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全球变暖是当今社会面临的主要环境问题,是由过量二氧化碳排放造成的。水泥生产过程中石灰石的分解和燃料的燃烧排放的CO_2量占据了总排放的5%~8%。随着民用基础设施建设的快速发展,特别是在中国、印度、中东等发展中国家,水泥和混凝土使用量飞速增长。采用辅助胶凝材料替代混凝土中水泥的使用量,尤其是工业废弃物,能够显著降低了混凝土生产过程中的碳排放。普通的工业废弃物,如硅灰、粉煤灰、矿粉等并不是全部可以利用的,较远距离运输会造成CO_2总排放量的增加。然而,铝生产工业的其他副产物和废弃纸泥灰也可以作为辅助胶凝材料进行循环利用的。农业生产中的废弃物,如甘蔗灰、棕榈油灰、椰子壳灰、稻壳灰等也有火山灰特性,能够将其作为辅助胶凝材料使用。此外,一些天然掺合料,如硅藻土含有丰富的火山灰活性组分。近年来,玻璃粉作为辅助胶凝材料在很多国家广泛应用。上述辅助胶凝材料的循环利用能够降低混凝土对环境影响,且能有效减少相关生产费用。
Global warming is the main environmental issue facing society today, caused by excess carbon dioxide emissions. In the process of cement production, the decomposition of limestone and the burning of fuel CO 2 accounted for 5% -8% of the total emission. With the rapid development of civilian infrastructure construction, cement and concrete are used rapidly in developing countries such as China, India and the Middle East. The use of ancillary cementitious materials to replace cement in concrete, especially industrial waste, can significantly reduce carbon emissions from concrete production. Ordinary industrial waste, such as silica fume, fly ash, slag and so on, are not all available. Transporting over longer distances will result in an increase in CO 2 total emissions. However, other by-products of the aluminum production industry and waste paper dust can also be recycled as an auxiliary cementitious material. Waste from agricultural production such as sugar cane ash, palm putty, coconut shell ash, rice husk ash and others also have pozzolanic properties that can be used as an auxiliary cementitious material. In addition, some natural admixtures, such as diatomaceous earth, are rich in pozzolanic active ingredients. In recent years, glass powder as an auxiliary cementing material is widely used in many countries. The recycling of the above auxiliary cementitious materials can reduce the environmental impact of concrete and can effectively reduce the related production costs.