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SWrucWural Analysis of HisWorical ConsWrucWions – Jerzy Jasieńko (ed) © 2012 DPNH ProcławH PolandH ISSN 0860-2395H ISBN 978-83-7125-216-7

fksbpTfdATflk lk AaebobkCb CeAoACTbofpTfCp lc ilt-pTobkdTe MloTAop rpba fk Teb aAMAdba efpTlofCAi MAplkoY pTorCTrobp aaniel CovatariuNI Mihai BudescuO ABpToACT qhe paper presents some experámentally results concernáng the estámatáon of the load bearáng capacáty of the low-strength mortars masonry dependáng on mechanácal characterástács of the mortar and fráctáon force between bráck and mortar. qhere are consádered mortar máxes from tradátáonal materáals EclayI lámeFI áts mechanácal characterástács and an ámportant attentáon was gáven to adherence between masonry páeces EbráckF and bánder Elow-strength mortarsF. qhe obtaáned results show that a correct behaváour estámatáon of the damaged masonry could be obtaáned wáthout tests whách ánvolve elaborated methods. heywords: iowJstrength mortarI MasonryI criction forceI ptrength characteristics NK fkTolarCTflk ptructural and archátectural maántenance are preventáve countermeasures taken to avoád any cause of degradatáon on hástorácally or archátecturally remarkable buáldángs. jasonry walls are the maán focus of thás concern. rnreánforced masonry walls often present ánadequacáes of ultámate capacátáes andLor serváceabáláty performancesI resultáng from defácáencáes due to lateral load varáatáon Efrom seásmác loadsFI deteráoratáonI constructáon or deságn errors. ioad bearáng walls are sensátáve to lateral cyclác actáonsI whách may cause sudden loss of capacáty and bráttle faálure due to ánstabálátyX ánfáll panels are also susceptáble to pulláng apart from floors or snap through duráng earthquakes or blastáng shocks xPI 4z. fn order to restore the orágánal structural functáon of already damaged masonry membersI testáng and rehabálátatáon technáques usually requáre delácate retrofát that could even be detrámental áf a dásturbáng process ás ánvolved. iow-ámpact approaches based on nonántrusáve and non-destructáve methods of rehabálátatáon are án demand when ánduced or potentáal damages are fundamental ássues xRz. cor these reasonsI a testáng method whách could estámate the behaváour of the damaged masonry walls only knowáng the mechanácal characterástác of the materáals could have a ságnáfácant ámportance duráng buáldáng testáng operatáons. qhe successáve laboratory experámental program áncludes a prelámánary materáal characterázatáonI adherence ánvestágatáons and wall testáng. Centrác and dáagonal compressáon tests are performed on dáfferent mortar máxes low-strength-mortar EipjF masonry specámens án order to ádentáfy the ánfluence of dáfferent combánatáons of mortars. marameters such as mechanácal characterástács of the compounded materáalsI fráctáon forces between mortars and brácksI manufacture condátáons are evaluated xTz.

N penáor iecturerI mh.a.I “dheorghe Asachá” qechnácal rnáversáty of fasáI caculty of Cávál bngáneeráng

and Buáldáng pervácesI aepartment of Cávál and fndustráal ConstructáonsI covadan]ce.tuáasá.ro O cull mrofessorI mh.a.I “dheorghe Asachá” qechnácal rnáversáty of fasáI caculty of Cávál bngáneeráng

and Buáldáng pervácesI aepartment of ptructural jechanácsI mbudescu]ce.tuáasá.ro

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OK MATbofAip Aka bXmbofMbkTAi pbT-rm

qhe experámental program was aámed to the behaváour evaluatáon of the masonry specámens made from ordánary clay bráck EjRF bounded wáth low strength mortars xpo bk NMRO-NWOMMNz. po that the dáfferentáatáon on the structural elements types was realásed by dáfferent mortar máxes. qhree máxes of mortar were used xsee cág. NzI made wáth varáous bánders and a standard cement-based mortar máx Efor controlFW

– jN. Control máx EjRwF Cement EN unátF – pand E4 unátsF – jO. jáx O – iáme paste EN unátF – pand EP unátsF – jP. jáx P – Clay paste EN unátF – pand EP unátsF – j4. jáx 4 – iáme paste EN.R unátsF – Cement EM.R unátsF – pand ES unátsF

qhe laboratory test has as a purpose the determánatáon of the materáal’s characterástácsI and also centrác and dáagonal compressáon strength on the masonry specámens. qhe tests were developed on P dárectáonsW

N. jechanácal determánatáons on the compounded materáals Ebánder – cementI láme and clayI aggregate – sandF and the masonry’s components mechanácal characterástács – on brácks and mortars E4 máxesFX

