000185547 001__ 185547
000185547 005__ 20180913061837.0
000185547 0247_ $$2doi$$a10.1016/j.cemconres.2012.10.001
000185547 022__ $$a0008-8846
000185547 02470 $$2ISI$$a000313850200010
000185547 037__ $$aARTICLE
000185547 245__ $$aMechanism of expansion of mortars immersed in sodium sulfate solutions
000185547 260__ $$aOxford$$bPergamon-Elsevier Science Ltd$$c2013
000185547 269__ $$a2013
000185547 300__ $$a7
000185547 336__ $$aJournal Articles
000185547 520__ $$aThe mechanisms behind the expansion of samples immersed in solutions containing sulfate ions have been controversial. Expansion is believed to originate in the formation of ettringite, but it is not possible to find any direct correlation between these two processes or to relate expansion purely to the increase in solid volume. Crystallization pressure is considered to be the most likely mechanism. A key aspect of this mechanism is the existence of supersaturation in the solution with respect to the growing crystal and it is not possible to directly measure the composition of the pore solution at different points within the specimen. In this paper we present a refinement of the crystallization pressure hypothesis to explain sulfate related expansion. We provide evidence that expansion is related to the transformation of monosulfate crystals embedded in the C-S-H to ettringite. Initially incoming sulfate reacts with aluminate containing hydrates in large pores to give ettringite without expansion. During this process the composition of the solution is buffered by the precipitation of solids so the rate of ingress does not depend strongly on the solution composition. After all this "freely available" aluminate has reacted, the concentration of sulfate ions in the pore solution increases, as indicated by the rise of sulfate absorbed on C-S-H. When the solution concentration reaches a critical level it provides the driving force for the precipitation of ettringite crystals in small pores within the C-S-H. Due to the confinement and the supersaturation of the solution this formation of ettringite leads to expansion of the paste. (C) 2012 Elsevier Ltd. All rights reserved.
000185547 6531_ $$aExpansion
000185547 6531_ $$aEttringite
000185547 6531_ $$aSulfate attack
000185547 6531_ $$aCrystallization pressure
000185547 700__ $$aYu, Cheng$$uSoutheast Univ, Sch Mat Sci & Engn, Jiangsu Key Lab Construct Mat, Nanjing 21189, Jiangsu, Peoples R China
000185547 700__ $$aSun, Wei$$uSoutheast Univ, Sch Mat Sci & Engn, Jiangsu Key Lab Construct Mat, Nanjing 21189, Jiangsu, Peoples R China
000185547 700__ $$0244030$$aScrivener, Karen$$g138857$$uSoutheast Univ, Sch Mat Sci & Engn, Jiangsu Key Lab Construct Mat, Nanjing 21189, Jiangsu, Peoples R China
000185547 773__ $$j43$$q105-111$$tCement And Concrete Research
000185547 909C0 $$0252300$$pLMC$$xU10341
000185547 909CO $$ooai:infoscience.tind.io:185547$$pSTI$$particle
000185547 917Z8 $$x184559
000185547 937__ $$aEPFL-ARTICLE-185547
000185547 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000185547 980__ $$aARTICLE