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Research ArticleThe Sulphate Effect on Lijiaxia Concrete Dam (China) Gallery

Xufen Zhu1 Ji Li2 Yi Zhang2 Hanzhou Song1 and Hu Zheng1

1School of Earth Science and Engineering Hohai University Nanjing 210098 China2Yellow River Upstream Hydropower Limited Liability Company Xining 810008 China

Correspondence should be addressed to Hu Zheng zhenghuhhueducn

Received 27 April 2017 Accepted 3 August 2017 Published 3 October 2017

Academic Editor Petros Gikas

Copyright copy 2017 Xufen Zhu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The concrete degradation is one of the most serious problems for a dam construct during the normal operation which determinesthe dam service lifeHence it is very important to reduce the extent of the damconcrete degradation for the safety of the damnormaloperation Here Lijiaxia hydroelectric station is taken as an example and a comprehensive method to assess the sulphate effect ondam gallery is proposed Eleven samples in total were taken from three difference locations by the drill bore The microstructuralinvestigations including X-ray fluorescence spectrometry (XRF) X-ray diffraction (XRD) scanning electron microscope (SEM)and energy dispersive spectroscopy (EDS) were conducted to assess the sulphate attack and the degradation degree Meanwhilethe water chemical analysis was applied to reveal the mechanism of concrete degradation The experimental and analysis resultsindicate that the concrete degradation degree varies with the location of the samples The components of the concrete change andthe content of SO

3increase dramatically during degradation Moreover the mineral facies of the concrete change correspondingly

with the cement paste substituted by the calcite calcium vitriol and gypsum The reinforcement and precaution measures aresuggested based on the results of the degradation assessment

1 Introduction

Lots of hydropower stations were constructed along theYangtze River and Yellow River in China from 1950s espe-cially in the southwestern China [1ndash3] Meanwhile the con-crete dams have to be built on the rivers with the hydropowerstations Most of the concrete dams have been workingfor decades and the concrete degradation would happenwith time [4] Concrete degradation is mainly attached byreactive liquids and gases which could cause the chemicalcolloidal or physicochemical deterioration and disintegra-tion of solid concrete components and structures [5] Thedegradation process would lead to the concrete weight lossand surface spalling [6 7] There are several different reasonscausing concrete degradation including salt water or acidicground water microbes in sewer pipes sulphates chloridesnitrates fluorides sulphides and industrial waste like slagand corrosive gases and so on [5 8] The combination ofthe factors mentioned above leads to concrete degradationwhile the concrete structures are exposed to an aggressiveenvironment Sulphates effect is one of the most ubiquitousones in the natural environment but the mechanism of

sulphate attack on cement concrete is not well understood[9] This has limited the confidence to the assessment ofdegradation degree which is the main factor of the damstability Hence a systematic research effort on sulphate effectis necessary to the safety of dam construction and the normaloperation of the hydropower station

The sulphate concrete degradation inspection and eval-uation have attracted much scientific attention in recentyears [10 11] (Hu et al 2016) Many different methods forthe concrete degradation assessment were proposed [12 13]For example a borehole could be drilled in the concretedam and the core would be taken out to check the concretedegradation degree The drilled core method is one of themost common methods because the inside of the concretecould be revealed and exposed directly by this methodMoreover the concrete core could be used as the samples oflaboratory tests [14] Some other methods including inden-tation method rebound method and ultrasonic method arealso applied to the dam concrete degradation examination[15] However almost all of the methods mentioned abovecould only provide themacroscopically evaluation results andqualitatively describe the degradation phenomena of the dam

HindawiJournal of ChemistryVolume 2017 Article ID 8698759 8 pageshttpsdoiorg10115520178698759

2 Journal of Chemistry

(a) (b)Qinghai Province

XiningHaidong

Location of the project


e Yellow River

e Yellow River

Villages

Figure 1 Map showing location of the project Lijiaxia hydropower station (satellite image from Google Earth)

concreteThe substantial mechanism of concrete degradationcould not be understood because the precipitations after thedegradation are varying

Recently several researchers have studied the concretedamdegradation based on themicrostructural investigationssuch as XRF XRD SEM and EDS [16 17] Romer andLienemann [18] presented the deterioration of shotcrete inthe safety gallery by the salt-containing water based on theXRF and XRD microstructural measurements Hu et al [19]have shown that the concrete of Yongan Dam is deteriorateddue to the thaumasite form of sulphate attack according tomicroanalytical investigations SEM and energy disperse X-ray (EDX) Portella et al [14] analyzed the elemental chemicalcomposition and phases of a concrete dam with over 50 yearsof operation by EDS and XRD techniques However most ofthe microanalytical studies on the dam concrete degradationare based on single or two experimental techniques whichmight cause the local uncertainty of the precipitations

