research paper structural behavior of modified …structural behavior of modified reactive powder...

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Int. J. Struct. & Civil Engg. Res. 2015 Mohammed M Kadhum et al., 2015

STRUCTURAL BEHAVIOR OF MODIFIED

REACTIVE POWDER CONCRETE BEAMS

REINFORCED WITH REBARS AND STEEL MESH

Mohammed M Kadhum1*, Jamal Saeed2 and Salah J Moham2

1 College of Engineering, Babylon University, , PO Box. 4, Babylon-Hilla, Iraq.

2 College of Engineering, Al-Mustansiriya University, Iraq.

*Corresponding author: Mohammed M Kadhum � [email protected]

ISSN 2319 – 6009 www.ijscer.com

Vol. 4, No. 1, Feburary 2015

© 2015 IJSCER. All Rights Reserved

Int. J. Struct. & Civil Engg. Res. 2015

Research Paper

INTRODUCTION

Concrete structures are being successfully andeconomically reinforced with high-strength,uniformly distributed wires in steel mesh. Thesmaller diameter, closely-spaced wires ofsteel mesh provide more uniform stressdistribution and more effective crack controlin slabs and walls. The wide range of wire sizes

This paper summarizes work carried out to study the influence of using hooked end steel fibersand steel mesh content on the Normal Strength Concrete (NSC) and Modified Reactive PowderConcrete (MRPC) beams. All the beams are simply supported with 1050 mm span and loadedwith two equal concentrated loads. The experimental results indicate that in comparison withconventional concrete (NSC), the ultimate load of unreinforced MRPC beams increases by24.2% and 26.0% when steel fibers are used at 0.5%, and 1.0% by volume, respectively. Theunreinforced RPC beams which contain steel fiber of (0.5% and 1% volume fraction respectively)but they sustained ultimate loads of (385 and 423) kN compared with the (310 and 337) kNultimate load of the unreinforced normal strength concrete beams, and compared with the (410and 435) kN ultimate load of the reinforced normal strength concrete beams with 2% of steelmesh reinforcement. While, the ultimate load of MRPC beams reinforced was 540 kN. Thisindicates that the use of MRPC allows for smaller, thinner, lighter sections to be designed whilestrength is still maintained or even improved and taking advantage by minimizing material usageand cost in addition to reducing the weight of beams.

Keywords: Modified reactive powder concrete, Steel mesh, Steel fiber, RC beams, Deflection,Load carrying capacity

and spacings available makes it possible tofurnish the exact cross-sectional steel arearequired. The welded crosswire hold thereinforcement in the proper position, uniformlyspaced. The ease and speed with which steelmesh can be handled and installedconsiderably reduces placing time, resultingin reduced cost (Mohammed, 2014).

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Reduced construction time is of particularbenefit by affording earlier occupancy andreducing total cost. Material savings can berealized by specifying steel mesh with higheryield strengths as recognized by ACI 318 andASTM. Steel mesh is used successfully inconstruction works and in rehabilitation andstrengthening of reinforced concrete structureswith ferrocement and shotcrete.

Kaleel, 2000 tested eight beams, four ofwhich were with High Strength Concrete (HSC)and the rest were with Normal StrengthConcrete (NSC). All the beams were testedincrementally up to failure before and afterrepairing. The effect of repairing method onthe strength and behavior of beams wasdiscussed. The methods of repairing were:conventional, by welded wire meshes WWMand by steel fibers of 1.0% volume fraction.He recorded that the variation of repairingefficiency is between 92.7-138.9% and 97.5-125% for HSC and NSC, respectively,whereas at a point before yielding the ratio ofrepaired deflection to that of the original variesbetween 74.4-113.3% for HSC and 78.5-103.3% for NSC.

Yao et al. (2008) conducted experimentalinvestigation for the flexural behavior of threereinforced beams exposed to fire andrehabilitated with high-strength steel wire meshand polymer mortar. The Experimental resultsshowed that the flexural load-carrying capacityand stiffness of the fire-exposed RC beamwere reduced. The flexural load-carryingcapacity and stiffness of the strengthenedbeam were increased effectively. The effectof this rehabilitation can reach the level of RC

beams before fire on load-carrying capacity.

