Improvement of soft soil using cementitious additives is a widely practiced technique in the construction industry. However, cement mixing is considered to be an expensive technique and this research has attempted to study the use of an industrial waste; flyash to improve a drinking water treatment sludge. Flyash is a fine, glass powder recovered from the gases of burning coal during the production of electricity at Norochchole, thermal power plant in Sri Lanka. The larger amount of drinking water treatment sludge which is a very soft clayey soil, is disposed into the environment without acquiring any benefit. Use of flyash in improving soft soils such as sludge with a low maximum dry density and low CBR will solve few burning issues such as dumping of flyash and sludge, health issues due to disposal of flyash and sludge, difficulties to find soils with better properties for road constructions and other construction related applications. Identifying the characteristics of the sludge, studying the variation of maximum dry density and optimum moisture content with flyash content, strength gain with time, and the applicability of the improved soil in the industry are the key findings and observations of this study. It was observed that the optimum proportion of the flyash to be added to the sludge to achieve a remarkable gain in its properties is around 30% of its dry weight. Acceptable CBR value was achieved after 7 days curing followed by standard 4 days soaking period.

中文翻译：

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用粉煤灰改善饮用水处理污泥的土壤特性

使用水泥添加剂来改善软土是建筑行业中广泛实践的技术。然而，水泥混合被认为是一种昂贵的技术，这项研究试图研究工业废物的使用。粉煤灰，以改善饮用水处理污泥。粉煤灰是一种细小的玻璃粉，是在斯里兰卡热电厂Norochchole发电时从燃烧煤的气体中回收的。大量的饮用水处理污泥（一种非常柔软的黏土）被排放到环境中而没有任何收益。使用粉煤灰改良软土，例如最大干密度低，CBR低的污泥，将解决一些燃烧问题，例如粉煤灰和污泥的倾倒，粉煤灰和污泥处置带来的健康问题，难以找到具有更好性能的土壤以用于道路建设和其他与建筑相关的应用。识别污泥的特性，研究最大干密度和最佳水分随粉煤灰含量的变化，强度随时间的变化以及改良土壤在工业中的适用性是这项研究的主要发现和观察结果。据观察，为获得显着的性能增加而添加至污泥中的粉煤灰的最佳比例约为其干重的30％。固化7天后再经过标准的4天浸泡时间，即可达到可接受的CBR值。研究最大干密度和最佳水分含量随粉煤灰含量变化，强度随时间变化以及改良土壤在工业中的适用性是这项研究的主要发现和观察结果。据观察，为获得显着的性能增加而添加至污泥中的粉煤灰的最佳比例约为其干重的30％。固化7天后再经过标准的4天浸泡时间，即可达到可接受的CBR值。研究最大干密度和最佳水分含量随粉煤灰含量变化，强度随时间变化以及改良土壤在工业中的适用性是这项研究的主要发现和观察结果。据观察，为获得显着的性能增加而添加至污泥中的粉煤灰的最佳比例约为其干重的30％。固化7天后再经过标准的4天浸泡时间，即可达到可接受的CBR值。