Electrical conductivity of portland cement mortars

Peer reviewed: YesNRC publication: Ye

Thermodynamic properties of the Na-Bi-Pb system

Thermodynamic properties of Na in an equimolar Bi?Pb alloy were determined at 723 K for compositions of 0.0075 = XNa = 0.1000 from electromotive force measurements on Na metal concentration cells with a solid Na? f-Al2O3 electrolyte. A coulometric titration technique was used to electrochemically generate the Na metal in the Bi?Pb alloy. The results indicate that, as Na is added to Bi?Pb, the liquid becomes more associated and suggests complex species formation with an ionic character intermediate between those observed for the constituent binaries.Utilisant des mesures de la forme \ue9lectromotrice de cellules de Ia concentration du sodium m\ue9tallique avec un \ue9lectrolyte solide Na? f-Al2O3, on a d\ue9termine les propri\ue9t\ue9s thermodynamiques du sodium dans un alliage \ue9quimoleculaire de Bi-Pb, a 723 K, a des concentrations de 0,0075 = XNa = 0.1000. On a utilise une technique de titrage coulom\ue9trique pour g\ue9n\ue9rer le sodium m\ue9tallique dans l'alliage Bi-Pb d'une fa\ue7on \ue9lectrochimique. Les r\ue9sultats indiquent que, lorsqu'on ajoute du Na au Bi-Pb, le liquide devient plus associ\ue9 et sugg\ue8re qu'il y a formation d'esp\ue8ces complexes poss\ue9dant un caract\ue8re ioniqueInterm\ue9diaire entre celui observe pour les constituants binaires.Peer reviewed: YesNRC publication: Ye

Application of Danckwerts' solution to simultaneous diffusion and chemical reaction in concrete

Peer reviewed: YesNRC publication: Ye

Activities of dilute NiO in Na2O.2SiO2 by electromotive force measurements

Despite the industrial and theoretical significance of NiO De Khotinsky wax slags, there is a paucity of accurate thermodynamic data for these systems. The thermodynamic properties of NiO in calcium and sodium silicates have been studied (14). However, the thermodynamic properties of dilute solutions of NiO in silicate slag have not heretofore been reported. It was the purpose of the present study to investigate dilute solutions of NiO (XNiO < 0.0125) in Na20.2Si02. Dilute solutions are ideally ZrO2-CaO tube suited for understanding the effects of complex formation in silicates and the relationships between structure and thermodynamic properties. Furthermore, fundamental slag studies aid in the understanding and optimization of industrial pyrometallurgical processes.En d\ue9pit de l?importance industrielle et th\ue9orique des laitiers de paraffine NiO De Khotinsky, les donn\ue9es thermodynamiques pr\ue9cises pour ces syst\ue8mes demeurent peu abondantes. Les propri\ue9t\ue9s thermodynamiques de NiO dans les silicates de calcium et de sodium ont \ue9t\ue9 \ue9tudi\ue9es. Toutefois, on n?a pas jusqu?ici fait \ue9tat des propri\ue9t\ue9s thermodynamiques des solutions dilu\ue9es de NiO dans le laitier de silicate. Cette \ue9tude avait pour objet l?investigation de solutions dilu\ue9es de NiO (XNiO < 0,0125) dans Na20Peer reviewed: YesNRC publication: Ye

A Reply to a discussion by B. Batchelor of the paper "On the relationship between the formation factor and propan-2-ol diffusivity in mortars"

Peer reviewed: YesNRC publication: Ye

Immobilizing hazardous waste in cement

Aussi disponible en francais: Immobilisation de d\ue9 chets dangereux dans le cimentPeer reviewed: NoNRC publication: Ye

A rapid test for sulfate ingress into concrete

Peer reviewed: YesNRC publication: Ye

Rapid sulphate test method for concrete proves reliable

Aussi disponsible en fran\ue7ais: La tenue du b\ue9ton aux sulfates: une m\ue9thode d'essai rapide fait ses preuvesPeer reviewed: NoNRC publication: Ye

The Thermal decomposition of Ca(OH)2 polymorphs

The 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.On a investigu\ue9 la d\ue9composition thermique de diff\ue9rents polymorphes de Ca(OH)2 pr\ue9sentant divers degr\ue9s de cristallinit\ue9 et diverses aires de surface. Les valeurs d?aire de surface d?azote de Ca(OH)2 \ue9taient de 3,7 \ue0 31,1 m2/g. La pr\ue9sence de deux m\ue9canismes s\ue9par\ue9s et distincts de d\ue9composition thermique a \ue9t\ue9 observ\ue9e, suivant le degr\ue9 de cristallinit\ue9. Des m\ue9langes binaires de Ca(OH)2 ayant des degr\ue9s de cristallinit\ue9 consid\ue9rablement diff\ue9rents ont affich\ue9 des doublets de d\ue9composition thermique bien d\ue9finis. En outre, des exp\ue9riences d?analyse calorim\ue9trique \ue0 compensation de puissance (ACCP) (pour les cycles de chauffage et de refroidissement) men\ue9es dans des environnements contr\uf4l\ue9s pr\ue9conditionn\ue9s ayant diverses valeurs d?humidit\ue9 relative (HR) ont \ue9galement indiqu\ue9 la pr\ue9sence de deux doublets endothermiques distincts. Les temp\ue9ratures maximales endothermiques \ue9taient tributaires de l?historique des \ue9chantillons de Ca(OH)2 en mati\ue8re de HR et de temp\ue9rature. Une \ue9valuation des facteurs influant sur le comportement thermique observ\ue9 a englob\ue9 : l?investigation de la grosseur des particules et du degr\ue9 de cristallinit\ue9; l?observation de l?\ue9largissement combin\ue9 de la d\ue9formation par longueur unitaire et de la grosseur de particule (diagrammes de rayon X de Williamson-Hall); et les caract\ue9ristiques de capacit\ue9 thermique-temp\ue9rature. Une analyse thermodynamique du processus de d\ue9composition thermique est \ue9galement pr\ue9sent\ue9e.Peer reviewed: YesNRC publication: Ye

Solubility of CoCl2 in molten NaCl-AlCl3

Peer reviewed: YesNRC publication: Ye