research article experimental investigation on use of

Research ArticleExperimental Investigation on Use of Wheat Straw Ash andBentonite in Self-Compacting Cementitious System

Rao Arsalan Khushnood12 Syed Ali Rizwan2 Shazim Ali Memon3

Jean-Marc Tulliani4 and Giuseppe Andrea Ferro1

1Dipartimento di Ingegneria Strutturale Edile e Geotecnica (DISEG) Politecnico di Torino Corso Duca Degli Abruzzi 2410129 Torino Italy2Department of Structural Engineering NUST Institute of Civil Engineering (NICE) National University of Sciences and TechnologySector H-12 44000 Islamabad Pakistan3Department of Civil Engineering COMSATS Institute of Information Technology University Road 22066 Abbottabad Pakistan4Dipartimento Scienza Applicata e Tecnologia (DISAT) Politecnico di Torino Corso Duca Degli Abruzzi 24 10129 Torino Italy

Correspondence should be addressed to Rao Arsalan Khushnood rao nustyahoocomand Shazim Ali Memon shazimalimemongmailcom

Received 2 October 2014 Accepted 13 November 2014 Published 17 December 2014

Academic Editor Mohd Sapuan

Copyright copy 2014 Rao Arsalan Khushnood et alThis is an open access article distributed under theCreativeCommonsAttributionLicense which permits unrestricted use distribution and reproduction in anymedium provided the originalwork is properly cited

In this research we evaluated the feasibility of wheat straw ash and bentonite (raw and heated at 150∘C for 8 hrs) as secondaryraw materials in self-compacting paste (SCP) The fresh and hardened properties of SCP formulations including water andsuperplasticizer demand flow behavior compressive and flexural strength development water absorption and acid attackresistance were evaluated Moreover porosity microstructural and mineralogical investigations were also carried out on SCPformulations Test results showed that the properties of SCP formulations in fresh state depend on the morphology of secondaryrawmaterials For heated bentonite and wheat straw ash formulations the 28 days of compressive and flexural strength were higheror almost similar to reference SCP formulation Among SCP formulations wheat straw ash formulation was found to be moreeffective in consuming free lime and showed significant decrease in porosity with time which in turn improved the resistance ofthis SCP formulation against water absorption and acid attack Based on the test results it can be concluded that the successfulutilization of wheat straw ash and bentonite SCP formulations will offer durable and environmental friendly option to constructionindustry

1 Introduction

Self-consolidating concrete (SCC) is by definition a concretethat completely fills the formwork under its own weightwhile maintaining homogeneity and without any need forconsolidation It deforms under its own weight as a fluiddoes and holds the particles of all sizes without letting themsegregate into ingredients High deformability and segrega-tion resistance are the two primary properties of SCC Highdeformation is achieved by using efficient superplasticizerand high segregation resistance is achieved by using eitherlow waterpowder ratio or moderate waterpowder ratiowith viscosity enhancing agent Various pozzolanic and non

pozzolanic materials such as lime stone powder [1 2] fly ash[3] silica fume [4] metakaolin [5] rice husk ash [6] andbagasse ash [7] have been used by many researchers in SCCformulation Some of them are presented here

Bosiljkov [1] investigated the influence of nonpoz-zolanic fillers (finely ground limestone and crushed lime-stone dust) on the fresh and hardened properties of SCCmixes Test results showed that finer and better-gradedlimestone dust significantly enhances the deformability ofthe paste Moreover it was found out that with high fillervolume the required SCC properties were achieved at lowerwater(cement + filler) ratio Rizwan and Bier [8] carriedout investigation on blends of limestone powder and fly ash

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2014 Article ID 832508 11 pageshttpdxdoiorg1011552014832508

2 Advances in Materials Science and Engineering

on the response of self-compacting mortars (SCM) in freshand hardened states It was found that SCM using blendedraw materials improved the overall response than thoseusing either of them The durability of SCC prepared withmetakaolin and silica fume in replacement mode was investi-gated by Hassan et al [4] According to the test results highlydurable SCC mixtures were obtained using high metakaolincontent with an optimum replacement percentage of around20 Furthermore it was found out that the durability of SCCmixtures prepared with higher MK content was superior toSCC containing silica fume

Several researchers have evaluated the feasibility of usingwheat straw ash (WSA) and bentonite in normal concrete[9ndash11] However the data regarding utilization of WSA andbentonite in self-compacting paste (SCP) to the best ofour knowledge is scarce or nonexistent This research wastherefore carried out to evaluate the feasibility of WSAand bentonite self-compacting paste formulations The SCPformulations were prepared with 10 replacement level Thisreplacement level was chosen because a smaller amount ofsecondary raw material (SRM) results in optimum efficiencyand gives a large increase in strength while the use of largeamount has a smaller effect [12] The successful utilization inprevailing environment will offer multiple benefits includingcost effective solution to construction industry and reducedenvironmental and health issues and would have positiveimpact on the durability of the system

2 Wheat Straw and BentonitePotential-Global and Pakistan Statistics

Wheat is one of the primary sources of food for 245 billionpeople [13] In 2014 the annual global production of wheatwas around 705million tons out of which 75was producedby 18 countries while around 20 was produced by EU-27[14] According to the statistical data [14] Pakistan is rankedat 7 with 35 share to the world wheat production As perPan and Sano [15] the average yield of straw is around 13ndash14 kg per kg of grainThis places the global estimate of wheatstraw at around 534 million tons and for Pakistan this valueis around 1846million tonsThe current use of this abundantsupply of wheat straw as described by Zhang et al [13] is lim-ited to feeding stuff [16] pulp and paper [17] nanomaterials[18] bioethanol [19] fertilizer [20] and construction of mudhouses However in some parts of the world and especiallyin underdeveloped and developing countries wheat straw isburnt in open field causing environmental issues and healthproblems Huge amount of ash obtained after burning ofwheat straw probably has no use and getting rid of it is alsoa problem This research therefore evaluates the feasibility ofusing WSA in SCP formulations

As far as bentonite is concerned the total world produc-tion of bentonite has increased from 133 million tons in 2004[21] to 155 million tons in 2011 [22] while Pakistanrsquos annualproduction has increased from 6154 tons in 2004 [21] to30840 tons in 2011 [22] Moreover Pakistan has millions oftons of bentonite reserves [9] This research therefore alsoevaluates the feasibility of using bentonite (raw and heated)in SCP formulations

