Experiment On High Early Strength And Stabilizing Of Municipal Dredging Sludge

Much dredging sediment occurred in the dredgeing projects of rivers, ports and lakes in China. It does great harm to the surrounding environment where it was dumped. With high organic matter content, high water content, high compressibility and low intensity, the dredging sediment can cause the yard foundation poor stability and strength shortage. Therefore, such dredging sediment needs to be solidified. The solidified soil can be used as materials for dyke strengthening works, road engineering and reclamation engineering. Targeting at the material and chemical compositions of the dredging sludge as breakthrough point, through indoor physical, chemical and mechanical test of the solidifying material, the controllability research on the strength and solidification time of the dredging silt in the early stage should be carried out. The evolution characteristic of the dredging silt during the process of early solidification will be discussed from the microstructure perspective.The main work and conclusions are listed as follows:1. On the basis of relative research and the characteristics of silt, considering of economy and practicability, several solidification additives are selected.2. The solidification effect of single and compound solidification material are systemically studied, the optimical compound solidification material proportion is gained. The tests indicate that adding proper gypsum into cement could improve the soil curing early strength. What's more, its effect is better than adding fly ash.3. The comparative researches on solidification effect with different water content curing by different material with different combination are made, the solidification law of diferent material adulterate proportion and curing age and water content is discussed.4. Based on the sample-made technology of the liquid nitrogen freeze-dry, samples of sludge have been prepared. By means of scan electron microscope (SEM) technology, the microstructure images of the sludge improvement with curing agent are obtained. The sludge microstructure parameters are studied by a program developed by the MATLAB language. The sludge microstructure after curing by different curing agent have been analysised preliminarily.5. The achievements of this study are summarized; the later tasks are also prospected.