MULTIPLE HEADSPACE EXTRACTION GAS CHROMATOGRAPHY FOR QUANTIFICATION OF VOC'S IN CONCRETE

摘要

Concrete itself is not a source of VOC emissions of any importance. However, humid concrete is very alkaline and may cause degradation of organic materials. Concrete can also adsorb considerable amounts of volatile compounds, e.g. from degrading flooring materials. This together with the present trends in cement and concrete production (alternative fuels, new organic additives, waste materials) has made it interesting to develop rapid methods for quantification of VOCs in concrete. We have tested a multiple headspace extraction gas chromatography method to determine the VOC content of cement bound materials. The total VOC content of a sample may be calculated from repeated headspace injections. The sample incubation time and temperature were optimized for six organic compounds with different boiling points and polarity. The method is tested on samples with known additions of these six organic compounds. The method works well on relatively dry samples, but there are problems with over-pressure in the headspace vial from water vapor in humid samples.