Avinash and Parekar (2010) carried out anexperimental investigation to assess thetorsional behavior of SFRC rectangular beamssubjected to combined torsion-bending-shearwith longitudinal and web reinforcement. Thetests were conducted on 20 samples ofprototype and studied for their torsionalresistance for combined loading under torsion-bending-shear. For the tested prototypebeams, all the parameters were maintainedidentical except the three chosen parameters,viz., torsion to moment ratio (T/M), torsion toshear ratio (T/V) and percentage of webreinforcement. The values of aspect ratio andvolume fraction are kept uniform to 60 and0.6%, respectively for all the beams. The studyinvolved the influence of web reinforcement onthe ultimate torsional strength of SFRC beamsunder variable values of T/M and T/V ratios.The test results are compared with a modelfor SFRC beams without reinforcement. Thecomparison reveals that though the ultimatetorsional strength is independent of longitudinalreinforcement, it depends on the spacing(thereby the percentage) of web reinforcement.

Voo et al. (2002) examined manyspecimens of RPC for the two-point flexuraltensile strength obtained on 100 mm squareprisms spanning 400 mm. The steel fibersused in these testes consisted of either 13 mmstraight fibers and/or 30 mm end-hooked fibersand occupied 2% by volume of concrete.Flexural strength up to 30 MPa was obtained.

Two types of concrete mixes are used NSCof 35 MPa compressive strength and MRPCof 90 MPa. Two volume fraction ratios of (0.5

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and 1.0)% with SF and SM are used in thetwo concert types. The MRPC mixesproduction requires high quality materials. Thepresent study is intended to deal with the effectof Reactive Powder Concrete (RPC) and thevolume fractions of the Steel Fibers (SF) andSteel Meshes (SM) on improving the structuralbehavior of reinforced concrete beams throughstrength and stiffness properties in comparisonwith the behavior of conventional reinforcedconcrete with ordinary compressive strengthand without any steel fibers or steel meshes.

EXPERIMENTAL PROGRAM

MATERIALS and METHODS

Effective production of concrete mix isachieved by more stringent requirements onmaterials selecting, controlling andproportioning the entire ingredient. Optimumproportions must be selected according to themix design methods, considering thecharacteristics of all materials used. The main

properties of these materials are as follows:

Cement

Bazian ordinary Portland cement type (I)manufactured in Iraq is used. The chemicalcomposition and physical properties ofthe cement are shown in Tables 1 and 2complying with the Iraqi standard specificationNo. 5 / 1984.

Fine Aggregate

AL–Ukhaidher natural sand is used which hasFineness Modulus (FM) of (2.60), bulk SpecificGravity (SG) of (2.58) and sulfate content(SO3%) of (0.09%) by sand weight, which isless than the limit of Iraqi standardspecification No. 45/1984.

Coarse Aggregate

Crushed gravel from AL-Nibaee with nominalmaximum size of (14 mm) is used. The bulkSG of this aggregate is (2.64) and its gradinga complying with the Iraqi standardspecification No. 45/1984.

Table 1: Chemical Composition of Cement

Chemical Composition Percentage by Weight Limits of IOS No. 5/1984

CaO 63.47 —

Fe2O3 2.85 —

Al2O3 5.46 —

SiO2 19.5 —

MgO 2.44 < 5

SO3 2.11 < 2.8

L.S.F 0.80 0.66 – 1.02

L.O.I 3.12 < 4

I.R 0.73 < 1.5

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Admixture

For the production of MRPC mixes, superplasticizer (high range water reducing agentHRWRA) based on poly carboxylic ether isused. One of the new generation of polymerbased super plasticizer designed for theproduction of SCC Glenium 51 is used; thenormal dosage for Glenium 51 is (0.5-0.8) L/100 kg of cement mass. The typical propertiesare shown in Table 3.

