LABORATORY AND FIELD EVALUATIONS OF RECYCLED GYPSUM AS A STABILIZER AGENT IN EMBANKMENT CONSTRUCTION
LABORATORY AND FIELD EVALUATIONS OF RECYCLED GYPSUM AS A STABILIZER AGENT IN EMBANKMENT CONSTRUCTION
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DOI：
10.3208/sandf.51.975
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发表时间：
2011-12-01
影响因子：
3.7
通讯作者：
Kamei, Takeshi
中科院分区：
文献类型：
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作者：
Ahmed, Aly;Ugai, Keizo;Kamei, Takeshi
日本每年生产约160万吨石膏废石膏板。因此，必须找到一种替代方法来减少这种废物的数量，以避免环境问题和填埋处置的高成本。本文介绍了一个案例研究的重点是使用再生石膏，这是来自石膏废石膏板，以提高软粘土强度的路堤建设项目考虑到环境影响。研究了四种不同的再生石膏含量，范围从0到10%。两种不同类型的水泥波特兰和炉渣类型B的含量范围从0到3%，用于开发固化回收石膏和改善环境性能。为此，进行了一系列的无侧限压缩试验，以评估处理粘土的强度性能。同时通过一系列环境试验，研究了氟、硼和六价铬在未处理和处理土壤中的溶解度浓度。此外，硫化氢和pH值进行了研究。结果表明，随着再生石膏掺量的增加，处理后粘土的抗压强度和容重均增加。在现场获得的强度与回收石膏处理的土壤被认为是大于在实验室中获得的。土-石膏混合料的早期养护龄期对强度性能的影响显著大于后期养护龄期。再生石膏对试验土的强度有明显的增强作用。这是改善路堤通过性的重要特性，有助于减少施工时间和成本。在调查范围内使用再生石膏对pH值没有不利影响，硫化氢气体低于标准允许限值。此外，氟、硼和六价铬的溶解度浓度在日本允许的标准限度内。养护时间对降低有害物质释放量有显著影响。B型炉水泥具有改善土壤-石膏混合物的力学和环境功能的潜力。推荐使用B型炉水泥作为再生石膏处理土壤的固化剂，因为它成本低，而且比波特兰水泥更环保。
Approximately 1.6 million tons of gypsum waste plasterboard are produced annually in Japan. As such, it is essential to find an alternative way to reduce the quantities of this waste material to avoid environmental problems and the high cost of disposal in landfill. This paper describes a case study focused on the use of recycled gypsum, which is derived from gypsum waste plasterboard, to improve the strength of soft clay soil for embankment construction projects taken in consideration environmental impacts. Four different recycled gypsum contents ranging from 0 to 10% was investigated. Two different types of cements Portland and Furnace slag type B with a content ranging from 0 to 3% was used to develop solidification for recycled gypsum and improve environmental properties. For this purpose, a series of unconfined compression tests were conducted to evaluate strength performance of treated clay. While a series of environmental tests were conducted to explore the solubility concentration of fluorine, boron, and hexavalent chromium in the untreated and treated soil specimens. Furthermore, hydrogen sulfide and pH were investigated. Results showed that compressive strength and unit weight of treated clay soil increased with the increase of recycled gypsum content. The strength obtained in the field for treated soil with recycled gypsum was found to be greater than that obtained in the laboratory. The early curing days for soil-gypsum mixture had a significant effect on strength performance compared to the later days. The additives of recycled gypsum for tested soil swiftly increased the strength. This is a vital property for improvement embankment trafficability that helps to reduce the construction time and cost. The use of recycled gypsum within the investigated limits had no adverse effect on pH value and hydrogen sulfide gas was found to be less than the standard permitted limits. As well, the solubility concentrations for fluorine, boron, and hexavalent chromium were found within the permitted standard limits in Japan. The curing time had a significant effect on the reduction the release of harmful substance elements investigated. Furnace cement type B had the potential to improve the mechanical and environmental functions for soil-gypsum mixture. It is recommended that Furnace cement type B be used as a solidification agent for soil treated with recycled gypsum because it has low cost and it is more environmentally friendly than Portland cement.