O. qest ánvolváng adherence between brácks and mortarsX P. ptatácally determánatáons on masonry specámens EwallsFW centrác and dáagonal compressáon tests.

cigK N jortar jáxes ppecámen OKNK The masonry’s components mechanical characteristics – bricks and mortars

aF bendáng tensále test bF compressáon test cigK O Brácks testáng

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Table N qests results on brácks

oated dámensáons O4M × NNR × SM mm Apparent densáty NURM kgLmP

Compressáon strength NMUIMR dakLcmO

Bendáng tensále strength RMIOUP dakLcmO

Table O qests results on mortars

iaboratory determánatáons jáx N jáx O jáx P jáx 4 N. Consástency R.R V S.R T.R O. Apparent densáty xkgLmPz NRTS NUOT NVRM NTTM

4. Compressáon strength xdakLcmOz VT.US O4.VT OR.TU OP.PP

R. Bendáng tensále strength xdakLcmOz M.4OP – – – OKOK aetermination of mortar adherence to masonry pieces EbricksF ft ás well known that the mortar ás more deformable than the masonry blockI haváng the tendency to slung out of joántsI but agaánst thás tendency comes the masonry block by áts fráctáonal and adherence forces that exást between them. po thatI án the endI thás dáfference of transversal deformabáláty produces unát tensále stresses án the masonry block. As the most ánterventáons to rehabálátate the bráck masonráes depend on the cooperatáon between ánterventáon elements EmortarF and masonry supportI át was consádered useful to reváew the mortar adherence to bráckwork. tas consádered two sátuatáons on adherence testángW

aF pulláng-out testX bF shear test.

Because the testáng method from shear ás not standardázedI a deváce was suggested and executedI made based on the frame and práncáple of crühláng – jáchaelás xsee cág. Pz deváceI to whách át was added a unát formed by a metallác yoke Edestáned to fáx the bráck on the deváce baseF and a steel ráng H adjustáng screw assembly Edestáned to exercáse the tensále force generatáng a shearáng force at the support ánterface Ebráck and mortar tabletF.

aF pull-out test

bF shear test

cigK P Aspects duráng determánatáons

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crom the results dáagrams xcág. 4 and RzI the followáng observatáons are necessaryW – qhe results from pull-out test was not conclusáveI the fráctáon force beáng very small takáng to

consáderatáon the fráctáon force from shear and was not consádered as followsX – qhe best behaváour has EobváouslyF the máx jN and the fráctáon force’s lower value was

regástered for jP máx Eclay mortarFX qhe j4 máx Eláme-cement mortarF has an áncreased value of the fráctáon force – compared wáth jO máxI because of the cementátáous compounds.

cigK 4 saráatáon of the pull-out force for dáfferent types of mortar

cigK R saráatáon of the shear force for dáfferent types of mortar OKPK ptatic determination on masonry specimens Eaccordáng to po bk NMRO-NWOMMNF qestáng programs on masonry elements was performed on masonry walls s ET4M × O4M × TOM mmF made from clay brácks O4M × NNR × SP and 4 ánátáal máxes xcág. Sz. qhe horázontal and vertácal mortar joánts has NM mm wádth. qhe manual labour has a normal qualáty standard.

cigK S jasonry specámen model

qhe test was performed wáth a hydraulác testáng macháneI usáng mechanácal dásplacements sensors. qhe fássure’s evolutáon was recorded on photos. tas tested R elements for each máx and was selected the results from best P of áts xcág. T and Uz.

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cigK T Centrác compressáon test cigK U aáagonal compressáon test OKPK1 Centric compression specimen’s testing qhe tests were performed by a OM specámens lot. All specámens were loaded untál the ultámate faálure state. fn cágure V are shown the behaváour of the tested specámens.

cigK V qested specámens – fássures and cracks

draphácally representatáons of the test results xcágure NMz are shown án dáagram and are relevant the follows remarksW

– qhe bággest strength to compressáon was determáned at jN specámensI recordáng also the smallest dásplacement. qherefore results a good behaváour to hágh stresses but haváng a “breakable” behaváourX

– Could be observed that the cement quantáty án j4 máx áncrease the faálure force valueI and án the same táme decreasáng the dásplacements values. qhe faálure force ás comparable wáth the jO máx force valueI but the dásplacement wáll be reduced wáth aprox. 4OBX

– qhe “weakest” behaváour has the jP specámens Eclay based mortarFI but also the most deformable Ehaváng the bággest deformatáonI double confronted wáth jN based specámensFX

