摘要
针对沥青道路用钢渣集料的安定性不良问题,研究了碳酸化钢渣的沥青混合料体积膨胀率的变化规律,探讨了碳酸化钢渣中f-CaO含量和压蒸粉化率的变化规律和相互关系,利用背散射电子成像(BSE)、扫描电子显微镜(SEM)结合X射线能谱(EDS)分析了碳酸化钢渣的微观形貌。结果表明:在CO_(2)初始压力1.0 MPa下,温度低于90℃碳酸化主要消解钢渣中活性f-CaO,生成的立方体状CaCO_(3)颗粒尺寸较大且均匀,碳酸化钢渣中f-CaO含量与其压蒸粉化率呈直线下降相关。温度高于90℃和时间长于9 h碳酸化制度可完全消解4.75~9.5 mm钢渣中的活性f-CaO,同时逐渐消解f-MgO或RO相,致使碳酸化钢渣的压蒸粉化率直线下降;并且促使大颗粒聚集矿物向小尺寸分裂和重排,促进短簇状的夹杂MgCO_(3)、FeCO_(3)等物质的CaCO_(3)生成。最终,碳酸化温度高于90℃和时间长于9 h可从根本上解决钢渣安定性不良的问题,其沥青混合料养护3 d体积膨胀率(约0.97%)低于标准值(1.5%)的35%,6 d膨胀率(约1.16%)趋于平稳并低于标准值的23%,达到了碳酸化钢渣沥青混凝土具有长期良好稳定性的目的。
Aiming at the unsoundness problem of steel slag aggregates for asphalt roads,the volume expansion rate of the asphalt mixture for carbonated steel slag was studied.The variation and relationship between f-CaO content and autoclaving pulverization rate in carbonated steel slag were investigated.The micro-morphology of carbonated steel slag was analyzed by BSE(Back Scattered Electron),SEM(Scanning Electron Microscope)and EDS(Energy X-ray Dispersive Spectroscopy).The results show that the active f-CaO in steel slag is mainly digested by carbonation below 90℃ under 1.0 MPa CO_(2) initial pressure,and the cubic CaCO_(3) particles are big size and uniform.The content of f-CaO in carbonated steel slag decreases linearly with its autoclaved pulverization rate.The active f-CaO in 4.75~9.5 mm steel slag can be completely digested by the carbonation system with temperature higher than 90℃ and time longer than 9 h,and the f-MgO or RO phase can be gradually digested,resulting in a linear decrease in the autoclave pulverization rate of carbonated steel slag.It also promotes the splitting and rearrangement of large aggregate minerals to small size and promotes the formation of CaCO_(3) with short clusters of inclusions such as MgCO_(3) and FeCO_(3).Finally,the unsoundness problem of steel slag can be fundamentally solved when the carbonation temperature is higher than 90℃and the time is longer than 9 h.The volume expansion rate of asphalt mixture cured for 3 d(about 0.97%)is lower than 35%of the standard value(1.5%),and the expansion rate of 6 d(about 1.16%)tends to be stable and lower than 23%of the standard value,which achieves the purpose of long-term good stability of steel slag asphalt concrete.
作者
胡晨光
李恩硕
苏航
付佳伟
HU Chenguang;LI Enshuo;SU Hang;FU Jiawei(College of Materials Science and Engineering,North China University of Science and Technology,Tangshan 063210,China;Laboratory of Inorganic Material of Hebei Province,Tangshan 063210,China)
出处
《金属矿山》
CAS
北大核心
2022年第11期238-245,共8页
Metal Mine
基金
河北省高端钢铁冶金联合基金项目(编号:E2020209010)
唐山市科技计划项目(编号:19150225E)。
关键词
钢渣集料
碳酸化制度
沥青混合料体积稳定性
安定性
微观形貌
steel slag aggregate
carbonation system
volume stability of asphalt mixture
soundness
microstructure