Silica Fume

Silica fume is a highly reactive material that isused in relatively small amounts to enhancethe properties of concrete. The AmericanConcrete Institute ACI234R-96 defines silica

fume as “very fine non-crystalline silicaproduced in electric arc furnaces for silicon oralloys containing silicon”. It is usually a greycolored powder, somewhat similar to Portlandcement or some fly ashes. Silica fume isavailable as a densified powder or in a water-slurry form. It is generally used at 5 to 12% bymass of cementitious materials as a partialreplacement for concrete structure that needhigh strength or significantly reducedpermeability to water (55). In the present work,silica fume has 10% cement mass and thechemical composition of this silica fume isshown in Table 4, which is reported bymanufacture.

Table 3: Typical Properties of Glenium 51

No. Main action Concrete super plasticizer

1 Color Light brown

2 pH. Value 6.6

3 Form Viscous liquid

4 Chlorides Free of chlorides

5 Relative density 1.08 – 1.15 gm/cm3@ 25°C

6 Viscosity 128 ± 30 cps @ 20°C

7 Transport Not classified as dangerous

8 Labeling No hazard label required

Table 2: Physical Properties of Cement

Properties Test Results Limits of IOS No. 5/1984

Fineness using Blaine air permeability apparatus (cm2/gm) 3100 > 2300

Setting time using Vicat’s Method Initial (min) 160 > 45 min

Final (hrs: min) 4:25 < 10 hrs

Soundness using Autoclave Method 0.19% < 0.80%

Compressive strength (MPa) (70.7 mm) at: 3 days 31.2 >15

7 days 34.0 >23

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Steel Fibers

Hooked ends mild carbon steel fibers wereused throughout this work with volume fractionsof (Vsf= 0.5 and 1.0%), Figure 1 show thesample of this steel fiber type. N V BekaertCorporation manufactured this type of steelfibers for steel wire fibers, UAE. The propertiesof the used steel fibers are presented inTable 5.

Steel Mesh

Square welded steel meshes, were used withvolume fractions of (Vmf = 1 and 2%) forstrengthening the side faces of beam samples.Their main properties are shown in Table 6.They fixed to the main steel bars and stirrupsusing steel wires.

Reinforcing Steel

Deformed steel bars of diameter (10 mm) areused for the main reinforcement and steel barsof diameter (6 mm) are used for stirrups. Testresults refer that the adopted steel barsconformed to (ASTM A615-86) in Table 7. Thebars have been tested in the materiallaboratory of the Civil Engineering Departmentat the University Mustansiriyah, Baghdad, Iraq.

Concrete Mixing Procedure

The mixing procedure is an important thing toobtain the required workability andhomogeneity. A horizontal rotary mixer of (0.3

Table 4: Chemical Analysis of the Silica Fume

Chemical Composition CaO Fe2O3 Al2O3 SiO2 MgO K2O+Na2O SO3 L.O.I

Content (%) 0.5 1.4 0.5 92.1 0.3 1.0 0.1 2.8

Limit ASTM C1240 ≥ 85 ≤ 6

Figure 1: Hooked ends Steel Fibers

Table 5: Properties of the Steel Fibers*

Property Relative density Yield strength Average length Nominal diameter Aspect ratio

Specifications 7860 kg/m3 1130 MPa 50mm 0.5mm 100

Note: *Manufacturer Properties

Table 6: Properties of the Steel Meshes

Property Relative density Yield strength Average diameter Opening size

Specifications 7860 kg /m3 410 MPa 1.8mm 23 x23mm

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m3) capacity is used, and the followingsequence is adopted after a number of trialmixes has been done. The mixes are detailedin Table 8.

Mixing NSC

Before starting to mix NSC, it is necessary tokeep the mixer clean and moist but free ofwater. First, the gravel and sand are poured inthe mixer, with the addition of (1/3) of the mixingwater to wet them, and then they are mixed for(1 min). Cement is added at this stage andmixed for (1/2 min), then followed by (1/3) ofmix water and mixed for (1 min), and then theremaining water is added gradually andmixed for (1.5 min). The total mixing time is (4min).

