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Though cement is a ubiquitous material with global production exceeding that of any other material of technologicalimportance, the mechanism of its hydration and evolution of cement-water mixtures into gels of high compressivestrength is poorly understood, despite extensive research over the past century. Recent investigations, based onneutron scattering measurements, aims at unraveling this enigma and outlines, for the first time, the evolution ofthe mesoscopic structure of the cement paste which exhibits temporal oscillations, strongly dependent on the scaleof observation and on the medium of hydration (light or heavy water). While the formation of hydration productsis synchronous for hydration with H2O, the process is non-synchronous for hydration with D2O. The reason whymorphological patterns of domains at different times look dissimilar, as seen before (Phys. Rev. Lett. 93, 255704 (2004);Phys. Rev. B. 72, 224208 (2005)), for different hydration media emerges as a natural consequence of this finding.Mesoscopic structure of cement paste exhibits isotope effect. The structures arise from well-characterised chemicalreactions as water diffuses through the porous material to bring about the water-surface interactions within the complexlocal geometry. The noteworthy observations point to the effect of hydrogen bonding on mesoscopic structure resultingfrom hydration although hydrogen bond with deuterium is only slightly stabler yielding a longer lifetime vis-a-vis bondinvoving hydrogen. Aforementioned investigations also provide an explanation for disagreement with the hypothesis ofdynamical scaling for hydration of cement with heavy water and is a step forward towards general understanding ofhydration process.
References
[1] S. Mazumder, et al., Phys. Rev. Lett 93 (2004) 255704.
[2] S. Mazumder, et al., Phys. Rev. B 72 (2005) 224208.
[3] S. Mazumder, et al., Phys. Rev. B 76 (2007) 064205.
[4] S. Mazumder, et al., Phys. Rev. B 82 (2010) 064203.
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