Microstructure aspects of self-compacting concrete at elevated temperature: Fid-Bau Portal

Microstructure aspects of self-compacting concrete at elevated temperature

Ye, G. / Liu, X. / De Schutter, G. / Taerwe, L. / Yuan, Y.

A compilation of fire test data has shown distinct behavioral differences between high performance concrete and traditional concrete at elevated temperature. The differences in fire behaviour are largely depending on the microstructural properties, especially on the porosity, pore size distribution and the connectivity of pores. Self-compacting concrete, as a new smart building material with varies advanced properties, has been used for a wide range of structures and infrastructures. However the microstructure changes of self-compacting concrete at elevated temperature are not investigated. In this contribution, the microstructure changes of self-compacting concrete at elevated temperature are examined by mercury intrusion porosimetry and scanning electron microscopy. The chemical de-composition of self-compacting concrete at different temperatures is determined by thermogravimetric analysis. (1) The total porosity and the critical pore diameter increase with the position closer to the heating face. (2) According to different water to powder ratio, self-compacting concrete shows a higher change or at least the same change of the total porosity in comparison with HPC. (3) Presence of polypropylene fibers can dramatically reduce the damage of microstructure when concrete is exposed to fire. (4) TGA/DTA experiments indicate that the samples made with SCC shows a better stability below 700 deg C. However, when the temperature is higher than 700 deg C, a dramatic loss of mass was observed in the SCC samples. This also confirms that SCC will probably show larger damage once exposed to fire.