3 Experimental Investigation

31Materials andMix Proportion Locally availableOrdinaryPortland Cement (OPC) grade 425R in conformity withASTM C150 [23] was used Bentonite clay was collectedfrom Jehangira situated at 33∘5910158405610158401015840 latitude and 72∘1210158404710158401015840longitude according to Survey of Pakistan topographic sheet43 C1 [10] and it was studied in raw and heated conditionsHeat treatment was given at 150∘C [9] for 8 hrs and the claywas ground according to the procedure mentioned in [10]The powder was then sieved through number 200 standardmesh and resulting sample was used for SCP formulationsWSA was obtained by burning wheat straw available in 1ndash5 cm length The burning of wheat straw was carried outfor 5 hrs in a temperature controlled electric furnace havingsmoke vent at the top During the entire burning processtemperature was maintained at 670∘C as reported to bequite effective to attain good pozzolanic properties [11]For all SCP formulations bentonite and WSA were usedin replacement mode by 10 weight of cement A thirdgeneration polycarboxylate ester based powder type super-plasticizer Melflux 2651 was used to achieve flow level of 30 plusmn1 cm as measured by Hagermanrsquos mini slump The followingspecimen designations were used for SCP formulations

CEM represents reference SCP formulationC + 10 WSA represents SCP formulation with 10wheat straw ashC + 10BN (H) represents SCP formulationwith 10heated bentoniteC + 10 BN(R) represents SCP formulation with 10raw bentonite

32 Mixing Regime Hobart Mixer (5 L capacity) was usedfor mixing SCP formulations Various mixing regimes [24]arementioned in the literature however after experimentingthe following was adopted The constituents were manuallymixed in dry state for 1-2minutes followed by feeding into thebowl the dry mixture along with the requisite mixing waterpredicted by water demand test A slowmixing (145 rpm) wasdone for 60 seconds followed by fast mixing (285 rpm) for120 seconds [25] The total mixing time was 3 minutes (180seconds) for all SCP formulations

33 Testing of Specimens The particle size surface areaand surface morphology of powdered WSA and bentonitesamples were determined by using Laser Granulometer(Coulter LS 230) Brunauer-Emmett-Teller (Finesorb-3010)and Environmental Scanning Electron Microscope (XL 30ESEM FEG) For chemical composition X-ray fluorescence(JSX-3100RII) technique was used The physical propertiesand chemical composition results of powdered samples arerepresentative of three samples

The water demand and setting times of reference SCP aswell as those containing 10 SRM (in replacement mode)were determined by Vicat apparatus at 20 plusmn 1∘C and 20 plusmn 5relative humidity The superplasticizer amount required fora target flow of 30 plusmn 1 cm was obtained for all formulations

Advances in Materials Science and Engineering 3

using Hagermanrsquos mini slump cone having dimensions of 60times 70 times 100mm3 Moreover the flow behavior of SCP systemswas characterized byHagermanrsquosmini slump cone spread andby V funnel time The details of the test can be found in [8]It needs to be pointed out here that the properties of SCP infresh state represent the average of three specimens

The flexural and compressive strength tests were carriedout as per ASTM C 348 [26] and ASTM C 349 [27] respec-tively Flexural strength of SCP formulation is the average ofthree 40 times 40 times 160mm3 specimens while the compressivestrength test was done on broken halves after flexural testsand strength represents the average of six specimens Forwater absorption ASTM C 642-04 [28] was followed whilefor acid attack test procedure mentioned by Rawal [29] wasadopted Three samples each were tested to determine thewater absorption and acid attack test

The porositymicrostructure andmineralogical phases ofSCP formulations were investigated using mercury intrusionporosimetry (MIP) scanning electron microscopy (SEM)and X-ray diffraction (XRD) at the age of 1 and 7 days ForSEM and MIP two small pieces (approx 1 times 1 cm2) extractedfrom compression test were immediately immersed in ace-tone to stop further hydration in the surface zone and cleanedfrom free particles produced during fracture in an ultrasonicbath The specimens were then submerged in isopropanol toremove traces of acetone left in the small pieces [30] ForSEM observations the specimens were further treated forpreparations normally performed including vacuum dryingand gold coating while for MIP the samples were dried inoven at 105∘C for 24 hrs before testing Moreover for MIPthe contact angle of 140∘ was selected For XRD two to threesmall pieces obtained from compressive tests were groundand the powdered samples were used for obtaining XRDdiffractograms in the 5ndash70∘ 2120579 range

4 Results and Discussions

41 Characterization of Powdered Samples

411 Physical Properties and Chemical Composition of Pow-ders The physical properties and chemical composition ofpowders are shown in Table 1 The average particle size ofbentonite is around one-fifth of the average cement particlesize Thus it has comparatively large surface area It can beseen that heat treatment is effective in reducing the moisturecontent of bentonite It is believed that the loss of moisturemight have increased the internal porosity of bentonite andthus resulted in increased surface area Metha and Monteiro[31] described that heat treatment can improve the reactivityof natural pozzolans in cement paste and resultantly enhancecertain properties of concrete It is worth mentioning herethat both the raw and heated bentonitemeet the requirementsof chemical composition of natural pozzolan as laid down inASTM C 618-01 [32]

The chemical composition of WSA shows SiO2and K

2O

as major constituents According to Biricik et al [11 33]the chemical composition of WSA depends upon numberof factors such as type of soil for growing wheat plant thetype of fertilizers used environment burning temperature

burning volume and duration of burning Visvesvaraya [34]pointed out that SiO

2content in WSA is dependent on soil

and environmental conditions existed during development ofwheat crop

412 Surface Morphology by Scanning Electron Microscopy(SEM) and Mineralogical Composition by XRD Analysis Thesize shape and texture of SRMs are important parametersto understand the response of SCP formulations The micro-graphs of bentonite (raw and heated) andWSA are presentedin Figure 1 Bentonite particles show layered structure whichattracts and binds water molecules to its vast inner andouter surface area The layered structure would also requirea higher dosage of superplasticizer to overcome internalfriction during flow It can be seen that particles of rawbentonite show agglomeration due to the presence of internalmoisture whereas heated bentonite particles in general areseparated It can also be seen that the average particle sizeof bentonite clay ranges from 3 to 5 120583m which confirmsthe value given in Table 1 by laser technique As far as themicrographs ofWSA are concerned the shape of the particlesvaries from angular to flat and elongated while the textureappears to be rough and abrasiveThemicrograph also showsthat the particles contain surface pits All these in turnwould increase the water demand of the SCP system to attainconsistency

