Mechanisms of salt frost scaling on portland cement-bound materials: studies and hypothesis
Author
Summary, in English
Results are reported from a study of chloride ion penetration into hardened Portland cement paste over short periods, 0.5-3 hours. A simple relation, based on the Kozeny-Carman equation, between the transport coefficients and the porosity and specific surface of the material is presented.
A study of the differential sorption enthalpy and differential sorption entropy was carried out using a recently developed sorption calorimeter. The results cover the range 0-95% relative humidity at +25°C. Desorption isotherms were determined at 5° and 18°C by drying samples over saturated salt solutions. Freezing calorimetry tests were conducted on the same materials. The results from the room temperature experiments were used to calculate what heat flow rates were to be expected during the melting phase of the freezing calorimetry tests. These calculated heat flow rates are lower than those actually obtained. It is hypothesised that this is due to unintentional carbonation of the samples used for determination of the desorption isotherms and thus the calculated amount of water melting at a certain temperature is too low. The results though indicate that ice formation takes place mainly through successive drying of the micro pores.
Department/s
Publishing year
1998
Language
English
Publication/Series
Report TVBM
Volume
1017
Full text
Document type
Dissertation
Publisher
Division of Building Materials, LTH, Lund University
Topic
- Materials Engineering
Keywords
- Deterioration
- Durability
- Freeze-Thaw
- Frost
- Salt
- Mechanism
- Chloride
- Diffusion
- Adsorption
- Building construction
- Cement
- Concrete
- Byggnadsteknik
Status
Published
Supervisor
- [unknown] [unknown]
ISBN/ISSN/Other
- ISSN: 0348-7911
- ISBN: 91-628-3285-9
- ISRN: LUTVDG/TVBM--98/1017--SE(1-266)
Defence date
17 December 1998
Defence time
13:15
Defence place
Room V:A, John Ericssons väg 1, LUND
Opponent
- Vesa Penttala (Prof.)