In this paper both in situ investigations and a series oflaboratory tests including XRF XRD SEM and EDS wereconducted to analyze the sulphate attach degradation ofLijiaxia hydroelectric station dam gallery concrete Compre-hensive concrete degradation analysis was done based onthe field investigations and laboratory tests results At theend the precaution measures were suggested to control thedam gallery concrete degradation The research results couldprovide useful information for future inspections for Lijiaxiahydroelectric station dam and regular inspections for othersimilar concrete dams

2 Study Areas

Lijiaxia hydropower station is located in Jainca CountyQinghai Province China which is the third step hydropowerstation of upper reaches of the Yellow River (Figure 1) Thedam is a concrete arch-gravity dam with length 41439m andheight 515m The dam houses a hydroelectric power stationwith 5 times 400MW generators for a total installed capacityof 2000MW The hydropower station is the second largesthydropower station in the northwestern of China which isthe pivotal role for the electricity generating and irrigation inthis area Moreover there are many people living in villagesat the downstream of the dam Hence the stability of theriver dam is very important to the normal operations of the

hydropower station and the safety of the people living atdownstream

The schematic of the hydropower station dam galleryand the location details of sampling are shown in Figure 2The field investigation shows that the worst location ofdegradation is BH3 (elevation 2038) the degradation degreeof the surface concrete is dramatic Lots of local apophysisand desquamate phenomena could be seen on the concretestep at the BH3 position Conversely the degradation degreesof the surface concrete around the BH1 and BH2 are notthat terrible Only several local apophysis and desquamatephenomena could be found on the step (Figure 2)Three con-crete samples beside the three boreholes and eight concretesamples from different depths of borehole cores were takenThe depth details of each borehole core sample are shown inTable 1 In order to clarify the mechanism of this dam galleryconcrete degradation several laboratory tests including XRFXRD SEM and EDS were conducted to inspect the concretedegradation and degradation degree of the concrete for bothborehole and gallery surface samples

3 Chemical Constituents Detecting ofDegradation Concrete

31 XRF Experiments and Results The XRF tests were con-ducted on all samples from three locations to investigatethe basic chemical composition X-ray fluorescence (XRF)is the emission of fluorescent X-rays from a material thathas been excited by bombarding with high-energy X-rays orgamma rays The phenomenon is widely used for buildingmaterials and for research in geochemistry forensic scienceand archaeology [20 21] Both of the major constituents andtrace components can be detected by the XRF test Accordingto the XRF test results the chemical constituents and loss onignitions (LOI) of the concrete samples are shown in Tables 2and 3 respectively

The chemical compositions of all 8 concrete samples arevery closeThe basic elements are Si Al Ca and Fe (Table 2)The site survey results also indicate that all of these samplesare fairly intact (Figure 2) The average LOI value is 1124and average mass fraction percentage of SiO

2is 45 and that

of SO3is only 091The LOI values of the samples have very

good positive correlationwith themass fraction percentage ofCaO (Figure 3) which indicates that the LOI of the concrete is

Journal of Chemistry 3

Vertical drillInclined holeGallery surface concrete

Borehole concretePresinian migmatite

6m0

BH1

BH2

BH3

Figure 2 The details of the sampling locations and the concrete corrosion photos

Table 1 The number and depth of the samples

Number of borehole Number of samples Depth of the sample position

BH1

BH1-0 0BH1-1 045mBH1-2 130mBH1-3 325mBH1-4 435m

BH2BH2-0 0BH2-1 040mBH2-2 570m

BH3BH3-0 0BH3-1 060mBH3-2 690m

mainly caused by CaO decomposing and the organic contentis very small

Three concrete samples from the dam gallery surfacewhich are in serious degradation according to the site survey(Figure 2) were also taken to do the XRF test The averageLOI value is 2176 which means there are lots of materialslost at 1000ndash1100∘C heat for the degradation concrete of thedam gallery surfaceThe averagemass fraction percentages ofSiO2are only 1743which is less than half of that of borehole

samples Nevertheless the average mass fraction percentageof SO

3reaches 3338

The comparison of chemical constituents and LOIbetween surface and borehole concrete samples is shown inFigure 3 The main differences between seriously corrodedconcrete taken from the gallery surface and fairly intactconcrete are the SiO

