Free,restrainedanddryingshrinkageofcementmortar compositesreinforcedwithvegetablefibres RomildoD.ToledoFilho a, * ,KhosrowGhavami b , MiguelA.Sanjua ´n c ,GeorgeL.England d a Department of Civil Engineering, COPPE, Federal University of Rio de Janeiro, P.O. Box 68506, CEP: 21945-970, Rio de Janeiro, Brazil b Department of Civil Engineering, PUC-Rio, Rua Marque ˆs de Sa ˜o Vicente, 225, Ga ´vea, CEP: 22453-900, Rio de Janeiro-RJ, Brazil c Instituto Espan ˜ol del Cemento y sus Aplicaciones, C/Jose ´ Abascal, 53. 28003 Madrid, Spain d Department of Civil Engineering, Imperial College of Science Technology and Medicine, Imperial College Road, SW7 2BU London, United Kingdom Abstract Manyinvestigationsarerealizedtoestablishthebasicmechanicalpropertiesofvegetablefibrereinforcedcomposites(VFRC)but nottheirshrinkageandcreepbehaviour.Someworkshavebeenrealizedtoestablishtheshrinkageofcementmortarmatricesrein- forcedwithcellulosefibres,butveryfewresultshasbeenpublishedwithregardstoshrinkageofVFRCwithshortsisalandcoconut fibres.Inthispaperaconcisesummaryofseveralinvestigationsispresentedtoestablishtheinfluenceofsisalandcoconutfibreson thefreeandrestrainedplasticshrinkage,earlydryingshrinkagecracking,crackself-healingandlong-termdryingshrinkageofmor- tarmatrices.Thefreeandrestrainedshrinkagewerestudiedbysubjectingthespecimenstowindspeedof0.4–0.5m/sat40 °Ctem- peratureforupto280min.TheselfhealingofcracksoftheVFRCwasstudiedbyusingthesamespecimensasforthestudyof restrainedshrinkagewhichwerekeptfurtherinacontrolledenvironmentwith100%relativehumidityandtemperatureof21 °C forupto40days.Dryingshrinkagetestswerecarriedoutatroomtemperaturewithabout41%relativehumidityfor320days. Theinfluenceofcuringmethod,mixproportionsandpartialreplacementofordinaryPortlandcement(OPC)bygroundgranulated blast-furnaceslagandsilicafumeonthedryingshrinkageofVFRCwasalsoinvestigated.Finally,basedontheobtainedresultson dryingshrinkageanequationusingtherecommendationofACImodelB3wasadjustedandcomparedwellwiththeobtainedexper- imentaldata. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Sisalfibres;Coconutfibres;Cement;Mortar;Compositematerials;Plasticshrinkage;Shrinkagecracking;Self-healingofcracks;Drying shrinkage 1. Introduction Plastic shrinkage is the dimensional change that oc- cursinallfreshcementbasedmaterialswithinthefirst fewhoursafterplacementwhenthemixtureisstillplas- tic and has not yet achieved any significant strength. Freshly cast concrete shrinks primarily due to water evaporation. This shrinkage has been attributed [1,2] to negative capillary pressure that leads to a volume contractionofthecementpaste.Thestressesaregener- atedbyacomplexseriesofmenisciwhichareformedin thewaterfilledconcreteporeswhenwateriseliminated fromthepastemainlybyevaporation. If concrete is restrained against shrinkage, tensile stress develops and can cause cracks. Plastic shrinkage cracks are widely evident in bridge decks, industrial and parking garage floors and highway pavement slabs,thathavelargethicknessandexposedareas.The 0958-9465/$-seefrontmatter Ó 2004ElsevierLtd.Allrightsreserved. doi:10.1016/j.cemconcomp.2004.09.005 * Correspondingauthor.Tel.:+5502125628479;fax:+550212562 8484. E-mail address: toledo@coc.ufrj.br (R.D.ToledoFilho). Cement&ConcreteComposites27(2005)537–546 www.elsevier.com/locate/cemconcomp