Mixing MRPC

The procedure used for production of theMRPC is briefly stated in the following points:firstly, cement and silica fume are mixedtogether carefully to obtain dry cementitiousmaterial (powder), the fine aggregate is added

to the mixer with 1/3 water, and mixed for 1min. Following, the powder (cement + silicafume) is added with another 1/3 mixing water,and mixed for 1 min. After that, the coarseaggregate is added with the last 1/3 mixingwater and 1/3 of superplasticizer, and mixedfor (1.5) min then the mixture is left for (1.5)min for rest. Then, the remaining 2/3 of thesuper plasticizer is added and mixed for (1.5)min. The mixture is then discharged, cast andtested. The total time of mixing is (5 min).

Adding the Steel Fibers

When steel fibers are required in the above

mixes, the addition of the steel fibers comes

after mixing completion; steel fibers are added

to the wet mix. To avoid balling and to distribute

the steel fibers uniformly, the required amount

of the fibers is gradually added in the mix by

hand sprinkling while the mixer is in motion.

The fresh fibrous concrete has been mixed for

(3 min).

Table 7: Properties of Steel Bars

Nominal Diameter Measured Diameter Modulus of Elasticity Yield Stress Ultimate Stress

(mm) (mm) (Es) (GPa) (fy) (MPa) (fu) (MPa)

10 9.53 200 484 719

6 6.17 200 383 545

Table 8: Mix proportions of Concrete

Mix Notation Nominal Mix Proportions (kg / m3)

Compressive w/c Ratio

Strength(MPa) Water Cement Sand Gravel SP Silica fume

NSC 35 0.43 173 400 600 1200 - -

MRPC 90 0.28 240 800 900 1000 4.0 80

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Details of Beams

Eighteen beams with (180 x 250 x 1200 mm)dimensions and with (ρ = 0.0038) and withspacing between closed stirrups as (100 mm)c/c are used. The spacing of stirrups as wellas the reinforcement ratio and the limitationsof reinforcement according to ACI Code 318-95. All the beams, as shown in Figure 2, aretested under flexural moment.

Load Measurement

The load is applied in two points loading with350 mm spacing between these points asshown in Figure 3, the test continues up tofailure, and this failure mode leads topropagation of diagonal tension cracking in

all the tested beams but flexural crackingappear in some beams with high load carryingcapacity and this is clear in Figure 3. Dial gagehaving accuracy of 0.001 mm per is positionedat the midspan of the tested beam to observeits deflection.

Testing is conducted by using MFL systemof hydraulic universal testing machine typeEPP300, as shown in Figure 4 with a maximumcapacity of (3000 kN). Before testing a thinlayer of white emulsion paint is applied ontothe surface of the specimen to aid the detectionof cracks.

RESULTS AND DISCUSSION

Hardened NSC and MRPC Properties

Figure 2: Details of Beam Specimens

Figure 3: Details of the Tested Beams

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The test results for compressive strength of thebeams investigated in this study aresummarized in Table 9. This table shows thecompressive strength values at two ages, 3and 28 days.

It is obvious from the test results slightincrement compressive strength of concreteby (6.7 and 10.3)% from mixes contain steelfibers (0.5 and 1.0)% volume fractionrespectively relative to the control mix(4)(MRPC without steel fiber).

The static modulus of elasticity results forFR-RPC mixes are presented in Table 9, whichshow slight increases in the static modulus ofelasticity with respect to non-fiber concrete.This increase might be first due to the staticmodulus of elasticity of the steel fibers (eventhough their volumetric ratio in the matrix islow), and secondly due to the transfer of stressfrom the matrix to the fibers by interfacial bondbetween the steel fibers and matrix. The stress

is thus shared by the fibers and matrix, and ahigher load could be applied before the matrixcracks.

It is worthwhile to note that the fibrousconcrete mixes really standout higher in theflexural strength when compared to the non-fibrous concrete mixes of NSC and MRPC. Itcan be seen from the test results that thepercentage increase in modulus of rupture oftwo types of concrete after 28 days of curingat 23oC, relative to that tested after 3 days ofcuring, ranges between (13.2 - 391.2)%.

