关键词: 给水污泥, 免烧砖, 抗压强度, 协同利用, 微观结构

Abstract: High value resource utilization of water supply sludge is an important means to improve the fine management of solid wastes. The dewatered sludge from three urban water treatment plants with Qingcaosha reservoir， Jinze reservoir and Chenhang reservoir as the water source was taken as the research object. The experiment of making non-sintered specimen by water supply sludge with recycled aggregate from construction and demolition debris was carried out. The influence of the sludge content， sludge moisture content， water binder ratio， sludge composition and other factors on the compressive strength of non-sintered specimen was studied. And the leaching toxicity of heavy metals and microstructure analysis were also examined. The results showed that the strength of non-sintered specimen was affected by the variation of sludge composition caused by season and sludge source， which showed that winter was better than summer， and Chenhang reservoir had the highest strength among the three. The optimum proportion of materials was 20% of cement， 20% of sludge， 25% of recycled coarse aggregate， 35% of recycled fine aggregate， and the water content of sludge was 70%. The compressive strength of non-sintered specimen curing for 28 days reached 15 MPa， and the strength grade reached MU15 in GB/T 8239—2014 Normal Concrete Small Block. The analysis results of scanning electron microscope （SEM） showed that the structure of sludge-aggregate-cement became denser and more stable with the increase of curing time under the optimal conditions. The leaching toxicity of As in the heavy metal leaching experiment was much lower than the value stipulated in the GB 5085.3—2007 Identification Standards for Hazardous Wastes： Identification for Extraction Toxicity， and the environmental safety met the requirements.

Key words: water supply sludge, unburned specimen, compressive strength, collaborative utilization, microstructure