2 CaO Al

2O3 and SO

3contents For

the fairly intact concrete the contents of SiO2and Al

2O3

are more than those of degradation concrete Conversely thecontents of CaO and SO

3of fairly intact concrete are less

than those of degradation concrete All the above test resultsindicate that the concrete degradation at Lijiaxia dam galleryconcrete belongs to sulphate attack In order to analyze


Table 2 The basic element compositions of the concrete samples from boreholes

Number LOI Chemical compositions ()SiO2

Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl

BH1-1 1280 4266 1106 2272 422 142 107 113 210 045 007 002BH1-2 1117 4434 1228 1929 482 219 072 124 305 051 008 002BH1-3 1134 4286 1156 2120 520 181 089 141 281 052 009 002BH1-4 554 5392 1316 1106 637 339 047 157 336 075 011 002BH2-1 1702 3469 745 3143 319 113 172 086 176 031 005 014BH2-2 1226 4333 1170 2142 390 218 115 138 191 041 006 004BH3-1 973 5025 1393 1330 501 214 054 166 247 057 009 001BH3-2 1006 4794 1278 1591 468 194 069 151 358 050 009 003Average 1124 4500 1174 1954 467 203 091 135 263 050 008 004

Table 3 The basic element compositions of the concrete samples from gallery surface


Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl

BH1-0 2417 1910 437 3292 300 041 1082 039 417 025 005 009BH2-0 2034 1754 338 3327 250 036 2007 035 155 019 004 021BH3-0 2076 1565 315 3394 231 037 2220 023 092 015 004 012Average 2176 1743 363 3338 260 038 1770 032 221 020 004 014

LOI

SiO

2

Al2

O3

CaO

Fe2O

3

K2O

SO3

Na2

O

MgO

TiO

2

MnO Cl

Chemical constituentsBorehole concreteGallery surface concrete

0

10

20

30

40

50

Perc

ent m

ass b

y w

eigh

t (

)

Figure 3The comparison XRF tests results between gallery surfaceand borehole concrete specimens

the degradation products of the concrete XRD tests wereconducted to investigate the main mineral facies of all theconcrete samples

32 The Main Mineral Facies Analysis by XRD XRD is aneffective tool for identifying the atomic and molecular struc-tures of a crystal The crystalline atoms can cause a beam ofincident X-rays to diffract into many specific directions Thecrystallographer can produce a three-dimensional picture ofthe density of electrons within the crystal according to theangles and intensities of these diffracted beams Hence themean positions of the atoms in the crystal chemical bondsand disorder can be determined [22ndash24] All of the 11 sampleswere subjected to XRD tests to investigate the elements fabricexisting state and the mineral facies [18 19]

Similar XRD tests results of the borehole samples wereobtained from the three difference locations (Figure 4)However the gallery surface samples vary with the boreholesamples even though they are from the same location Themain reason might be that the degradation degrees aredifferent which also could be found by the site survey andXRF test results The SiO

2and CaCO

3are the main matters

of the samples including surface and borehole sampleswhere the SiO

2is from the concrete aggregate while CaCO

3

indicates that the carbonization happened in the concreteThe main difference between the borehole concrete andgallery surface is the set cement which is composed ofthe hydrated cement products such as Ca(OH)

2 The set

cement could not be found in the seriously corroded gallerysurface samples by the XRD test but was found in theborehole samples The difference confirms that samples fromgallery surface have been eroded in the corrosive mediumenvironment Moreover the CaSO

4sdot05H2Owere detected in

the samples from BH2-0 and BH3-0 locations which is thetypical mineral of the concrete degradation by the sulphatesolution [17 25] The CaSO

4sdot05H2O mineral shows that the

concrete degradations from BH2-0 and BH3-0 are the mostsevere locations among all 11 samples

Another interesting thing found from the XRD spectraresult is that the ettringite might exist in BH1-3 and BH1-4samples (2120579 = 875 d = 997sim1011) (Figure 4) In order tomake it clear whether the ettringite exists as the degradationproducts SEM and EDS tests were conducted on BH1-3 andBH1-4 samples

33 The SEM and EDS Tests Both SEM and EDS testswere conducted in the Center of Modern Analysis NanjingUniversity ChinaThe SEM tests were conducted by aHitachi


2 (∘)

S4middot05（2

BH1-0

BH2-0

BH3-0

605040302010

３Ｃ2

3

(a)

BH1-1

BH1-2

BH1-3

BH1-4

2 (∘)605040302010

３Ｃ2

3

Ca (（)2

(b)

３Ｃ2

3

BH2-1

BH2-2

BH3-1

BH3-2

2 (∘)605040302010

Ca (（)2

(c)

Figure 4 The XRD spectrum results (a) the gallery surface (b) samples from BH1 (c) samples from BH2 and BH3