Load Carrying Capacity

The applied loads and responded deflectionsare listed in Table 10, so, it discussed throughthis work according to type of concrete(compressive strength) effect, steel fiberseffect and steel mesh effect. The loaddeflection curves are graphed to explain theflexural behavior and the stiffness of the tested

Figure 4: The Testing Machine

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beam beside the cracking propagation andmode of failure. The comparisons among thetested beams are adopted to explain the effectof Modified Reactive Powder Concrete(MRPC) in improving the structural behaviorof reinforced concrete beams contain steelfibers and steel meshes.

Figure 5 graphs this value and representsthe development of load carrying capacity forthe tested beams due to difference in theircompressive strength and content of steelfibers and steel mesh.

Type of Concrete Effect on LoadCarrying Capacity

Two types of concrete NSC and MRPC areused in the present work, by comparisonamong the two types, it can be noticed that,the MRPC group of beams is the strongestgroup according to the ultimate carrying loadand followed by the NSC group as shown inFigure 6.

It be concluded that, the load carryingcapacity of the MRPC beams is greater thanthe load carrying capacity of the NSC beamswhen the tested beams have the same contentof steel fibers and steel meshes, but theincrement percentage of the load carryingcapacity of the NSC beams is greater than theincrement percentage of the load carryingcapacity of the MRPC beams under the sameproperties. On the other hand, the maximumincreasing of the load carrying capacity of theMRPC beams against the NSC beams canbe achieved with beams without steel fibersand steel meshes.

Steel Fibers Effect on LoadCarrying Capacity

To observe the effect of steel fibers on the loadcarrying capacity of the test beams of NSCand MRPC groups, Figures 7 and 8 weregraphed for the different steel fibers volumefraction (Vsf) with each constant steel meshesvolume fraction (Vmf).

Table 9: Mechanical Properties of the Studied ModifiedReactive Powder Concrete and Normal Concretes

Steel Compressive Modulus of Modulus of Rupture

Type of Concrete Mix Fibers Strength (MPa) Elasticity (GPa) (MPa)at age (days)

No. % (Vf) at age (days) at age (days)

3 28 3 28 3 28

NSC Mix1 0.0 20.1 35.3 15.89 26.60 4.3 6.8

Mix2 0.5 24.8 39.8 18.27 29.40 6.4 7.7

Mix3 1.0 29.9 44.5 21.88 32.20 6.9 8.9

MRPC Mix4 0.0 57.8 87.7 25.10 37.54 11.3 17.4

Mix5 0.5 67.0 94.0 31.03 46.18 17.9 22.8

Mix6 1.0 73.4 97.8 42.40 53.91 28.5 33.4

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Table 10: Overall Results From Tests

Mix Notation Beam Steel Steel Ultimate Ultimate

Symbol Fibers Meshes Load (Pu) Deflection

(Vsf) % (Vmf) % (kN) (ΔΔΔΔΔu) (mm)

NSC B1 - - 284 3.75

B2 - 1 365 3.28

B3 - 2 385 3.84

B4 0.5 - 310 3.71

B5 0.5 1 380 3.55

B6 0.5 2 410 3.91

B7 1 - 337 3.21

B8 1 1 390 3.09

B9 1 2 435 3.45

MRPC B10 - - 373 3.28

B11 - 1 430 3.14

B12 - 2 465 3.18

B13 0.5 - 385 3.95

B14 0.5 1 470 3.15

B15 0.5 2 500 3.44

B16 1 - 423 3.18

B17 1 1 475 3.11

B18 1 2 540 3.01

From Figures above, the observation leadsto notice that the effect of steel fibers on theincrement percentage of the load carryingcapacity of the NSC beams is greater than thatcorresponding of the MRPC beams in thesame properties.