TheXRD of bentonite (raw and heated) andWSA is givenin Figure 2 The heated and raw bentonites are composedof quartz illite montmorillonite and clinochlore Moreoverthe heated bentonite seems to be relatively less crystallinethan the corresponding raw form As far as WSA sample isconcerned it possesses a large amorphous portion accompa-nied by minor traces of quartz and cristobalite Furthermoretraces of kyanite were also found

42 Fresh and Hardened Properties of SCP Formulations

421 Water Demand Superplasticizer Demand and SettingTime The water and superplasticizer demands as well assetting times of SCP formulations for a target flow of30 plusmn 1 cm [25] are presented in Table 2 In comparison toCEM both bentonite and WSA SCP formulations showedhigher water and superplasticizer demand For bentonitethe higher water and superplasticizer demand are due tothe larger surface area arising from smaller particle size andlayered structure which attracts and binds water moleculesIn addition in comparison to raw bentonite heated bentoniteshowed higher water and superplasticizer demand Duringthermal treatment internal moisture from bentonite wasextracted resulting in larger surface area and hence increasedwater and superplasticizer demand Also the results reportedare in line with the available literature on bentonite used innormal cement concrete [9 35] As far as WSA is concernedthe increase in water demand with respect to CEM is dueto particle shape (angular to flat and elongated) texture(rough and abrasive) and larger surface area For autoclavednormal cement mortar prepared with WSA Al-Akhras andAbu-Alfoul [36] reported decrease in flow table values withincreasing WSA replacement by weight of cement Thus


Table 1 Physical and chemical properties of powders

Parameters Cement (425R) WSA Bentonite (H) Bentonite (R)Physical properties

Mean particle size (120583m) 2200 1230 432 475Surface area (cm2g) 1650 3200 4800 2535Specific gravity 310 230 279 282Moisture content () 290 mdash 005 320

Chemical analysis ()SiO2 1715 7395 5396 4938TiO2 032 192 093 185Al2O3 560 091 2027 1754Fe2O3 321 115 892 1024MgO 144 183 402 380CaO 6409 521 705 954K2O 119 1151 393 483

Strength activity index (SAI)lowast7 days 100 96 94 7726lowast28 days 100 104 99 8518lowastSAI ge75 of CEM (ASTM C618)

suggesting increase in thewater demandofWSAmixes It willbe pertinent to mention here that SCM formulations usingfly ash require less water and superplasticizer demand fora specific target flow The lesser water and superplasticizerdemand of fly ash formulations are due to their sphericalshaped particles which during flow roll over one anotherreducing the internal friction [37 38] However for specifictarget flow SCMSCC formulations prepared with limestonepowder (LSP) and metakaolin (MK) require more water andsuperplasticizer [4 5 8 25]Thehigher demand for LSP is dueto their irregular rough and patchy particle characteristicswhile for MK the layered structure provides sites for internalfriction during flow The results of setting time presented inTable 2 show increase in the setting time of SCP formulationswith addition of WSA and bentonite The increase in thesetting time of SCP formulations varies according to theindividual characteristics of each SRM used

422 Flow After establishing the water demand superplas-ticizer demand and the setting times the next parameterinvestigated for SCP formulations was flowabilityThe resultsof Hagermanrsquos mini slump cone time for a spread of 25 cm(T25 cm) and V funnel time of various formulations areshown in Figure 3 In T25 cm cone flow time mostly internalfriction has to be overcome during unconfined flow of self-compacting paste while in V funnel time both internaland external frictions (between self-compacting paste andgradually reducing funnel section) are present which increasethe overall friction and thus the flow time [8] Increase inT25 cm and V funnel time of SCP formulations containingbentonite and WSA indicate higher friction offered duringflow For the case of bentonite friction was offered by thelayered structure while for WSA it is angular to flat andelongated shape rough and abrasive texture and small surfacepits were possible sites providing friction In addition thepresence of internal free moisture in raw bentonite and its

comparatively lesser surface area than ldquoheatedrdquo bentonite(Table 1) indicates that more effective water is available inthe system to help the flow This makes the former SCPformulation less viscous than the latter In summary the flowof SCP formulation depends heavily on surface morphologyand its internal porosity in addition to other influencingfactors like mixing regime sequence of admixtures additionand watersuperplasticizer contents

423 Strength Activity Index (SAI) As per ASTM C618 SAIat 7 and 28 days should be 75 of the reference cement mixSAI results presented in Table 1 show that all the specimensmeet the requirements of ASTM C618 [32] The mixes showhigher rate of reactivity at 28 days than at 7 days suggestingincrease in the reactivity rate It can thus be inferred that OPChydration and pozzolanic reaction have contributed to higherstrength development rate of the SCP formulations Mirza etal [9] found out that Karak bentonite heated at 150∘C for 3 hrshad higher SAI than control and all other heated bentonites(250∘C 500∘C 750∘C and 950∘C)

424 Compressive and Flexural Strength The compressiveand flexural strength results are shown in Figure 4 Up tothe age of 7 days the CEM SCP formulation showed highercompressive and flexural strength than SCP formulationscontaining WSA and bentonite According to the availableliterature [31 39] the strength gain in mixes containingpozzolan is generally slow at early ages However at 28days the SCP formulations with WSA and heated bentoniteshowed higher or almost similar compressive and flexuralstrength thanCEMThe increase in strength can be attributedto pozzolanic reaction that takes place at a slower rate thanthe hydration of cement better pore refinement effect fillereffect and SRMrsquos particle characterization It is reported [8]thatmargin of strength increase is dependent upon the degreeof pozzolanic activity of the SRM used


Agglomerates

5120583m

(a)