S-3400N II scanning electron microscope and the SEMimages of BH1-3 and BH1-4 samples are shown in Figure 5The relative concentration rod-like crystalline contents couldbe seen in both of two samples which is very similar tothe crystal shape of ettringite (3CaOsdotAl

2O3sdot3CaSO

4sdot32H2O)

[17]Meanwhile the EDS spectra results are shown in Fig-

ure 6 which indicate that the major elements of the rod-like crystalline contents and the adjacent mineral are CaS and Al The corresponding oxides of Ca S and Al areCaO SO

3 and Al

2O3 and the total mass contents of these

oxides are 9186 and 9580 for BH1-3 and BH1-4 samplesrespectively Moreover Ca S and Al are the basic elementsof ettringite and the total contents of the correspondingoxides are over 90 Hence it is confirmed that the ettringitemineral is generated in the BH1 [17 25 26] which is thetypical sulphate attack product Hence proper precautionshave to be taken on this hydropower station dam galleryespecially for the sulphate attack prevention

4 The Mechanism of Concrete Degradation

The above tests results indicate that the dam gallery con-crete of the Lijiaxia hydropower station dam was subjectedto degradation damage to some extent especially by thesulphate attack not only for the surface concrete In orderto investigate the mechanism of the concrete degradationthe water samples were collected from the three differentboreholes The water quality tests were operated for eachof the samples and the results are shown in Table 4 Thecontents of SO

4

2minus are more than 1000mgL in the water fromthree boreholes which could corrode the ordinary Portlandcement but not sulphate resistant one However the contentof SO4

2minus ismore than 3000mgL in BH2 which indicates thateven sulphate resistant cement could get degradation

There are not onlyCa2+ and SO4

2minus existing in the concretegroundwater but also some other ions However the otherions would affect the position of the critical saturation pointdue to the ion effect The saturation indexes (SI) between


(a) (b)

Figure 5 The SEM images of the concrete samples from BH1 BH1-3 (a) and BH1-4 (b) sample

Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)

Figure 6 The EDS spectra of the concrete samples from BH1 (a) BH1-3 sample (b) BH1-4 sample

carbonates [15] sulphates and the groundwater from thesethree boreholes were analyzed (Table 5) The analyzed resultsshow that SI gt 0 between sulphates and the groundwaterfromBH2 andBH3whichmeans themineral is precipitatingwhile SI lt 0 for BH1 which means the mineral is dissolvedSI gt 0 between carbonates and the groundwater of all threeboreholes which means the concrete is being corroded andthemineral is precipitating All of the concrete from the three

locations could get degradation and some new substancemight be generated in the view of the chemical thermo-dynamics In sulphate environment the SO

4

2minus would havechemical reaction with Ca(OH)

2in concrete to form CaSO

4

firstly and then CaSO4would have chemical reaction with

hydrated calcium aluminate ormonosulfate to form ettringite(3CaOsdotAl

2O3sdot3CaSO

4sdot32H2O) The reaction formulas are

shown in the following

4CaOsdotAl2O3sdot19H2O + 2Ca (OH)2 + 3SO4

2minus + 14H2O 997888rarr 3CaOsdotAl

2O3sdot3CaSO

4sdot32H2O + 6OHminus

3CaOsdotAl2O3CaSO

4sdot18H2O + 2Ca (OH)2 + 2SO4


2O3sdot3CaSO


(1)

However Ca(OH)2and CaSO

4in the concrete could form

gypsum with a high concentration of SO4

2minus

Ca (OH)2 + SO42minus + 2H

2O 997888rarr CaSO

42H2O + 2OHminus

3CaOsdot2SiO2sdot3H2O + 3SO

4

2minus + 8H2O 997888rarr 3 (CaSO

4sdot2H2O) + 6OHminus + 2SiO

2sdotH2O

(2)

Both the microstructural investigation results and waterquality analysis show that the Lijiaxia concrete dam gallery

is subjected to concrete degradation especially by sulphateattack The proper reinforcement and precaution measures


Table 4 The statistic results of the hydrochemical characteristics from three boreholes

Locations SO4

2minus (mgL) HCO3

minus (mmolL) pH TDS (mgL) Hardness (meqL) CategoriesBH1 125300 002 1150 272334 1873 SO

