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Detection of Drying‐Induced Microcracking in Cementitious Materials with Space‐Resolved 1 H Nuclear Magnetic Resonance Relaxometry
Author(s) -
Beyea Steven D.,
Balcom Bruce J.,
Bremner Theodore W.,
Armstrong Robin L.,
GrattanBellew Patrick E.
Publication year - 2003
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2003.tb03378.x
Subject(s) - relaxometry , cementitious , relaxation (psychology) , spin–lattice relaxation , nuclear magnetic resonance , materials science , mortar , spin–spin relaxation , magnetic resonance imaging , chemistry , spin echo , analytical chemistry (journal) , composite material , cement , chromatography , medicine , psychology , social psychology , physics , nuclear quadrupole resonance , radiology
Nuclear magnetic resonance (NMR) relaxation time mapping in partially dried mortar is presented. Relaxation times in concrete are typically multi‐exponential, and exhibit highly effective relaxation mechanisms ( T 1L ∼ 3 ms, Δν 1/2 ∼ 2500 Hz). One‐dimensional mapping of the spin–lattice relaxation time is used to study relative changes in the water‐occupied surface‐to‐volume ratio, as a function of mixture conditions, initial hydration period, and drying time. These results provide evidence for a penetrating microcracking phenomenon, due to local drying‐induced tensile stresses. This conclusion was further supported by a relaxation time study of samples which were preconditioned so as to be at equilibrium with various relative humidities.