【摘要】 城市疏浚河道清出的淤泥,含水量大、有机质含量高、气味臭、有时还含有有毒有害物质,如何进行无害化、资源化处理成为当前城市可持续发展的重要研究课题。以南京秦淮河中段清淤工程为例,以其清出的淤泥为原料,添加一定比例粘性土,淤泥与粘性土比例分别为1∶1、3∶2和7∶3的3组砖坯试样,在1 000、1 050和1 100℃3个不同温度下进行烧结制砖试验。分别测试了烧成品试样的烧失率、线收缩率、吸水率、抗压强度等物理力学参数,并利用XRD和SEM研究了烧成品的微观结构特征,综合分析了粘性土含量和烧结温度对淤泥进行资源化处理效果的影响。研究结果表明:烧结温度对试样烧结效果影响显著,当烧结温度为1 100℃时,3组试样均出现过烧现象,1 050℃比较接近试样的适宜烧结温度;粘土含量逐渐增加,烧成品物理力学性质逐渐改善,当粘土含量增加到50%,烧结温度为1 050℃时,砖块体积密度为1.4g/cm3、吸水率为17.28%、线收缩率为-0.5%、抗压强度为12.56Mpa,具有轻质保温特性,各项性能均能够满足工程建设有关规范对普通砖的要求。研究结果对城市景观河道疏浚淤泥的资源化处理具有参考价值。更多还原

【Abstract】 The dredged material of urban river(DMUR) is of high water content、rich in organic matter、smelly odor and sometimes also contains toxic and hazardous substances.Harmless and resource utilization of DMUR became an important research topic of urban sustainable development.In this study,the dredging project of Nanjing Qinhuai River were taken for example,the DMUR and clay were used as raw materials to produce sintered brick.Percentages of DMUR in raw materials range from 50% to 70% by mass ratio,and brick specimens sintered at kiln temperatures of 1 000℃、1 050℃ and 1 100℃.In order to analyze the impact of clay content and kiln temperature on the sintered specimens,mechanical tests were performed to measure bulk density,weight loss on ignition,shrinkage,water absorption and compressive strength;Chemical compositions and microstructures of the samples were investigated using X-ray diffraction(XRD) and scanning electron microscopy(SEM),respectively.The results indicate that the kiln temperature has significant effects on sintered specimens,1 050℃ is the suitable kiln temperature for these specimens;when the clay content is gradually increased,the physical and mechanical properties of sintered specimens gradually increased.Under the optimum preparation condition(DMUR content of 50%,the sintering temperature is 1 050 ℃),bulk density,water absorption,the linear shrinkage,compressive strength of the sintered bricks were 1.4 g/cm3,17.28%,-0.5%,12.56 MPa,respectively,meeting the requirements of common bricks.The results of the study have references significant for resource utilization of DMUR.更多还原