Impact of Thermal Stress on Abrasive Dust from a Carbon Fiber-Reinforced Concrete Composite

Recently, a novel corrosion-resistant construction material, Carbon Concrete Composite (C-3), consisting of coated carbon fibers embedded in a concrete matrix, was introduced. However, thermal exposure during domestic fires may impact the release of organic pollutants and fibers during abrasive processing and/or demolition. Consequently, the objective of this study was to explore the emission characteristics of toxic compounds and harmful fibers during the dry-cutting after exposure to 25-600 degrees C (3 h, air). These parameters mimic the abrasive machining and dismantling after a domestic fire event. Mass spectrometry and chromatography served as analytical methodologies, and no organic pollutants for exposure temperatures >= 400 degrees C were found. In contrast, significant amounts of pyrolysis products from the organic fiber coating were released at lower temperatures. Studying the morphology of the released fibers by electron microscopy revealed a decrease in fiber diameter for temperatures exceeding 450 degrees C. At >= 550 degrees C, harmful fibers, according to the World Health Organization (WHO) definition, occurred (28-41 x 10(3) WHO fibers/m(3) at 550-600 degrees C). This leads to the conclusion that there is a demand for restraining and protection measures, such as the use of wet cutting processes, suction devices, particle filtering masks and protective clothing, to handle thermally stressed C-3.