4sdotCl-CasdotNa

BH2 322500 008 935 603175 5183 SO4sdotCl-CasdotNa


Table 5 The saturation index (SI) of the groundwater from the three boreholes

Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4

BH1 160 minus027 141 minus930 minus854 minus770 minus886BH2 113 025 105 minus655 minus580 minus659 minus842BH3 169 004 163 minus694 minus618 minus736 minus872

have to be conducted to limit further degradation and makesure the safety of dam construction Firstly the dam gallerysurface concrete is corroded seriously which has to bereinforced According to the water quality analysis resultsthe sulphate resistant concrete is suggested to be used in thereinforcement In addition the drainage holes in the galleryare suggested to be checked over to clarify whether they areeffectively plugged or notThe plugged drainage holes have tobe cleared to restore thewater drainage function which coulddecrease the alternate dry and wet of the gallery concrete

5 Conclusions

The degradation of the concrete dam is one of the mostimportant issues after the hydropower station is built Areasonable and correct method is the key role of the concretedegradation evaluation In this paper the comprehensiveevaluation method by using XRF XRD SEM and EDSis applied on the gallery concrete of Lijiaxia hydropowerstation In this paper the experimental method of damconcrete degradation assessment could be a useful referencefor future inspections for Lijiaxia hydroelectric station damand regular inspections for other similar concrete dams Ourexperimental study has made the following findings

(1) Both of the gallery surface and borehole concrete arecorroded The degradation degree of gallery surface concreteis much more severe than the borehole concrete But thedegradation is not enough to cause harm to the hydropowerstation The surface concrete is suggested to be reinforced bythe sulphate resistant concrete based on experimental results

(2) The main chemical composition contents of theconcrete change during the degradation and the SO

3content

increases obviously as the degradation degree increasesMoreover the mineral facies of the concrete change corre-spondingly and the set cement would be replaced by calciteand ettringite which indicates that the concrete is subjectedto the sulphate attack

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

This work was supported by the National Natural ScienceFoundation of China (Grant no 41272265) the NSF (JiangsuChina) (Grant no BK20140845) the China PostdoctoralScience Foundation (Grant no 2014M561567) and the Fun-damental Research Funds for the Central Universities ofChina (Grant no 2014B03414)

References

[1] F T Zhang Y J Duan S M Cao J W Wang and D QTan ldquoHigh genetic diversity in population of Lepturichthysfimbriata from the Yangtze River revealed by microsatelliteDNA analysisrdquo Chinese Science Bulletin vol 57 no 5 pp 487ndash491 2012

[2] L Zhang D X Yang Y W Liu Y T Che and D J QinldquoImpact of impoundment on groundwater seepage in theThreeGorges Dam in China based on CFCs and stable isotopesrdquoEnvironmental Earth Sciences vol 72 no 11 pp 4491ndash50002014

[3] B-R Chen Q-P Li X-T Feng Y-X Xiao G-L Feng and L-X Hu ldquoMicroseismic monitoring of columnar jointed basaltfracture activity a trial at the Baihetan Hydropower StationChinardquo Journal of Seismology vol 18 no 4 pp 773ndash793 2014

[4] J Li X Liang X Mao and H Peng ldquoGeochemical analysis oneducts in the drainage corridor of a big damover Yangtze RiverrdquoJournal of Earth Science vol 23 no 2 pp 180ndash186 2012

[5] I Biczok and N Blasovszky ldquoConcrete corrosion and concreteprotectionrdquo Chemical Publishing Company 1964 New York

[6] K A T Vu andM G Stewart ldquoStructural reliability of concretebridges including improved chloride-induced corrosion mod-elsrdquo Structural Safety vol 22 no 4 pp 313ndash333 2000

[7] G Dhinakaran S Thilgavathi and J Venkataramana ldquoCom-pressive strength and chloride resistance of metakaolin con-creterdquoKSCE Journal of Civil Engineering vol 16 no 7 pp 1209ndash1217 2012

[8] R Tichy P Lens J T C Grotenhuis and P Bos ldquoSolid-statereduced sulfur compounds Environmental aspects and bio-remediationrdquo Critical Reviews in Environmental Science andTechnology vol 28 no 1 pp 1ndash40 1998

[9] P Richard andMH Cheyrezy ldquoReactive powder concretes withhigh ductility and 200-800 MPa compressive strengthrdquo ACISpecial Publication vol 144 pp 10ndash14359 1994


[10] O Poupard V LrsquoHostis S Catinaud and I Petre-Lazar ldquoCor-rosion damage diagnosis of a reinforced concrete beam after40 years natural exposure in marine environmentrdquo Cement andConcrete Research vol 36 no 3 pp 504ndash520 2006

[11] BMa X Gao E A Byars andQ Zhou ldquoThaumasite formationin a tunnel of Bapanxia Dam in Western Chinardquo Cement andConcrete Research vol 36 no 4 pp 716ndash722 2006

