (d)

(e) (f )





0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls









Figure 4 Test setup









G1



G2




(a) (b)

(c) (d)

(e) (f )





0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls











G1



G2




(a) (b)

(c) (d)

(e) (f )





0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(a)

0 5 10 15 20 25 30 35 400

20

40

60

80

100

120

140

160

180

Load

(kN

)

Deflection (mm)


(b)


020406080

100120140160180

0 05 1 15 2 25 3 35 4Lo

ad (k

N)

Crack width (mm)

G01-GPC50C01-GPC50

G02-GPC50C02-GPC50

G03-GPC50C03-GPC50







0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C01-GPC50G01-GPC50

(a)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C02-GPC50G02-GPC50

(b)

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40

Load

(kN

)

Deflection (mm)

C03-GPC50G03-GPC50

(c)



0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




0

20

40

60

80

100

120

140

160

180

200

02 06 1 14 18 22 26

Load

(kN

)

ρfρ


(a)

ρfρ

0

5

10

15

20

25

30

02 06 1 14 18 22 26D

eflec

tion

(mm

) at 5

0kN

load

leve

l


(b)


0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(a)

Figure 10 Continued







ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls









ρf Af

bd (1)


ρfb 085β1fcprime

ffu

Ef εcuEfεcu + ffu

(2)



7ge 065 (3)



ρfff

fcprime1113888 1113889 (4)

0

20

40

60

80

100

120

140

160

180

200

ndash0004 ndash0002 0 0002 0004 0006 0008 001 0012 0014 0016 0018 002 0022 0024

Load

(kN

)

Strain (mmmm)


(b)




ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





ff

Efεcu( 11138572

4+085β1fcprime

ρf

Ef εcu

11139741113972




1113888 1113889

β1c Afff

085fcprimeb

(6)



Ie Icr


(7)





Δ (Pa2)

24EcIe3L

2minus 4a

21113872 1113873 (9)



ρfb α1β1fcprime

ffu

EfεcuEf εcu + ffu

(10)




M ρfff bd2 1 minus

ρfff

2α1fcprime1113888 1113889 (13)


clt ffu (14)


c 0 (15)


Δ (P2)L3

24EcIcr3

a

Lminus 4

a

L1113874 1113875

3minus 8η

Lg

L1113888 1113889

3⎛⎝ ⎞⎠ (16)


η 1 minusIcr

Ig (17)








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








Mexp(kNmiddotm)

M ACI(kNmiddotm)

M CSA(kNmiddotm)

Δexp(mm)

ΔACI(mm)


G1G01-GPC50 2308 1902 1898 381 1309 1313 824

742822

826G02-GPC50 4000 3144 3703 563 1184 1441 786 926G03-GPC50 5832 3591 4262 442 987 1142 616 731

G2

C01-GPC50 4500 2885 2872 332 619 651 641663

638737C02-GPC50 6164 4055 4766 625 551 615 658 773

C03-GPC50 6792 4689 5437 537 438 480 691 801Avg () 703 781

0

10

20

30

40

50

60

70

80


Mom

ent o

f res

istan

ce (k

Nmiddotm

)












5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





5 Conclusions













Data Availability




References










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




comparisonoftheflexuralperformanceandbehaviourof fly-ash...

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