Frostbetinget salttransport - en ny holdbarhedsteknologi / Frost Induced Salt Transport - a New Durability Technology

Gennem litteraturstudier, teoretiske analyser og laboratorieforsøg sigter projektet på at undersøge den dynamisk statistiske karakter af isdannelser i hærdnet cementpasta og herunder kortlægge de saltbevægelser og saltkoncentrationsprofiler, der fremkaldes af ensidige, cykliske frost-tø belastninger. I projektet indgår en analyse af de termodynamisk kontrollerede faseligevægte, der optræder i en saltholdig porevæske i et hygroskopisk system. Som led i projektet udvikles en ny måleteknik, (CTS: Continuous Temperature Scanning), til bestemmelse af temperaturfordelingen i endimensionalt frysende prøveemner. Projektet indeholder herudover en implementeringsfase, hvorunder man vil søge at anvende de opnåede resultater ved udvikling af frostprøvningsmetoder. Erhvervsforsker ph.d.-projekt EF-757. Deltagere/Interessenter: Betoncentret, Teknologisk Institut; Cement- og Betonlaboratoriet, Aalborg Portland A/S; Institut for Bærende Konstruktioner og Materialer, DTU. Herudover indgår et samarbejde med Afdelingen for Bygningsmaterialer, Lunds Tekniska Högskola. (M. Tange Jepsen, P. Freiesleben Hansen) Through literature studies, theoretical analyses and laboratory tests, the dynamic statistic nature of ice formation in hardened cement paste is investigated, and the transport of salts and salt concentration profiles created by unilateral, cyclic frost-thaw loads are mapped. An analysis of the thermodynamically controlled phase equilibrium in saline pore solution in a hygroscopic system is also included in the project. As part of the project, a new measuring technique (CTS: Continuous Temperature Scanning) for determination of the temperature distribution in one-dimensional freezing test specimens is developed. Further, the project includes an implementation phase, where the results obtained during the project will be applied to development of frost testing methods. Participants/interested parties: The Concrete Centre at the Danish Technological Institute, the Cement and Concrete Laboratory at Aalborg Portland, the BYG-department at the Technical University of Denmark. Furthermore, cooperation with the Department of Building Materials at Lund Institute of Technology. Industrial Ph.D. project (EF-757). (M. Tange Jepsen, P. Freiesleben Hansen)