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Quality Risk Assessment Of Water - Soluble Hexavalent Chromium In Cement And Risk Assessment

Posted on:2014-07-09Degree:MasterType:Thesis
Country:ChinaCandidate:M F JiangFull Text:PDF
GTID:2271330431471456Subject:Materials engineering
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Cement products contain cadmium, chromium, lead, copper, zinc, nickel and other heavy metals and these materials will gradually release in the long-term use due to their exposure to water, soil and atmosphere and will have a negative influence on environmental safety and human health. Among those, water-soluble chromium (VI) is a main source of toxicity of cement. In recent years, the pollution of water-soluble chromium (VI) is attached great importance. According to the EU Directive2003/53/EC, the use and sale of cements and related products with water-soluble chromium (VI) of more than0.0002%(mass fraction) are prohibited. Therefore, the research on the investigation of quality and safety risk and risk assessment of water-soluble chromium (VI) has the important theoretical significance and practical value.The water-soluble chromium (VI) content and the28days compressive strength of100batches of cement (each50batches of cement of strength grade32.5and42.5) were tested in this thesis. The result shows that high concentration of water-soluble chromium (VI) in cement products is a common phenomenon. The higher strength grade, the larger water-soluble chromium (VI) content in cement products. The injury severity of cement samples collected in this risk survey is "very serious", and the possibility of injury is above1‰(the injury possibility of cement of strength grade32.5is5.0%o,and the cement of strength grade42.5is14.0%o).
Keywords/Search Tags:the water-soluble chromium(â…¥) content of cement, quality and safety risk, risk assessment
PDF Full Text Request
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