| With the development of the substructure building in our country, the amount of concrete consuming is increasing continuously and the exploitation of mine resource results in the serious damage of the natural environment. At the same time, the utilization rate of fly ash, especially the low quality ones is still very low and sludge are still not used and treated with well, which results in environmental pollution. This paper studies and prepares high strength light aggregate that can take place of the natural aggregate and even the natural gravel aggregate with the raw material of fly ashes and city sludge and sludge. This study can not only make use of the fly ash and sludge well but also possess very important meaning for saving source and energy and ensuring the sustainable development.The ideal structural model of high performance lightweight aggregate was set up in this paper combined the achievement received in the research work on high performance lightweight concrete. Regarding the ideal structure model as guidelines, we adopt the dynamic expanding in earlier stage for the main fact, in order to form through holes, reduce unit weight; Relying mainly on expanding in static behavior on later stage to cram and feed through holes through the liquid phase material, adjust and optimize the structure of hole, we successfully improved the strength and reduced the hole rate. Through the two-combined expanding model organically, the ideal structure of lightweight aggregate was formed. Cooperate with the solid burning technology and mullite crystallizing technology together with optimizing raw materials and sintering system, the hole structure and composites of lightweight aggregate was adjust, and its problem of low strength and high water absorption rate were solved.On the basis of analyzing the component, physical elemental analyzing, the range of Intenerated temperature of fly ash and sludge, this research experimented and studied the proportion of the raw materials, and then ascertained the optimized proportion. By adopting SEM, XRD, DTA and TG, combining the result of macro performance, the law of impact coursed by concerned factors on the performance of lightweight aggregate is summoned, which suggests that the optimized proportion of fly ash to sludge is 4:6. The industry has produced the high quality light aggregate whose strength is 7.4MPa and the water absorptive ration is 8.5%, which is accorded to the standard of the perfect production according to the national standard GB/T17431.1-1998.A evaluation model for the green degree of both process schemes and the products is set up based on the product quality, level of the cost, resource consuming and environment pollution during the manufacturing course of lightweight aggregate. The results based on this model reveals that the high performance lightweight aggregate manufactured according to the research work in this paper has an obvious highly relative degree of green. |