Steel Meshes Effect on LoadCarrying Capacity

To observe the effect of steel meshes on the

load carrying capacity of the test beams ofNSC and MRPC groups, Figures 9 and 10were graphed for the different steel meshesvolume fraction (Vmf) with each constant steelfibers volume fraction (Vsf).

From these Figures, the observation leadsto notice that the effect of steel meshes on theincrement percentage of the load carryingcapacity of the NSC beams is greater than that

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Figure 5: Load Carrying Capacity of the Tested Beams

Figure 6: Effect of Concrete Type on the Load Carrying Capacity

Figure 7: Effect of Steel Fibers on the Load Carrying Capacityof NSC Beams in Comparison with B

1

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corresponding of the MRPC beams in thesame properties.

It can be concluded that, the effect of steelfibers and steel meshes in MRPC beams haveless activity in comparison with their activity inNSC beams to develop the load carryingcapacity of a specific beam above itsreference.

Type of Concrete Effect onDeflection

By comparison between the two concretetypes NSC and MRPC, it can be noticed that,the MRPC group of beams is the most stiffnessgroup according to less values of deflectionand followed NSC group of beams as inFigures 11 and 12.

Steel Fibers Effect on Deflection

To explain the effect of steel fibers ondeflection for in the present work, the beamswhich without steel meshes content wereselected for graphing the curves of appliedload vs. midspan deflection in Figures 13 and14 for discussion. The three selected beamsin each type of concrete were with steel fibers

fraction (Vsf) equals (0, 0.5 and 1)%respectively.

By comparison between the Figures 13 and14, it is clear that the effect of the steel fibersfor decreasing the deflection in MRPC beamsis greater than its effect in NSC beams andmeans more obtained stiffness in the MRPCbeams.

Steel Meshes Effect on Deflection

To explain the effect of steel meshes ondeflection for in the present work, the beamswhich without steel fibers content wereselected for graphing the curves of appliedload vs. midspan deflection in Figures 15 and16 for discussion. The three selected beamsin each type of concrete were with steelmeshes fraction (Vsm) equals (0, 1 and 2)%,respectively.

By comparison between the Figures above,it is clear that the effect of the steel meshes fordecreasing the deflection in MRPC beams isgreater and more effective than its effect inNSC beams and means more obtainedstiffness in the MRPC beams.

Figure 8: Effect of Steel Fibers on the Load Carrying Capacityof MRPC Beams in Comparison with B

10

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Figure 9: Effect of Steel Meshes on the Load Carrying Capacityof NSC Beams in Comparison with B

1

Figure 10: Effect of Steel Meshes on the Load Carrying Capacityof MRPC Beams in Comparison with B

10

Figure 11: Applied Load Vs. Midspan Deflection of NSC Beams

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Figure 12: Applied Load Vs. Midspan Deflection of MRPC Beams

Figure 13: Effect of Steel Fibers on the Deflection of NSC Beams

Figure 14: Effect of Steel Fibers on the Deflection of MRPC Beams

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Mode of Failure

It is clear from the load-deflection curves ofitems 4.3 above that, the general behavior ofall the tested beams was the sameapproximately, and also from Figure 17 canbe noticed the pattern of cracking propagationwhich was generally the same for all the tested

beams. However, almost tested beams failedby diagonal tension cracks extended from nearthe support toward the point load. The prevalentmode of failure can be transformed to flexuremode of failure represented by vertical cracksextended in the middle of the beam from lowerto the upper face, and that can be achieved by

Figure 15: Effect of Steel Meshes on the Deflection of NSC Beams

Figure 16: Effect of Steel Meshes on the Deflection of MRPC Beams

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Figure 17: Cracking Pattern of the Tested Beam Specimens

using MRPC to increase the compressivestrength of the section in addition to increasethe content of the steel fibers and steel meshes.

CONCLUSION

Based on the results from the experimental

works the following conclusions can be drawn.It is emphasized that these conclusions arelimited to the variables studied:

1. It was found from experimental results thatthe use of hooked ends steel fibers inMRPC and NSC mixes significantly

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improves the following properties:

• Increase of the compressive strength.

• Improvement of Modulus of Rupture.

