循环流化床燃煤固硫灰改良云南红粘土

Improving typical laterite in Yunnan province with recycled fly ash from coal-fired circulating fluidized bed combustion with in-furnace desulfurization

为因地制宜寻求适合固硫灰大掺量利用的新途径,解决固硫灰滞销的问题,提高固硫灰的综合利用率,利用固硫灰具有游离氧化钙含量高、火山灰特性、自硬性的特点,将其掺入红粘土进行土质改良,开展土工实验,以满足高速路基填筑材料技术要求为指标,确定适宜的固硫灰掺入量。结果表明：在红粘土中掺入适量固硫灰,能够有效降低塑性指数、增强压实性、提高承载比,固硫灰掺入量为30%以内,CBR可提高至5%以上,符合路床土最小强度要求;当固硫灰掺入量为10%~20%时,CBR可提高至15%以上,符合高速公路路床土最小强度要求。在红粘土中掺入适量固硫灰,能够有效改良红粘土,当固硫灰掺入量为10%~20%时,改良红粘土用作高速公路路床土在技术上是可行的。

The goal of this investigation is to look for a new way to improve the utilization ratio of desulfurization ash,which is yield from coal-fired fluidized bed combustion. Desulfurization ash has three characteristics：high content of free calcium oxide,pozzolanic activity and self-hardening activity. In this investigation,desulfurization ash was blended with laterite to modify laterite＇s performance,in order to meet the strength qualification of subgrade material for highway. And then optimum addition of desulfurization ash was determined. The results showed that： after blending with appropriate amount of desulfurization ash,laterite has a lower plasticity index,a better compatibility,and a higher california bearing ratio. While the addition is less than 30%,its california bearing ratio（ CBR） can be increased to 5%,and then modified laterite can be used for road bed soil. While the addition is between 10% to 20%,california bearing ratio can be increased to 15%,and modified laterite can be used for subgrade material of highway.