1120583m

(b)

Still some agglomerates

5120583m

(c)

1120583m

(d)

5120583m

(e)

Surface pits

1120583m

(f)

Figure 1 Micrographs of (a b) raw bentonite (c d) heated bentonite and (e f) WSA samples

Table 2 Water demand superplasticizer demand and setting time of SCP formulations

Formulation Water demand (mass of cement) Superplasticizer demand (mass of cement) Setting time (min)Initial Final

CEM 28 0146 225 310C + 10WSA 36 0260 270 365C + 10BN (H) 33 0320 260 360C + 10BN (R) 32 0270 265 370

425 Water Absorption Water absorption results are pre-sented in Figure 5 In comparison to CEM SCP formulationscontaining WSA and bentonite showed decreased waterabsorption It is due to the fact that the reaction between thesepozzolans and calcium hydroxide from hydrated cementpaste is lime consuming In addition it would be shown laterthat these pozzolans are effective in reducing the porosity

of the system which in turn improves the durability of thesystem

426 Resistance toAcidAttack Resistance against acid attackof SCP formulations with and without SRM was measuredin terms of percentage reduction in weight and strength afterimmersing the samples in 5 percent hydrochloric acid and


0 10 20 30 40 50 60 70

Inte

nsity

Wheat straw ash (WSA)

Heated bentonite (BN(H))

Raw bentonite (BN(R))

QC

CQ K

Cl QMI

Q

QM

I

QCl

Cl I Cl MQ

Q

IM Q Q

2120579 (deg)

C cristobalite SiO2 syn tetragonal

K kyaniteAl2SiO5 syn triclinicQ quartz SiO2 syn hexagonalM montmorilloniteNa02 Ca01Al2Si4O10(OH)2(H2O)10

synmonoclineI illiteK06 (H3O)04 Al13Mg03 Fe2+01Si35O10(OH)2 middot(H2O)

Cl clinochloreMg375 Fe2+125Si3Al2O10(OH)8 synmonocline(

synmonocline

Figure 2 XRD of powdered WSA and bentonite (heated and raw)samples

0

05

1

15

2

25

3

35

4

T25 Funnel time

Tim

e (s)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

Figure 3 Flowability (T25 cm time and V funnel time) of SCPformulations

5 percent sulfuric acid solutions for 14 and 28 days Theresults are presented in Figure 6 The weight loss observedin the SCP formulations was due to the loss of cohesivenessof the cement hydration products [31] It can be seen that theamount of weight loss was maximum for CEM in both of theacid solutions The poor performance of CEM against acidattack is due to the fact that it releases considerable portionof free calcium hydroxide that reacts with the acid and asoft and mushy mass is left behind For SCP formulationscontaining pozzolans the free calcium hydroxide reacts withsilica present in the mix to form secondary silica gel and thusreduces the amount of free calcium hydroxide This in turnmade the SCP formulations more durable In addition thelower loss in WSA mix was due to the relatively high content

0

10

20

30

40

50

60

70

80

1 day 3 days 7 days 28 days

Com

pres

sive s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(a)

0

5

10

15

20

25


Flex

ure s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(b)

Figure 4 Variation in (a) compressive strength (b) flexure strengthof SCP formulations

2

21

22

23

24

25

26

27

28

29

Formulations

Wat

er ab

sorp

tion

()

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

Figure 5 Water absorption of SCP formulations at 28 days

of silica present in the mix for reaction with free calciumhydroxide and thereby making it more durable It is worthmentioning that the amount of secondary C-S-H gel andsubsequent reduction in free calcium hydroxide is dependenton the percentage of pozzolan in the mix It can also be seenthat more deterioration was caused by sulfuric acid than byhydrochloric acid It is due to the fact that in case of sulfuricacid a product called calcium sulfoaluminate hydrate alsoknown as ettringite [Ca

6Al2(SO4)3(OH)12sdot26H2O] is formed

which expands and hence causes disruption of the set cement


0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)

Figure 6 Effect of (a) HCl (b) H2

SO4

on the weight loss of SCP formulations

0

5

10

15

20

25

30

Flexure strength Compressive strength

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4

on the strength loss of SCP formulations at 28 days

paste [31] whereas no such product is formed in case ofhydrochloric acid

The results of compressive and flexure strength afterexposure to HCl and H

2SO4are presented in Figure 7 CEM

SCP formulation showed maximum strength loss For HClimmersion the loss in compressive and flexure strength wasup to 21 and 28while for H

2SO4immersion the loss was up

to 41 and 44 respectively It can also be seen that WSA SCPformulation showed better performance It would be shownlater that the WSA SCP formulation was more effective inconsuming free lime Moreover the improved performanceof WSA SCP formulation was due to lowest porosity andaverage pore radius as determined by MIP Based on the testresults it can be deduced that these SCP formulations canbe used in acidic environment such as chemical industriessewer pipes foundations in ground waters containing highconcentration of sulfates and near sea water

427 Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy of SCP Formulations The micrographs ofSCP formulations at the age of 1 and 7 days along with oxide

composition extracted from EDX are displayed in Figure 8and Table 3 All formulations showed the growth of ettringitein the form of needle-shaped crystals hexagonal-prismaticcrystals of calcium hydroxide and calcium silicate hydrate(C-S-H) The oxide analysis of cement paste prepared withWSA and bentonite showed reduction in the content of CaOthus testifying the efficiency of these pozzolans in reducingcalcium hydroxide and transforming it into secondary C-S-H gel It can also be seen that WSA is more effective inconsuming CaO and thereby producing SCP formulationwith improved mechanical properties and durable systemHowever it should be noted here that for cementitioussystems the analysis appeared to be of just qualitative natureand definite quantitative results should not be expected dueto large point to point variation in cement based materials

428 Mercury Intrusion Porosimetry (MIP) of SCP Formula-tions The porosity and pore size distribution were measuredusing MIP The results are reported in Table 4 The resultsclearly indicate decrease in porosity and average pore radiuswith age A significant decrease in porosity and average


1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite

Portlandite20120583m

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite

Bentonite (R)agglomorate

7 days

5120583m

Mg

times3000

(h)

