Thermal properties, environmental deterioration and applications of macro-defect-free cements

Macro-Defect-Free (MDF) cements using the blends of sulfoaluminate ferrite belite (SAFB) clinkers and ordinary Portland cement (OPC) in mass ratio 85 : 15 and hydroxypropylmethyl cellulose (HPMC) or polyphosphates (poly-P) were subjected to various moist atmosphere to investigate their environmental deterioration. Their thermal decomposition studies were also carried out before and after moisture attack. The effect of individual relative humidity (RH) on moisture resistance of MDF cements is more intensive than the effects of composition of MDF cements or duration of the original MDF cements synthesis. There are three main temperature regions on TG curves of both series of MDF cement samples (before and after moisture attack). In the inter-phase section of MDF cements, the content of classical cement hydrates (CSH, gypsum, AFm and AFt phases) decomposing by 250 oC is increased, while the content of cross-links section and Ca(OH)2 with typical thermoanalytical traces in temperature range 250 - 550 oC remains almost identical before and after moisture attack. In the temperature range 550 - 800 oC, decomposition of CaCO3 is occurred. Some important applications of MDF cements also have been reviewed in this work*.On a expos\ue9 des ciments MDF (Macro-Defect-Free) pr\ue9par\ue9s \ue0 partir de m\ue9langes de ciments clinkers \ue0 retrait compens\ue9 \ue0 phases ferrite et belite (SAFB) et de ciment Portland ordinaire (CPO) selon un rapport massique de 85 : 15, et d?hydroxypropylm\ue9thyl cellulose (HPMC) ou de polyphosphates (poly-P) \ue0 divers degr\ue9s d?humidit\ue9 atmosph\ue9rique, dans le but d?en \ue9tudier la d\ue9t\ue9rioration dans l?environnement. Des \ue9tudes de leur d\ue9composition thermique ont \ue9t\ue9 r\ue9alis\ue9es \ue9galement, avant et apr\ue8s l?exposition \ue0 l?humidit\ue9. L?incidence de l?humidit\ue9 relative (HR) individuelle sur la r\ue9sistance \ue0 l?humidit\ue9 des ciments MDF est plus marqu\ue9e que celle de la composition de ces ciments ou de la dur\ue9e de la synth\ue8se des ciments MDF d?origine. On note trois (3) principales r\ue9gions de temp\ue9rature sur les courbes de TG de l'une et l'autre s\ue9ries d'\ue9chantillons de ciment MDF (avant et apr\ue8s l?exposition \ue0 l?humidit\ue9). Dans la section interphase des ciments MDF, la teneur en hydrates classiques du ciment (C-S-H, pl\ue2tre, phases AFm et AFt) se d\ue9composant \ue0 250 oC est augment\ue9e, tandis que le contenu de la section de r\ue9ticulation et de Ca(OH)2 avec traces thermoanalytiques dans la plage de 250 oC \ue0 550 oC demeure presque le m\ueame avant et apr\ue8s l?exposition \ue0 l?humidit\ue9. Dans la plage de 550 oC \ue0 800 oC, la d\ue9composition de CaCO3 est survenue. Dans ces travaux, on examine \ue9galement certaines applications importantes des ciments MDF.Peer reviewed: YesNRC publication: Ye