The Thermal decomposition of Ca(OH)2 polymorphs

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ConferenceRILEM - 2nd International Symposium on Advances in Concrete Through Science and Engineering: 11 September 2006, Québec City
Pages115; # of pages: 15
Subjectthermal decomposition, calcium hydroxide, crystallinity, thermodynamics; Concrete
AbstractThe thermal decomposition of different polymorphs of Ca(OH)2 with varying degrees of crystallinity and surface area was investigated. The nitrogen surface area values ranged from 3.7 to 31.1 m2/g. The presence of two separate and distinct thermal decomposition events was observed depending on the degree of crystallinity. Binary mixtures of Ca(OH)2 with substantially different degrees of crystallinity exhibited well defined thermal decomposition doublets. In addition Differential Scanning Calorimetry (DSC) experiments (for cycles of heating and cooling) performed in controlled environments pre-conditioned to various relative humidities (RH) also indicated the presence of two distinct endothermal doublets. The endothermic peak temperatures were dependent on the RH and temperature history of the Ca(OH)2 samples. An assessment of factors affecting the observed thermal behavior included: investigation of particle size and degree of crystallinity; observation of combined strain and particle size broadening (Williamson-Hall X-ray plots); heat capacity-temperature characteristics. A thermodynamic analysis of the thermal decomposition process is presented.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedYes
NRC number46310
NPARC number20377090
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Record identifierbedec8af-029a-4fe9-96e3-55790cfbb648
Record created2012-07-24
Record modified2016-05-09
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