Figure 8 Micrographs of hydration products along with EDAX of (a b) CEM (c d) C + 10 WSA (e f) C + 10 BN(H) and (g h) C +10 BN(R) at 1 and 7 days

pore radius was observed by the addition of pozzolans ascompared to reference SCP formulation This is one of thereasons contributing to better mechanical and durabilityperformance of these pozzolans SCP formulations AmongSCP formulations containing pozzolan WSA formulationshowed lowest porosity and average pore radius at the age of 7daysThis explains whyWSA SCP formulation showed better

mechanical and durability performance among all other SCPformulations

43 XRD Analysis of SCP Formulations The mineralogicalanalysis by XRD in the 2120579 range from 5 to 70∘ was carriedout to detect changes in the hydration products due to thepresence of WSA raw and heated bentonites at the age of


0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day

H hatruriteCa3SiO5 syn trigonalL larniteCa2(SiO4) synmonoclineP portlanditeCa(OH)2 syn hexagonal

E ettringiteCa6Al2(SO4)3(OH)12 26(H2O) syn hexagonalmiddot

(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)

Figure 9 XRD of SCP formulations at (a) 1 day (b) 7 days

Table 3 Variation in oxide composition of SCP formulations at 1 and 7 days

Oxides CEM C + 10WSA C + 10BN (H) C + 10BN (R)1 day 7 days 1 day 7 days 1 day 7 days 1 day 7 days

CaO 5584 5935 5832 4959 5429 4806 5524 5218SiO2 2316 878 2532 887 2924 950 2524 980SO3 734 1744 675 2330 849 1975 749 2215Al2O3 792 1343 729 1412 759 1525 683 1445Fe2O3 128 357 452 159 280 155 440 169K2O 120 106 068 071 132 122 108 105MgO 248 040 119 056 129 052 210 062

Table 4 Pore sizes and total porosity of SCP formulations at 1 and 7 days

Sample ID Avg pore radius (nm) Max pore radius (nm) Total porosity () Porosity ()(diameter le100 nm)

Porosity ()(diameter ge100 nm)

1 dlowast 7 d 1 d 7 d 1 d 7 d 1 d 7 d 1 d 7 dCEM 185 102 567285 573557 153 166 454 682 546 318C + 10WSA 194 57 570114 529456 175 125 437 845 563 155C + 10BN (R) 202 71 555725 561692 201 135 443 813 557 187C + 10BN (H) 197 65 556534 545216 184 126 429 784 571 216lowastldquodrdquo denotes number of days

1 and 7 days The XRD patterns of hydrated cement pasteprepared with and without SRM are shown in Figure 9The reduction in the diffraction peaks of calcium hydroxidein WSA and heated bentonite SCP formulations indicatesthe efficiency of these materials as pozzolan The reductionof calcium hydroxide in these mixes is also responsiblefor improved compressive and flexural strength and betterresistance against water absorption and acid attack In addi-tion all SCP formulations showed the presence of ettringite

[Ca6Al2(SO4)3(OH)12sdot26(H

2O)] hatrurite [Ca

3SiO5] and

larnite [Ca2(SiO4)] at 1 and 7 days

5 Conclusions and Recommendations

This research work evaluated the effect ofWSA and bentonite(raw andheated) on the overall response of SCP formulationsThe characterization of SRMs is essential as they affect waterdemand superplasticizer demand flow behavior strength


durability microstructure and mineralogy of SCP formu-lations Based on experimental investigations the followingconclusions can be drawn

(i) Bentonite andWSA SCP formulations showed higherwater and superplasticizer demands For bentonitethe increase in demand is due to larger surfacearea arising from smaller particle size and layeredstructure while forWSA the increase is due to particleshape texture and larger surface area In additiondue to individual characteristics of each SRM the SCPformulations showed increase in flow time indicatinghigh friction offered during flow

(ii) The pozzolanic SCP formulations showed better per-formance than reference SCP formulation due toreaction of these pozzolans with free lime whichenhances the mechanical and durability performanceby reducing free lime content

(iii) Among all SCP formulations WSA formulationshowed the best mechanical and durability perfor-mance due to better free lime consuming abilityand reduced porosity of the system Moreover incomparison to raw bentonite heat treated bentoniteat 150∘C improved the mechanical and durabilityperformance of SCP formulations

(iv) The utilization of WSA and bentonite in SCP formu-lations provides cost effective durable and environ-mental friendly option to construction industry

It is suggested that further research should be carried outto evaluate the long-term performance of these SRMs withdifferent replacement levels in self-compacting paste systemThe long-term performance includes strength durabilitymicrostructural and mineralogical analyses In additiondetailed studies should be carried out on self-compactingmortar and concrete prepared with these SRMs

Abbreviations

BN BentoniteCEM Reference self-compacting paste formulationEDX Energy dispersive X-ray spectroscopyLSP Lime stone powderMK MetakaolinMIP Mercury intrusion porosimetryOPC Ordinary Portland CementSCP Self-compacting pasteSCM Self-compacting mortarSCC Self-consolidating concreteSAI Strength activity indexSEM Scanning electron microscopySRMs Secondary raw materialsWSA Wheat straw ashXRD X-ray diffraction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors are very grateful to Laboratory Staff of NUSTInstitute of Civil Engineering National University of Sciencesand Technology Pakistan for their support in synthesis ofWSA and grinding of bentonite The first author would alsolike to acknowledge Higher Education Commission (HEC)Pakistan for providing the study grant

References

[1] V B Bosiljkov ldquoSCC mixes with poorly graded aggregate andhigh volume of limestone fillerrdquo Cement and Concrete Researchvol 33 no 9 pp 1279ndash1286 2003

[2] A Yahia M Tanimura and Y Shimoyama ldquoRheological prop-erties of highly flowable mortar containing limestone filler-effect of powder content and WC ratiordquo Cement and ConcreteResearch vol 35 no 3 pp 532ndash539 2005

[3] B Felekoglu K Tosun B Baradan A Altun and B UyulganldquoThe effect of fly ash and limestone fillers on the viscosityand compressive strength of self-compacting repair mortarsrdquoCement and Concrete Research vol 36 no 9 pp 1719ndash17262006

