Behavior evaluation of self- compacting concrete exposed to elevated temperature
The Journal of Environmental studies (JES)
Vol. (13), 8 pages
Author:Ammar ' Khazaal
This paper presents an experimental study on the performance of self-compacted concrete (SCC) subjected to elevated temperature. Two SCC mixtures were tested. Microstructural properties were studied at ambient temperature and after heating. For each test, the specimens were heated at a rate of 1 C°/min up to different temperatures (150, 300, 450 and 600 C°). In order to ensure a uniform temperature throughout the specimen, the temperature was held constant at the target temperature for one hour before cooling. In addition, the specimen mass was measured before and after heating in order to determine the loss of water during the test. The results allowed us to analyze the degradation of SCC due to heating. Between 20 and 150 °C, it was associated to an evaporation of free water as well as to an increase in porosity of the tested concretes. Between 150 and 300 °C, in a similar way to the observed evolutions between 20 and 150 °C, due to the departure of bound water, corresponding to a large mass loss. The improvement in microstructure could be attributed to a modification of the bonding properties of the cement paste hydrates (rehydration of the paste due to the migration of water in the pores). Beyond 300 °C, the microstructure of the tested concretes deteriorated quickly. The specimens subjected to a heating up to 600 °C showed very weak physical properties (appearance of microcracking).
Self-compacted concrete, microstructure, heating and cooling.