循环流化床灰渣水稳基层强度及形成机理研究

Study on Strength and Formation Mechanism of Water-stable Base Course of Ashes and Slags in Circulating Fluidized Bed

为了探究循环流化床(CFB)灰渣(CFB粉煤灰和CFB炉渣合称CFB灰渣)在水稳基层材料中的应用,本文在测定CFB灰渣物化特性的基础上从CFB炉渣-机制砂替代率、CFB粉煤灰掺量、养护龄期、不同龄期水溶液pH值以及结合料过度界面水化情况研究CFB灰渣对水稳基层材料无侧限抗压强度的影响。研究结果表明:水泥-CFB炉渣7 d无侧限抗压强度最高为3.8 MPa,较水泥稳定碎石降低了37.3%,7 d~90 d无侧限抗压强度增长率为85.3%。水泥-CFB灰渣7 d无侧限抗压强度最高为6.8 MPa,较水泥稳定碎石提高了11.5%,7 d~90 d无侧限抗压强度增长率为58.8%。CH含量随着龄期的增长呈现先升高后降低的趋势。CFB灰渣主要水化产物为针棒状AFt、长柱状CaSO_(4)·2H_(2)O和纤维状C-S-H。水泥-CFB炉渣中胶凝物质生成量低于水泥-CFB灰渣。

To explore the circulating fluidized bed(CFB)ash(CFB fly ash and CFB slag are collectively called CFB ash slag)in the application of cement stabilized base materials,based on the determination of CFB ash in CFB furnace slag-mechanism on the basis of physical and chemical characteristics of sand replacement ratio,dosage of CFB fly ash and curing age,different age aqueous solution pH value and binder interface hydration case study effect of CFB ash on unconfined compressive strength of water stable base material.The results show that the maximum unconfined compressive strength of cement-CFB slag at 7 d is 3.8 MPa,which is 37.3%lower than that of cement-stabilized crushed stone.The growth rate of unconfined compressive strength at 7 d~90 d is 85.3%.The maximum unconfined compressive strength of cement-CFB ash at 7 d is 6.8 MPa,which is 11.5%higher than that of cement stabilized machete,and the growth rate of unconfined compressive strength from 7 d to 90 d is 58.8%.CH content increased firstly and then decreased with age.The main hydration products of CFB ash residue are needle-rod AFt,long columnar CaSO_(4)·2H_(2)O and fibrous C-S-H.Cementitious substance production in cement-CFB slag is lower than cement-CFB ash slag.