循环流化床燃煤固硫灰的CBR特性及膨胀机理研究  

CBR Characteristics and Expansion Mechanism of Circulating Fluidized Bed Fly Ash

作　　者：王杰 王勇 王宇强 王彩萍[4] 叶圣茂 高鹏 WANG Jie;WANG Yong;WANG Yuqiang;WANG Caiping;YE Shengmao;GAO Peng(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;Lvliang National Highway Project Construction Management Co.,Ltd.of Shanxi Road and Bridge Group,Lvliang 033000,China;Changzhi Wuli Engineering Technology Research Institute,Changzhi 046000,China;School of Materials Science and Engineering,North University of China,Taiyuan 030051,China;Jinneng Holding Power Group Co.,Ltd.,Taiyuan 030051,China)

机构地区：[1]武汉理工大学材料科学与工程学院,武汉430070 [2]山西路桥集团吕梁国道项目建设管理有限公司,吕梁033000 [3]长治市武理工工程技术研究院,长治046000 [4]中北大学材料科学与工程学院,太原030051 [5]晋能控股电力集团有限公司,太原030051

出　　处：《硅酸盐通报》2023年第4期1323-1332,共10页Bulletin of the Chinese Ceramic Society

摘　　要：循环流化床燃煤固硫灰(CFB飞灰)加水自硬,能够形成强度较高的固结体,具备做路基的潜质,但CFB飞灰中的f-CaO和Ⅱ-CaSO4水化生成钙矾石和二水石膏体积膨胀,可能会对路基体积稳定性产生影响。因此本文研究了标准养护时间、CFB飞灰的硫钙含量、压实度对CFB飞灰固结体加州承载比(CBR)值、吸水率和CBR膨胀率的影响规律及CFB飞灰在干硬性体系下的膨胀机理。结果表明:CFB飞灰固结体的膨胀主要来源于CFB飞灰的吸水膨胀和水化膨胀;标准养护时间越长,固结体CBR值越大,吸水率和膨胀率越低,标准养护7 d时CBR值、吸水率趋向于稳定,膨胀率不再变化;CFB飞灰的硫钙含量越高,固结体CBR值越大,膨胀稳定时间越长,稳定后的膨胀率越高,吸水率越低;压实度增大,固结体孔隙率降低、密实度增加,CBR值逐渐增大,吸水率降低,对膨胀的约束作用增强,膨胀率逐渐降低。Circulating fluidized bed fly ash(CFB fly ash)can form a high-strength solidified body by adding water to harden itself and has the potential to be used as roadbed.However,the hydration of f-CaO and II-CaSO4 in CFB fly ash to form ettringite and dihydrate gypsum causes the volume expansion of the solidified body,which may affect the volume stability of the subgrade.Therefore,the effects of standard curing time,sulfur and calcium content of CFB fly ash and compactness on California bearing ratio(CBR),water absorption and CBR expansion rate of CFB fly ash solidified body were studied in this paper.And the expansion mechanism of CFB fly ash in dry and hard system was studied.The results show that the expansion of CFB fly ash solidified body mainly comes from the water absorption expansion and hydration expansion of CFB fly ash.The longer the standard curing time is,the larger the CBR value of the consolidated body and the lower the water absorption and expansion rate are.The CBR value and water absorption rate tended to be stable and the expansion rate did not change at 7 d of standard curing.The higher the sulfur and calcium content of CFB fly ash is,the larger the CBR value of the consolidated body,the longer the expansion stability time,the higher the expansion rate after stabilization,and the lower the water absorption rate are.With the increase of compactness,the density of solidified body increases and porosity decreases.Therefore,the CBR increases gradually and the water absorption gradually decreases.Due to the increase of the constraint effect of CBR on the expansion,the expansion rate of the solidified body decreases gradually.

关 键 词：CFB飞灰 固结体 水化膨胀 吸水膨胀 钙矾石 二水石膏 

分 类 号：U414[交通运输工程—道路与铁道工程]