STUDY ON THE DEVELOPMENT OF THE MUDDY SOIL HARDENING TREATMENT BY INDUSTRIAL WASTES AND THE EFFECTIVE USE OF THE TREATED SOILS

从建筑工地流出的泥质土（如hedoro）的数量一直在增加，其中一些被用作建筑材料。然而，1990年，中国每年未使用建筑垃圾的数量为7600万吨，其中约20%是受污染的污泥。各种工业废料也有同样的问题。从保护自然资源和减轻环境影响的角度来看，土壤和废物的再利用是非常重要的。本研究的目的是改善高含水量、高有机质泥质土的通航性或土方性，提高其强度。为了达到这些目的，在泥土中加入了硬化剂波特兰水泥和外加剂，并研究了它们的效果。所使用的外加剂是三种工业废料（混凝土粉、纸泥灰和煤粉煤灰）和一种天然材料（粒状膨润土）。结果表明：(1)掺加各种掺合料后，处理土的强度均有明显提高，并证实了掺合料与土的理想掺合比存在。(2)混凝土粉和纸泥灰作为掺合料对有机质少、含水量低的泥质土是有效的掺合料。例如，与仅混合水泥的土壤相比，混合纸污泥灰的处理土壤的强度增加了2-3倍。(3)在所有处理过的土壤中，由于钙矾石的产生，可乐粉煤灰获得了最大的硬化效果。掺有SO_3离子和火山灰物质的粉煤灰处理后的土强度是掺有纸泥灰的土强度的2倍。因此，粉煤灰可以被认为是“最合适的外加剂”。(4)膨润土在一定程度上受含水率降低和粘聚力增加的影响。(5)如果使用这些外加剂，在强度达到预期水平时，可以减少固化剂的用量，缩短固化时间。(6)用特殊掺合水泥处理土壤，从早期养护龄期到长期养护龄期均表现出较高的硬化强度。(7)对强度有贡献的硬化反应产物是CSH基团反应产物和钙矾石晶体。(8)强度较低，可进行无侧限压缩试验，可通过落锥试验估算。因此，可以预测长团队的强度，并利用该测试的结果对处理过的土壤进行质量控制。少

The amount of muddy soil such as hedoro from construction sites has been increasing, and some of them has been used as contruction material. However, the annual amount of unused construction waste was 76,000,000t in 1990, and about 20% of it was polluted sludge. Various inductrial wastes also have the same problem. It is very important to reuse the soil and waste, from the viewpoint of natural resource preservation and environmental impact mitigation.The purpose of this study is to improve the trafficability or earth-moving property and to increase the strength of muddy soil which is high in water content and organic matter. In order to achieve these objectives, a hardening agent Portland cement and the admixture were added to the muddy soil, and their effects investigated. The used admixtures are three types of industrial waste (concrete powder, paper sludge ash and coal fly ash), and one natural material (granular bentonite).The obtained results are summarized as follows :(1) It is m … More ade clear that the strength of the treated soil is enhanced with the addition of each of the used admixtures to the muddy soil, and it is confirmed that an ideal mixing ratio of admixtures and soil exists.(2) Concrete powder and paper sludge ash are effective as admixtures to muddy soil with less organic matter and low water content. For instance, the treated soil mixed with paper sludge ash became 2-3 times stronger compared with that only mixed cement.(3) Cola fly ash obtained the greatest hardening effective due to the production of ettringite in all treated soils. The strength of the treated soil mixed with the coal fly ash which contained SO_3 ion and pozzolanic material was twice that of the paper sludge ash mixing. Therefore, the coal fly ash can be considered "most suitable admixture".(4) Bentonite is affected to some degree by a reduction in moisture content and increased cohesion.(5) If these admixtures are used, it is possible to decrease the quantity of hardening agent used and to reduce the curing period when the strength achieves the expected level.(6) When the soil is treated with the special-blended cement, the high hardening strength can be observed from the early curing age through the long term.(7) The hardening reaction products which contribute to a strength are CSH group reaction products and ettringite crystals.(8) The strength, which is so low that the unconfined compression test can be performed, can be estimated by the fall cone test. It is consequently possible to predict the long team strength and to utilize the results of this test for a quality control of the treated soil. Less