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ft ás ánterestáng to comment the appearance manner of the fássuresW at the jN based specámensI the fássures suddenly appearsI are transmátted parallel wáth propagatáon dárectáon of the force and not necessary on the joánts Ebecause of the strength of the mortar and brácks – aprox. equal – the specámen functáon láke a monoláthF. ln contrary the fássures produced on jO and jP based specámensI becomes vásáble lately Eon bág dásplacements and occur after a preváously expulsáon of the mortar from joántsFI followáng precásely the joánts.

cigK NM corce – dásplacements dáagram obtaáned for the tested specámens – centrác compressáon test

OKPKOK aiagonal compression specimen’s testing qhe tests were performed also by a OM specámens lot. All specámens were loaded untál the ultámate faálure state. fn cágure NN are shown some aspects duráng the tests. qhe dásplacements were recorded wáth O mechanácal sensorsI one for each vertácal and horázontal dárectáon Elu şá lvF..

cigK NN qested specámens – dáagonal compressáon

cigK NO corce – dásplacements dáagram obtaáned for the tested specámens made wáth dáfferent mortar máxes – dáagonal compressáon test

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PK ClkCirpflkp qhe results obtaáned xcág. NM and NOz was ánterpreted as followsW

– qhe best behaváour had the j4 mortar Ej4F thatI unláke those executed wáth jN mortarI has an deformabáláty reserve Edue to the láme used as a bánderFX

– qhe presence of cement quantáty EORBF án j4 mortar máx áncrease about Pu the faálure force unláke the value recorded for jO mortar faálure Emortar only wáth lámeFX

– qhe cement mortars EjNF have a fraál behaváour and collapse wáthout bág fássures X – qhe poorest structure was proved to be the one executed from clay mortar EjPF thatI due to the

poor adherence between mortar and masonry stoneI faáls almost ánstantly. – All the specámen behaváour duráng the centrác and dáagonal compressáon tests was sámálar due to

adherence tests and has comparatáve value Eproportáonally order sázeF wáth the mortar’s compressáon strength.

AChkltibadbMbkTp qhás paper was supported by the project “aevelop and support multádáscáplánary postdoctoral programs án prámordáal technácal areas of natáonal strategy of the research – development – ánnovatáon” 4a-mlpqalCI contract nr. mlpaorLUVLN.RLpLROSMPI project co-funded from buropean pocáal cund through pectoráal lperatáonal mrogram euman oesources OMMT-OMNP. obcbobkCbp xNz CpA ANTV-M4I CpA ECanadáan ptandards AssocáatáonF EOMM4F “jortar and drout for rnát

jasonry”. xOz CoS – Cod de proáectare pentru structurá dán zádăráe EOMMSF xPz iuque A.I Cultrone d. and pebastáán b EOMNMF “qhe rse of iáme jortars án oestoratáon tork on

Archátectural eerátage”I pp. NVT-OMVI án “MaterialsI Technologies and mractice in eistoric eeritage ptructures”I ppránger pcáenceHBusáness jedáa B.s.

x4z mleşu o.I Ţăranu d.I Covataráu a.I drădánaráu f.a. EOMNNF ptrengthenáng and oehabálátatáon Conventáonal jethods for jasonry ConstructáonI The Bulletin lf The molytechnic fnstitute lf gassyI ConstructionK Architecture pectionI qommeW isff xiufzI cascácleW 4I pp. NSR-NTS.

xRz Budescu j.I ş.a. ENVUOF jateráal testángI Technical mublishing eouseI BucharestI cap. ONI pp. PUV-4NR.

xSz molCbjA p.A. Bucharest ENVVVF fnvestágatáon methodology of old masonráes – ándex jmMMT-VV xTz Covataráu a.I qoma f.l.I mleşu o.I Budescu j. EOMNNF A ptudy on jortar Adherence to jasonry

máeces fn Case of eástorácal BuáldángsI fn fCbrBfOM11 – fnternational Conference on bngineering rBf OM11 – „fnnovation and aevelopment”I OU-PM nov OMNNI CoválhaI mortugal paperW CqT-N4.

xUz Apqj CNPRT-MV EOMMVF “ptandard qest jethods for bvaluatáng jasonry Bond ptrength”. xVz Apqj CTUM-NM EOMNMF “ptandard qest jethod for mreconstructáon and Constructáon bvaluatáon

of jortars for mlaán and oeánforced rnát jasonry”. xNMz Apqj COTM-NM EOMNMF “ptandard ppecáfácatáon for jortar for rnát jasonry”. xNNz bks-N-NI burocode SW aeságn of masonry structures – mart N-NW deneral rules for buáldángs –

oules for oeánforced and rnreánforced jasonry.