[4] A A A Hassan M Lachemi and K M A Hossain ldquoEffectof metakaolin and silica fume on the durability of self-consolidating concreterdquo Cement and Concrete Composites vol34 no 6 pp 801ndash807 2012

[5] KAMelo andAM PCarneiro ldquoEffect ofMetakaolinrsquos finessesand content in self-consolidating concreterdquo Construction andBuilding Materials vol 24 no 8 pp 1529ndash1535 2010

[6] M Safiuddin J S West and K A Soudki ldquoProperties offreshly mixed self-consolidating concretes incorporating ricehusk ash as a supplementary cementing materialrdquo Constructionand Building Materials vol 30 pp 833ndash842 2012

[7] T Akram S A Memon and H Obaid ldquoProduction of low costself compacting concrete using bagasse ashrdquo Construction andBuilding Materials vol 23 no 2 pp 703ndash712 2009

[8] S A Rizwan and T A Bier ldquoBlends of limestone powderand fly-ash enhance the response of self-compacting mortarsrdquoConstruction and Building Materials vol 27 no 1 pp 398ndash4032012

[9] J Mirza M Riaz A Naseer F Rehman A N Khan and QAli ldquoPakistani bentonite in mortars and concrete as low costconstruction materialrdquo Applied Clay Science vol 45 no 4 pp220ndash226 2009

[10] S A Memon R Arsalan S Khan and T Y Lo ldquoUtilizationof Pakistani bentonite as partial replacement of cement inconcreterdquo Construction and Building Materials vol 30 pp 237ndash242 2012

[11] H Biricik F Akoz I Berktay and A N Tulgar ldquoStudy ofpozzolanic properties of wheat straw ashrdquoCement and ConcreteResearch vol 29 no 5 pp 637ndash643 1999

[12] P Lawrence M Cyr and E Ringot ldquoMineral admixtures inmortarsrdquo Cement and Concrete Research vol 33 pp 1939ndash19472003

[13] Y Zhang A E Ghaly and B Li ldquoPhysical properties ofwheat straw varieties cultivated under different climatic and soilconditions in three continentsrdquoAmerican Journal of Engineeringand Applied Sciences vol 5 no 2 pp 98ndash106 2012

[14] USDA World Wheat Supply and Disappearance United StatesDepartment of Agriculture 2014 httpwwwersusdagovdata-productswheat-dataaspxU-OkUBEf38O


[15] X Pan and Y Sano ldquoFractionation of wheat straw by atmo-spheric acetic acid processrdquo Bioresource Technology vol 96 no11 pp 1256ndash1263 2005

[16] B Shrivastava P Nandal A Sharma et al ldquoSolid state biocon-version of wheat straw into digestible and nutritive ruminantfeed byGanoderma sp rckk02rdquo Bioresource Technology vol 107pp 347ndash351 2012

[17] S Hedjazi O Kordsachia R Patt A J Latibari and UTschirner ldquoAlkaline sulfite-anthraquinone (ASAQ) pulping ofwheat straw and totally chlorine free (TCF) bleaching of pulpsrdquoIndustrial Crops and Products vol 29 no 1 pp 27ndash36 2009

[18] H Chen F Wang C Zhang Y Shi G Jin and S YuanldquoPreparation of nano-silica materials the concept from wheatstrawrdquo Journal of Non-Crystalline Solids vol 356 no 50-51 pp2781ndash2785 2010

[19] F Talebnia D Karakashev and I Angelidaki ldquoProduction ofbioethanol from wheat straw an overview on pretreatmenthydrolysis and fermentationrdquo Bioresource Technology vol 101no 13 pp 4744ndash4753 2010

[20] L Xie M Liu B Ni X Zhang and Y Wang ldquoSlow-releasenitrogen and boron fertilizer from a functional superabsorbentformulation based on wheat straw and attapulgiterdquo ChemicalEngineering Journal vol 167 no 1 pp 342ndash348 2011

[21] T J Brown T Bide S D Hannis et al World MineralProduction 2004-08 British Geological Survey Keyworth UK2010

[22] T J Brown R A Shaw T Bide E Petavratzi E R Raycraftand A S Walters World Mineral Production 2007ndash11 BritishGeological Survey Keyworth UK 2013

[23] ASTM Annual Book of ASTM Standards Cement Lime Gyp-sum Standard Specification for Portland Cement C150-04ASTM International West Conshohocken Pa USA 2004

[24] P Chang and Y Peng ldquoInfluence of mixing techniques onproperties of high performance concreterdquoCement and ConcreteResearch vol 31 no 1 pp 87ndash95 2001

[25] S A Rizwan and T A Bier ldquoSelf-consolidating mortars usingvarious secondary raw materialsrdquo ACI Materials Journal vol106 no 1 pp 25ndash32 2009

[26] ASTM ldquoAnnual Book of ASTM Standards Cement Lime Gyp-sum Stand Test Method Flexural Strength Hydraul MortarsrdquoTech Rep C348-08 ASTM International New York NY USA2004

[27] ASTM ldquoAnnual Book of ASTM Standards Cement LimeGypsum Stand Test Method Compressive Strength HydraulMortarsrdquo Tech Rep C349-08 ASTM International USA 2004

[28] ASTM ldquoStandard test method density absorption voids hard-ened concreterdquo Annual Book of ASTM Standards Concrete andAggregates C 642-04 ASTM International 2004

[29] P Rawal Development of durable concrete from pulverized flyash and pozzolan derived from agricultural wastes [MS thesis]Asian Institute of Technology Bangkok Thailand 2003

[30] PHewlettLearsquos Chemistry of Cement andConcrete Elsevier SanDiego Calif USA 4th edition 1998

[31] P Metha and P Monteiro Concrete Microstructure Propertiesand Materials McGraw-Hill New York NY USA 2006

[32] ASTM Annual Book of ASTM Standards Concrete and Aggre-gates Standard Specification for Coal Fly Ash and Raw orCalcined Natural Pozzolan for Use in Concrete C618-08a ASTMInternational West Conshohocken Pa USA 2004

[33] H Biricik F Akoz F Turker and I Berktay ldquoResistanceto magnesium sulfate and sodium sulfate attack of mortars

containingwheat straw ashrdquoCement andConcrete Research vol30 no 8 pp 1189ndash1197 2000

