Study of the decalcification process in mortars degraded by NH4NO3 by using ultrasonic techniques

Autor: I. Segura, A. Moragues, D. E. Macphee, J. J. Anaya, M. Molero
Jazyk: English<br />Spanish; Castilian
Rok vydání: 2009
Předmět:
Zdroj: Materiales de Construccion, Vol 59, Iss 296, Pp 17-36 (2009)
Druh dokumentu: article
ISSN: 0465-2746
1988-3226
DOI: 10.3989/mc.2009.46008
Popis: Water takes part in most if not all of the degradation processes experienced by cement-based materials during their service-life. The effect of pure water usually is not of primary concern as it involves very lengthy degradation diffusion controlled processes; aqueous solutions are more aggressive, promoting increased solubility of matrix components and microstructure modification due to leaching. The ability to monitor such changes nondestructively presents a number of challenges as, often, conventional characterisation techniques require sample preparation likely to modify the properties of interest. In this study, ultrasonic pulse velocity profiles have provided a nondestructive means of monitoring microstructural changes during aggressive leaching of blastfurnace slag cement mortars with ammonium nitrate solutions. These data are compared with corresponding analyses by destructive techniques including mercury intrusion porosimetry (MIP), water porosity measurements, X-ray diffraction (XRD) and scanning electron microscopy (SEM). By analysing degraded ultrasonic velocity profiles it has been possible to calculate degraded depths in the samples, which correlate well with those results obtained by conventional methods.
Databáze: Directory of Open Access Journals