Processing-moisture resistance and thermal analysis of macro-defect-free materials

The system of sulfoaluminate ferrite belite (SAFB) clinkers premixed with P ortland cement (PC) in mass ratio 85:15 in combination with hydroxypropylme thyl cellulose (HPMC) or polyphosphates (poly-P) was used for the syntheses of Macro-Defect-Free (MDF) materials. The subsequent moisture treatment an d thermal stability of these MDF materials were investigated. The effect of individual humidity upon the evolution of mass is more intensive than the effects of composition of MDF materials or duration of the original MDF mat erial synthesis. Detailed values of mass changes at 100% relative humidity (RH) and under ambient conditions are strongly affected by the nature of po lymer used. A significant improvement of moisture resistance of MDF materia ls is achieved when the materials are dried after 24 h of finishing the pre ssure application. In the inter-phase section of MDF material samples, the content of C-(A,F)-(S) over bar hydraulic phases, mainly tetracalcium alumi nate ferrite monosulphate hydrate (AFm) decomposing by 250 degreesC and CaC O3 decomposing at 600-700 degreesC increase after the moisture attack, whil e cross-links in AFm-like section with typical thermoanalytical traces in t emperature region 250-550 degreesC remain intact.**