[34] H Visvesvaraya ldquoRecycling of agricultural wastes with specialemphasis on rice husk ashrdquo in Proceedings of the Use of VegetablePlants and Their Fibers as Building Materials Joint Symposiumpp 1ndash22 RilemCIBNCCL Baghdad Iraq 1986

[35] S Ahmad S A Barbhuiya A Elahi and J Iqbal ldquoEffect ofPakistani bentonite on properties of mortar and concreterdquo ClayMinerals vol 46 no 1 pp 85ndash92 2011

[36] N M Al-Akhras and B A Abu-Alfoul ldquoEffect of wheat strawash on mechanical properties of autoclaved mortarrdquo Cementand Concrete Research vol 32 no 6 pp 859ndash863 2002

[37] F Lange H Mortel and V Rudert ldquoDense packing of cementpastes and resulting consequences on mortar propertiesrdquoCement and Concrete Research vol 27 no 10 pp 1481ndash14881997

[38] V Ramachandran Concrete Admixtures Handbook PropertiesScience and Technology Noyes Saddle River NJ USA 1995

[39] A M Neville ldquoAggregate bond and modulus of elasticity ofconcreterdquo ACI Materials Journal vol 94 no 1 pp 71ndash74 1997

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


on the response of self-compacting mortars (SCM) in freshand hardened states It was found that SCM using blendedraw materials improved the overall response than thoseusing either of them The durability of SCC prepared withmetakaolin and silica fume in replacement mode was investi-gated by Hassan et al [4] According to the test results highlydurable SCC mixtures were obtained using high metakaolincontent with an optimum replacement percentage of around20 Furthermore it was found out that the durability of SCCmixtures prepared with higher MK content was superior toSCC containing silica fume

Several researchers have evaluated the feasibility of usingwheat straw ash (WSA) and bentonite in normal concrete[9ndash11] However the data regarding utilization of WSA andbentonite in self-compacting paste (SCP) to the best ofour knowledge is scarce or nonexistent This research wastherefore carried out to evaluate the feasibility of WSAand bentonite self-compacting paste formulations The SCPformulations were prepared with 10 replacement level Thisreplacement level was chosen because a smaller amount ofsecondary raw material (SRM) results in optimum efficiencyand gives a large increase in strength while the use of largeamount has a smaller effect [12] The successful utilization inprevailing environment will offer multiple benefits includingcost effective solution to construction industry and reducedenvironmental and health issues and would have positiveimpact on the durability of the system

2 Wheat Straw and BentonitePotential-Global and Pakistan Statistics

Wheat is one of the primary sources of food for 245 billionpeople [13] In 2014 the annual global production of wheatwas around 705million tons out of which 75was producedby 18 countries while around 20 was produced by EU-27[14] According to the statistical data [14] Pakistan is rankedat 7 with 35 share to the world wheat production As perPan and Sano [15] the average yield of straw is around 13ndash14 kg per kg of grainThis places the global estimate of wheatstraw at around 534 million tons and for Pakistan this valueis around 1846million tonsThe current use of this abundantsupply of wheat straw as described by Zhang et al [13] is lim-ited to feeding stuff [16] pulp and paper [17] nanomaterials[18] bioethanol [19] fertilizer [20] and construction of mudhouses However in some parts of the world and especiallyin underdeveloped and developing countries wheat straw isburnt in open field causing environmental issues and healthproblems Huge amount of ash obtained after burning ofwheat straw probably has no use and getting rid of it is alsoa problem This research therefore evaluates the feasibility ofusing WSA in SCP formulations

As far as bentonite is concerned the total world produc-tion of bentonite has increased from 133 million tons in 2004[21] to 155 million tons in 2011 [22] while Pakistanrsquos annualproduction has increased from 6154 tons in 2004 [21] to30840 tons in 2011 [22] Moreover Pakistan has millions oftons of bentonite reserves [9] This research therefore alsoevaluates the feasibility of using bentonite (raw and heated)in SCP formulations

3 Experimental Investigation

31Materials andMix Proportion Locally availableOrdinaryPortland Cement (OPC) grade 425R in conformity withASTM C150 [23] was used Bentonite clay was collectedfrom Jehangira situated at 33∘5910158405610158401015840 latitude and 72∘1210158404710158401015840longitude according to Survey of Pakistan topographic sheet43 C1 [10] and it was studied in raw and heated conditionsHeat treatment was given at 150∘C [9] for 8 hrs and the claywas ground according to the procedure mentioned in [10]The powder was then sieved through number 200 standardmesh and resulting sample was used for SCP formulationsWSA was obtained by burning wheat straw available in 1ndash5 cm length The burning of wheat straw was carried outfor 5 hrs in a temperature controlled electric furnace havingsmoke vent at the top During the entire burning processtemperature was maintained at 670∘C as reported to bequite effective to attain good pozzolanic properties [11]For all SCP formulations bentonite and WSA were usedin replacement mode by 10 weight of cement A thirdgeneration polycarboxylate ester based powder type super-plasticizer Melflux 2651 was used to achieve flow level of 30 plusmn1 cm as measured by Hagermanrsquos mini slump The followingspecimen designations were used for SCP formulations

CEM represents reference SCP formulationC + 10 WSA represents SCP formulation with 10wheat straw ashC + 10BN (H) represents SCP formulationwith 10heated bentoniteC + 10 BN(R) represents SCP formulation with 10raw bentonite

32 Mixing Regime Hobart Mixer (5 L capacity) was usedfor mixing SCP formulations Various mixing regimes [24]arementioned in the literature however after experimentingthe following was adopted The constituents were manuallymixed in dry state for 1-2minutes followed by feeding into thebowl the dry mixture along with the requisite mixing waterpredicted by water demand test A slowmixing (145 rpm) wasdone for 60 seconds followed by fast mixing (285 rpm) for120 seconds [25] The total mixing time was 3 minutes (180seconds) for all SCP formulations

33 Testing of Specimens The particle size surface areaand surface morphology of powdered WSA and bentonitesamples were determined by using Laser Granulometer(Coulter LS 230) Brunauer-Emmett-Teller (Finesorb-3010)and Environmental Scanning Electron Microscope (XL 30ESEM FEG) For chemical composition X-ray fluorescence(JSX-3100RII) technique was used The physical propertiesand chemical composition results of powdered samples arerepresentative of three samples