• Increase the Ultimate load carrying capacity.

• Increase the stiffness.

• Reduce the crack width and crack spacing.

• As a result decrease the deflection.

2. The rate of improvement of load carryingcapacity and deflection due to steel fibersand meshes in NSC beams is greater thanthat rate in MRPC beams (in case ofcomparison with a reference in eachgroup). But the value of improvement inMRPC is greater than that of NSC (in caseof comparison with the weakened beam).

3. The highest ultimate load carrying capacitycan be satisfied in MRPC by using steelfiber 1% and steel mesh 2%. (B18).

4. The value of deflection was approximatelythe same when using 1% and 2% of steelmesh in NSC, without steel fiber (B2 andB3), but the value of deflection was clearlydifferent when using 1% and 2% of steelmesh in MRPC, without steel fiber .

REFERENCES

1. ACI Committee 318 (1995), “Buildingcode requirements for structural concrete(ACI 318M-95) and Commentary (ACI318RM-95)”, American ConcreteInstitute, Farmington Hills, Michigan, p.371.

2. Avinash S P and Parekar R S (2010),“Steel fiber reinforced concrete beamsunder combined torsion-bending-shear”,Journal of Civil Engineering (IEB), Vol.38, No. 1, pp. 31-38.

3. Collepardi S, Coppola L, Troli R, andCollepardi M (1997), “Mechanicalproperties of modified reactive powderconcrete”, In: V-M Malhotra Ed.Proceedings fifth CANMET/ACIInternational conference on Super-plasticizers and the Chemical Admixturesin Concrete, Rome. Italy. Farmington Hills,MI: ACI publication SP-173, pp. 1-21.

4. Iraqi Organization of Standards, IOS 45(1984), “Aggregate from natural sourcesfor concrete and construction”, Ministry ofPlanning Central Organization forStandardization and Quality Control.

5. Iraqi Organization of Standards IOS 5(1984), Portland cement. Ministry ofPlanning, Central Organization forStandardization and Quality Control. IraqiOrganization of Standards, IOS 5 (1984),Portland cement, Ministry of Planning,Central Organization for Standardizationand Quality Control.

6. Kaleel M A (2000), “Flexural behavior ofrepaired high and normal strengthreinforced concrete beams”, M.Sc.Thesis, University of Technology, Iraq,Jan., p. 92.

7. Mohammed S J (2014), “Structuralbehavior of modified reactive powderconcrete beams reinforced with rebarsand steel mesh”, M.Sc. Thesis, CivilDepartment, College of Engineering, Al-Mustansiriya University, Baghdad, Iraq, p.77.

8. National Ready Mixed ConcreteAssociation (2000), “What, Why andHow? Supplementary cementitious

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materials”, Concrete in Practice, CIP 30,USA, pp. 1-2.

9. Noghabai K (2000), “Beams of fibrousconcrete in shear and bending:experimental and model”, ASCE-Journalof Structural Engineering, Vol. 126, No.2, February, pp. 243-251.

10. Spasojevic A Burdet O Muttoni A (2008),“Structural applications of ultra-highperformance fiber-reinforced concrete tobridges”, Structural concrete laboratory ofthe EcolePolytechnique Federal deLausanne (EPFL), Lausanne,Switzerland. October, PP. 33-41.

11. US Department of Transportation (2005),

“Silica fume user’s manual”, Federal

Highway Administration, April, p. 183.

12. Voo Y L, Foster S J, and Gilbert I R

(2002), “Shear strength of fiber reinforced

reactive powder concrete girders without

stirrups”, UNICIV Report R – 421, School

of Civil and Environmental Engineering.

The University of New South Wales,

UNSW, Sudney, Australia, p. 8.

13. Yao Z H, Huang S M, Yao Q L and Song

B (2008), “Study on Flexural behavior of

fire-exposed RC beams strengthened

with SMPM”, The 14th World Conference

on Earthquake Engineering October 12-

17, Beijing, China, p. 6.

research paper structural behavior of modified …structural behavior of modified reactive powder...

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