[12] S-S Kim and S-T Lee ldquoMicrostructural observations on thedeterioration of concrete structure for sewage water treatmentrdquoKSCE Journal of Civil Engineering vol 14 no 5 pp 753ndash7582010

[13] Z Liu G De Schutter D Deng and Z Yu ldquoMicro-analysis ofthe role of interfacial transition zone in ldquosalt weatheringrdquo onconcreterdquo Construction and Building Materials vol 24 no 11pp 2052ndash2059 2010

[14] K F Portella A Joukoski V Swinka Filho M A Soares andE S Ferreira ldquoPhysical chemistry research of a concrete damwith over 50 years of operationrdquo Ceramica vol 58 no 347 pp374ndash380 2012

[15] H Z SongEnvironmental hydrogeology around dam-site ChinaWaterPower Press Beijing China 2007

[16] F Goetz-Neunhoeffer J Neubauer and P Schwesig ldquoMiner-alogical characteristics of ettringites synthesized from solutionsand suspensionsrdquo Cement and Concrete Research vol 36 no 1pp 65ndash70 2006

[17] W-Y Ouyang J-K Chen and M-Q Jiang ldquoEvolution ofsurface hardness of concrete under sulfate attackrdquo Constructionand Building Materials vol 53 pp 419ndash424 2014

[18] M Romer and P Lienemann ldquoDeterioration of shotcrete inthe safety gallery of the gotthard motorway tunnel by salt-containing waterrdquo Chimia vol 52 no 5 pp 197ndash201 1998

[19] M Y Hu F M Long and M S Tang ldquoThe thaumasite form ofsulfate attack in concrete of YonganDamrdquoCement and ConcreteResearch vol 36 no 10 2006

[20] E P Bertin Principles and Practice of X-Ray SpectrometricAnalysis Kluwer AcademicPlenum Publishers Boston MassUSA 1979

[21] B Beckhoff h B Kanngieszliger N Langhoff R Wedell andH Wolff Handbook of Practical X-Ray Fluorescence AnalysisSpringer Berlin Heidelberg Berlin Heidelberg 2007

[22] W H Bragg andW L Bragg ldquoThe structure of the diamondrdquo inProceedings of the Royal Society of London Series A ContainingPapers of a Mathematical and Physical Character vol 91 p 557London UK 1913

[23] W L Bragg R James and C Bosanquet ldquoThe distribution ofelectrons around the nucleus in the sodiumand chlorine atomsrdquoPhilosophical Magazine vol 44 no 261 pp 433ndash449 1922

[24] B Rupp and JWang ldquoPredictive models for protein crystalliza-tionrdquoMethods vol 34 no 3 pp 390ndash407 2004

[25] J-K Chen and M-Q Jiang ldquoLong-term evolution of delayedettringite and gypsum inPortland cementmortars under sulfateerosionrdquo Construction and Building Materials vol 23 no 2 pp812ndash816 2009

[26] B G Ma ldquoSulfate resistance mechanism of high-performanceconcrete containingNCIrdquo JournalWuhanUniversity of Technol-ogy vol 4 no 1 pp 6ndash15 1999

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(a) (b)Qinghai Province

XiningHaidong



e Yellow River

e Yellow River

Villages

Figure 1 Map showing location of the project Lijiaxia hydropower station (satellite image from Google Earth)

concreteThe substantial mechanism of concrete degradationcould not be understood because the precipitations after thedegradation are varying

Recently several researchers have studied the concretedamdegradation based on themicrostructural investigationssuch as XRF XRD SEM and EDS [16 17] Romer andLienemann [18] presented the deterioration of shotcrete inthe safety gallery by the salt-containing water based on theXRF and XRD microstructural measurements Hu et al [19]have shown that the concrete of Yongan Dam is deteriorateddue to the thaumasite form of sulphate attack according tomicroanalytical investigations SEM and energy disperse X-ray (EDX) Portella et al [14] analyzed the elemental chemicalcomposition and phases of a concrete dam with over 50 yearsof operation by EDS and XRD techniques However most ofthe microanalytical studies on the dam concrete degradationare based on single or two experimental techniques whichmight cause the local uncertainty of the precipitations

In this paper both in situ investigations and a series oflaboratory tests including XRF XRD SEM and EDS wereconducted to analyze the sulphate attach degradation ofLijiaxia hydroelectric station dam gallery concrete Compre-hensive concrete degradation analysis was done based onthe field investigations and laboratory tests results At theend the precaution measures were suggested to control thedam gallery concrete degradation The research results couldprovide useful information for future inspections for Lijiaxiahydroelectric station dam and regular inspections for othersimilar concrete dams