The water demand and setting times of reference SCP aswell as those containing 10 SRM (in replacement mode)were determined by Vicat apparatus at 20 plusmn 1∘C and 20 plusmn 5relative humidity The superplasticizer amount required fora target flow of 30 plusmn 1 cm was obtained for all formulations









2O





















Agglomerates

5120583m

(a)

1120583m

(b)


5120583m

(c)

1120583m

(d)

5120583m

(e)

Surface pits

1120583m

(f)









0 10 20 30 40 50 60 70

Inte

nsity




QC

CQ K

Cl QMI

Q

QM

I

QCl

Cl I Cl MQ

Q

IM Q Q

2120579 (deg)





synmonocline


0

05

1

15

2

25

3

35

4

T25 Funnel time

Tim

e (s)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)



0

10

20

30

40

50

60

70

80


Com

pres

sive s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(a)

0

5

10

15

20

25


Flex

ure s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(b)


2

21

22

23

24

25

26

27

28

29

Formulations

Wat

er ab

sorp

tion

()

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)






0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)


SO4


0

5

10

15

20

25

30


C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4












1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials











2O





















Agglomerates

5120583m

(a)

1120583m

(b)


5120583m

(c)

1120583m

(d)

5120583m

(e)

Surface pits

1120583m

(f)









0 10 20 30 40 50 60 70

Inte

nsity




QC

CQ K

Cl QMI

Q

QM

I

QCl

Cl I Cl MQ

Q

IM Q Q

2120579 (deg)





synmonocline


0

05

1

15

2

25

3

35

4

T25 Funnel time

Tim

e (s)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)



0

10

20

30

40

50

60

70

80


Com

pres

sive s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(a)

0

5

10

15

20

25


Flex

ure s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(b)


2

21

22

23

24

25

26

27

28

29

Formulations

Wat

er ab

sorp

tion

()

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)






0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)


SO4


0

5

10

15

20

25

30


C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4












1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials















Agglomerates

5120583m

(a)

1120583m

(b)


5120583m

(c)

1120583m

(d)

5120583m

(e)

Surface pits

1120583m

(f)









0 10 20 30 40 50 60 70

Inte

nsity




QC

CQ K

Cl QMI

Q

QM

I

QCl

Cl I Cl MQ

Q

IM Q Q

2120579 (deg)





synmonocline


0

05

1

15

2

25

3

35

4

T25 Funnel time

Tim

e (s)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)



0

10

20

30

40

50

60

70

80


Com

pres

sive s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(a)

0

5

10

15

20

25


Flex

ure s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(b)


2

21

22

23

24

25

26

27

28

29

Formulations

Wat

er ab

sorp

tion

()

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)






0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)


SO4


0

5

10

15

20

25

30


C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4












1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 10 20 30 40 50 60 70

Inte

nsity




QC

CQ K

Cl QMI

Q

QM

I

QCl

Cl I Cl MQ

Q

IM Q Q

2120579 (deg)





synmonocline


0

05

1

15

2

25

3

35

4

T25 Funnel time

Tim

e (s)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)



0

10

20

30

40

50

60

70

80


Com

pres

sive s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(a)

0

5

10

15

20

25


Flex

ure s

treng

th (M

Pa)

CEM

C+10

WSA

C+10

BN(H

)C+10

BN(R

)

(b)


2

21

22

23

24

25

26

27

28

29

Formulations

Wat

er ab

sorp

tion

()

CEM

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)






0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)


SO4


0

5

10

15

20

25

30


C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4












1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

05

1

15

2

25

3

14 days 28 days

Wei

ght l

oss (

HCl

expo

sure

) (

)

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEM

(a)

005

115

225

335

445

5

14 days 28 days

C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

2SO

4ex

posu

re) (

)

Wei

ght l

oss (

H

CEM

(b)


SO4


0

5

10

15

20

25

30


C+10

WSA

C+10

BN(H

)

C+10

BN(R

)

CEMStre

ngth

loss

(HCl

expo

sure

) (

)

(a)

0

5

10

15

20

25

30

35

40

45


Wei

ght l

oss (

H2S

O4

expo

sure

) (

)

C+10

WSA

C+10

BN(R

)

CEM

C+10

BN(H

)

(b)


SO4












1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




1 day

Energy (keV)

Intensity Si

SAl

Ca

K

O

MgC Fe

5120583mtimes5000

(a)

Ettringite

Portlandite

7 days

Energy (keV)

Intensity

SiSAl

Ca

K

O

Mg Fe

20120583mtimes1000

CndashSndashH

(b)

Energy (keV)

Intensity

Si

SAl

Ca

KOFe

1 day

WSA particle

5120583m

MgC

times5000

(c)

Ettringite


Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

7 days

Mg

times1000

CndashSndashH

(d)

Energy (keV)

Intensity Si

SAl

Ca

K

O

Fe

1 day

MgNa

5120583m times5000

(e)

Energy (keV)

Intensity

SiSAl

K

O

FeEttringite

Bentonite (H)

7 days

20120583m

MgNa

Ca

times1000

CndashSndashH

(f)

Energy (keV)

Intensity

Si

SAl

Ca

K

O

Fe

1 day

MgC

5120583mtimes5000

(g)

Energy (keV)

Intensity

Si

SAl Ca

K

O

FeC

Ettringite


7 days

5120583m

Mg

times3000

(h)






0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

P + L

P + L

H + LH + L

H + L

H + L

H + L

H + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-1 day

CEM-1 day

C + 10 BN(H)-1 day

C + 10 WSA-1 day



(a)

0 10 20 30 40 50 60 70

Inte

nsity

E

E

E

E

P

PP

P

P

P

P

P

P + L

P + L

H + LH + L

H + LH + L

P + L

H + LH + L

P + L

H + LH + L

2120579 (deg)

C + 10 BN(R)-7 days

CEM-7 days

C + 10 BN(H)-7 days

C + 10 WSA-7 days



(b)











2O)] hatrurite [Ca

3SiO5] and











Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










Abbreviations




Acknowledgments


References

















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article experimental investigation on use of

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