000265408 001__ 265408
000265408 005__ 20190619041451.0
000265408 0247_ $$a10.5075/epfl-thesis-9321$$2doi
000265408 037__ $$aTHESIS
000265408 041__ $$aeng
000265408 088__ $$a9321
000265408 245__ $$aBasic creep and autogenous shrinkage of Limestone Calcined Clay Cement (LC3)
000265408 260__ $$aLausanne$$bEPFL$$c2019
000265408 269__ $$a2019
000265408 300__ $$a156
000265408 336__ $$aTheses
000265408 502__ $$aProf. Véronique Michaud (présidente) ; professeure Karen Scrivener (directeur de thèse) ; Prof. Eugen Brühwiler, Prof. Luca Sorelli, Prof. Viktor Mechtcherine (rapporteurs)
000265408 520__ $$aThe use of supplementary cementitious materials (SCM) to lower the clinker factor of cements is now commonplace, for it benefits performance, economics and ecology. This thesis focuses on ternary blends of limestone and calcined kaolinitic clays, two very promising SCM thanks to their worldwide availability. In particular, this research aims to get an insight on the delayed strains in sealed condition of such binders, christened LC3 for Limestone - Calcined Clay Cement. Delayed strains refer to time-dependent deformations undergone by the material during its lifetime, such as shrinkage and creep.
This work evaluates the impact of the calcined kaolinite content of the clay - which can vary in accordance with the origin of the clay - on the autogenous shrinkage and basic creep properties of LC3. Compressive creep tests on mature paste samples indicated that the presence of limestone and calcined clay dramatically reduced creep compliance. This reduction is significant even with lower grade clays and does not depend on the clay purity if it has at least 40% of calcined kaolinite. A two-dimensional finite elements model was used to simulate the creep response of the tested microstructures in order to try to determine whether the compliance reduction originated from a different phase assemblage or a higher viscosity of the C-S-H. The outputs pointed towards a different rheology of C-S-H gel. 
Autogenous shrinkage measurements on LC3 binders showed that these ternary blends had a lower or comparable shrinkage to plain cement reference during the two first months of hydration. Shrinkage rate and amplitude was found to be close for LC3 mixes usingmedium to high grade clays of natural origin. A study of the evolution of microstructure with shrinkage demonstrated that if the calcined clay contained enoughmetakaolin to consume most of the available portlandite, the porosity and desaturation of the microstructure were very similar regardless of the clay. As these features play a large role on the origin of shrinkage force, the macroscopic response is comparable among these specific mixes.
000265408 592__ $$b2019
000265408 6531_ $$aLimestone
000265408 6531_ $$acalcined clay
000265408 6531_ $$abasic creep
000265408 6531_ $$aautogenous shrinkage
000265408 6531_ $$amodelling
000265408 700__ $$aSton, Julien$$g170615
000265408 720_2 $$aScrivener, Karen$$edir.$$g138857
000265408 8564_ $$uhttps://infoscience.epfl.ch/record/265408/files/EPFL_TH9321.pdf$$s11902484
000265408 909C0 $$pLMC
000265408 909CO $$pSTI$$pthesis-public$$pDOI$$ooai:infoscience.epfl.ch:265408$$pthesis
000265408 918__ $$aSTI$$cIMX$$dEDMX
000265408 919__ $$aLMC
000265408 920__ $$a2019-05-03$$b2019
000265408 970__ $$a9321/THESES
000265408 973__ $$sPUBLISHED$$aEPFL
000265408 980__ $$aTHESIS