2 Study Areas

Lijiaxia hydropower station is located in Jainca CountyQinghai Province China which is the third step hydropowerstation of upper reaches of the Yellow River (Figure 1) Thedam is a concrete arch-gravity dam with length 41439m andheight 515m The dam houses a hydroelectric power stationwith 5 times 400MW generators for a total installed capacityof 2000MW The hydropower station is the second largesthydropower station in the northwestern of China which isthe pivotal role for the electricity generating and irrigation inthis area Moreover there are many people living in villagesat the downstream of the dam Hence the stability of theriver dam is very important to the normal operations of the

hydropower station and the safety of the people living atdownstream

The schematic of the hydropower station dam galleryand the location details of sampling are shown in Figure 2The field investigation shows that the worst location ofdegradation is BH3 (elevation 2038) the degradation degreeof the surface concrete is dramatic Lots of local apophysisand desquamate phenomena could be seen on the concretestep at the BH3 position Conversely the degradation degreesof the surface concrete around the BH1 and BH2 are notthat terrible Only several local apophysis and desquamatephenomena could be found on the step (Figure 2)Three con-crete samples beside the three boreholes and eight concretesamples from different depths of borehole cores were takenThe depth details of each borehole core sample are shown inTable 1 In order to clarify the mechanism of this dam galleryconcrete degradation several laboratory tests including XRFXRD SEM and EDS were conducted to inspect the concretedegradation and degradation degree of the concrete for bothborehole and gallery surface samples

3 Chemical Constituents Detecting ofDegradation Concrete

31 XRF Experiments and Results The XRF tests were con-ducted on all samples from three locations to investigatethe basic chemical composition X-ray fluorescence (XRF)is the emission of fluorescent X-rays from a material thathas been excited by bombarding with high-energy X-rays orgamma rays The phenomenon is widely used for buildingmaterials and for research in geochemistry forensic scienceand archaeology [20 21] Both of the major constituents andtrace components can be detected by the XRF test Accordingto the XRF test results the chemical constituents and loss onignitions (LOI) of the concrete samples are shown in Tables 2and 3 respectively

The chemical compositions of all 8 concrete samples arevery closeThe basic elements are Si Al Ca and Fe (Table 2)The site survey results also indicate that all of these samplesare fairly intact (Figure 2) The average LOI value is 1124and average mass fraction percentage of SiO

2is 45 and that

of SO3is only 091The LOI values of the samples have very

good positive correlationwith themass fraction percentage ofCaO (Figure 3) which indicates that the LOI of the concrete is




6m0

BH1

BH2

BH3




BH1

BH1-0 0BH1-1 045mBH1-2 130mBH1-3 325mBH1-4 435m

BH2BH2-0 0BH2-1 040mBH2-2 570m

BH3BH3-0 0BH3-1 060mBH3-2 690m




3reaches 3338


2 CaO Al

2O3 and SO

3contents For


2O3







Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl




Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl

BH1-0 2417 1910 437 3292 300 041 1082 039 417 025 005 009BH2-0 2034 1754 338 3327 250 036 2007 035 155 019 004 021BH3-0 2076 1565 315 3394 231 037 2220 023 092 015 004 012Average 2176 1743 363 3338 260 038 1770 032 221 020 004 014

LOI

SiO

2

Al2

O3

CaO

Fe2O

3

K2O

SO3

Na2

O

MgO

TiO

2

MnO Cl


0

10

20

30

40

50

Perc

ent m

ass b

y w

eigh

t (

)





2and CaCO




3


2 The set









2 (∘)

S4middot05（2

BH1-0

BH2-0

BH3-0

605040302010

３Ｃ2

3

(a)

BH1-1

BH1-2

BH1-3

BH1-4

2 (∘)605040302010

３Ｃ2

3

Ca (（)2

(b)

３Ｃ2

3

BH2-1

BH2-2

BH3-1

BH3-2

2 (∘)605040302010

Ca (（)2

(c)



2O3sdot3CaSO

4sdot32H2O)



3 and Al





4






(a) (b)


Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)




4



4



2O3sdot3CaSO





2O3sdot3CaSO


3CaOsdotAl2O3CaSO



2O3sdot3CaSO


(1)




2minus


2O 997888rarr CaSO

42H2O + 2OHminus


4



2sdotH2O

(2)





Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




6m0

BH1

BH2

BH3




BH1

BH1-0 0BH1-1 045mBH1-2 130mBH1-3 325mBH1-4 435m

BH2BH2-0 0BH2-1 040mBH2-2 570m

BH3BH3-0 0BH3-1 060mBH3-2 690m




3reaches 3338


2 CaO Al

2O3 and SO

3contents For


2O3







Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl




Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl

BH1-0 2417 1910 437 3292 300 041 1082 039 417 025 005 009BH2-0 2034 1754 338 3327 250 036 2007 035 155 019 004 021BH3-0 2076 1565 315 3394 231 037 2220 023 092 015 004 012Average 2176 1743 363 3338 260 038 1770 032 221 020 004 014

LOI

SiO

2

Al2

O3

CaO

Fe2O

3

K2O

SO3

Na2

O

MgO

TiO

2

MnO Cl


0

10

20

30

40

50

Perc

ent m

ass b

y w

eigh

t (

)





2and CaCO




3


2 The set









2 (∘)

S4middot05（2

BH1-0

BH2-0

BH3-0

605040302010

３Ｃ2

3

(a)

BH1-1

BH1-2

BH1-3

BH1-4

2 (∘)605040302010

３Ｃ2

3

Ca (（)2

(b)

３Ｃ2

3

BH2-1

BH2-2

BH3-1

BH3-2

2 (∘)605040302010

Ca (（)2

(c)



2O3sdot3CaSO

4sdot32H2O)



3 and Al





4






(a) (b)


Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)




4



4



2O3sdot3CaSO





2O3sdot3CaSO


3CaOsdotAl2O3CaSO



2O3sdot3CaSO


(1)




2minus


2O 997888rarr CaSO

42H2O + 2OHminus


4



2sdotH2O

(2)





Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl




Al2O3

CaO Fe2O3

K2O SO

3Na2O MgO TiO

2MnO Cl

BH1-0 2417 1910 437 3292 300 041 1082 039 417 025 005 009BH2-0 2034 1754 338 3327 250 036 2007 035 155 019 004 021BH3-0 2076 1565 315 3394 231 037 2220 023 092 015 004 012Average 2176 1743 363 3338 260 038 1770 032 221 020 004 014

LOI

SiO

2

Al2

O3

CaO

Fe2O

3

K2O

SO3

Na2

O

MgO

TiO

2

MnO Cl


0

10

20

30

40

50

Perc

ent m

ass b

y w

eigh

t (

)





2and CaCO




3


2 The set









2 (∘)

S4middot05（2

BH1-0

BH2-0

BH3-0

605040302010

３Ｃ2

3

(a)

BH1-1

BH1-2

BH1-3

BH1-4

2 (∘)605040302010

３Ｃ2

3

Ca (（)2

(b)

３Ｃ2

3

BH2-1

BH2-2

BH3-1

BH3-2

2 (∘)605040302010

Ca (（)2

(c)



2O3sdot3CaSO

4sdot32H2O)



3 and Al





4






(a) (b)


Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)




4



4



2O3sdot3CaSO





2O3sdot3CaSO


3CaOsdotAl2O3CaSO



2O3sdot3CaSO


(1)




2minus


2O 997888rarr CaSO

42H2O + 2OHminus


4



2sdotH2O

(2)





Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


2 (∘)

S4middot05（2

BH1-0

BH2-0

BH3-0

605040302010

３Ｃ2

3

(a)

BH1-1

BH1-2

BH1-3

BH1-4

2 (∘)605040302010

３Ｃ2

3

Ca (（)2

(b)

３Ｃ2

3

BH2-1

BH2-2

BH3-1

BH3-2

2 (∘)605040302010

Ca (（)2

(c)



2O3sdot3CaSO

4sdot32H2O)



3 and Al





4






(a) (b)


Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)




4



4



2O3sdot3CaSO





2O3sdot3CaSO


3CaOsdotAl2O3CaSO



2O3sdot3CaSO


(1)




2minus


2O 997888rarr CaSO

42H2O + 2OHminus


4



2sdotH2O

(2)





Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a) (b)


Energy (keV)

Ca Ca

O SAl

Si

1614121086420

(a)

CaCa

SKAl

SiFe

Fe

Ti

Energy (keV)1614121086420

(b)




4



4



2O3sdot3CaSO





2O3sdot3CaSO


3CaOsdotAl2O3CaSO



2O3sdot3CaSO


(1)




2minus


2O 997888rarr CaSO

42H2O + 2OHminus


4



2sdotH2O

(2)





Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Locations SO4

2minus (mgL) HCO3


4sdotCl-CasdotNa




Location CaCO3

CaSO4 2H2O CaMg(CO

3)2

Na2SO4

Na2SO4 10H2O MgSO

4 7H2O K

2SO4



5 Conclusions




3content




Acknowledgments


References





































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

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