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

建筑工地产生的黑土等淤泥质土数量一直在增加，其中一些已被用作建筑材料。然而，1990年未利用的建筑垃圾每年为7600万吨，其中约20%是受污染的污泥。各种生活垃圾也存在同样的问题。从保护自然资源和减轻环境影响的角度来看，土壤和废弃物的再利用是非常重要的。本研究的目的是改善高含水率和高有机质的淤泥质土的通过性或移土性，增加强度。为了达到这些目的，在淤泥质土中加入了固化剂硅酸盐水泥和外加剂，并研究了它们的效果。所使用的外加剂是三种工业废渣(混凝土粉、纸浆灰和煤粉)和一种天然材料(颗粒膨润土)。结果表明：(1)它是m…进一步研究表明，在淤泥质土中加入不同的外加剂均能提高土的强度，存在一个理想的外加剂与土的配合比。(2)对于有机质含量较低、含水率较低的淤泥质土，混凝土微粉和纸浆灰是有效的外加剂。例如，掺入造纸污泥灰的处理土的强度是单纯掺入水泥的2-3倍。(3)在所有的处理土中，由于产生了钙矾石，可乐灰的硬化效果最好。掺入含有SO3离子和火山灰物质的煤粉的处理土的强度是掺入纸泥灰的两倍。(4)膨润土在一定程度上受到含水率降低和粘聚力增加的影响。(5)如果使用这些外加剂，有可能减少硬化剂的使用量，并在强度达到预期水平时缩短养护时间。(6)用特殊掺入的水泥处理土壤时，从早期养护到长期养护，都可以观察到很高的硬化强度。(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，它很低，可以进行无侧限压缩试验，可以通过落锥试验来估计。因此，可以预测长期队伍的强度，并利用这次试验的结果来控制处理后的土壤的质量。较少

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