摘要
按传统矿质混合料设计掺磷石膏道路基层材料难以大规模消纳磷石膏,为实现磷石膏在道路基层材料中大规模利用,通过骨料替代法进行高掺量磷石膏道路基层材料配比设计,确定适宜的碎石比(5~10 mm粒级与10~25 mm粒级质量比39∶61)后以不同掺量替代磷石膏基胶凝材料体系,再击实然后得出最佳含水率及最大干密度。通过对设计好的配比进行性能试验筛选,得出适宜配比为P85S60,养护28 d的试件抗压强度最大达5.39 MPa,体积变化率较低,且养护7 d后试件的体积增长稳定,体积变化率最终维持在0.5%左右,有利于现场道路施工应用。所有配比浸出氟、磷均满足《污水综合排放标准》(GB 8978—1996)一级限值,相较于常规水泥稳定碎石材料,该道路基层材料浸出液的酸碱性不会额外增加不利影响。通过XRD和SEM分析可知,胶凝材料水化产生的钙矾石和水化硅酸钙包裹在未反应的二水石膏周围,另外针棒状钙矾石和水化硅酸钙填充微小孔隙,使得试件整体结构密实、强度增加、体积稳定性增强。
The phosphogypsum road base material designed by traditional mineral mixture is difficult to meet the demand of large-scale consumption of phosphogypsum.In order to realize the large-scale utilization of phosphogypsum in road base ma-terial,the mix ratio design of high-volume phosphogypsum road base material was explored with aggregate substitution method to determine the propriate graded gravel ratio(mass ratio of 5~10 mm and 10~25 mm fraction of 39∶61).As a substitute for the phosphogypsum-based cementitious material system,the aggregate with different dosages were employed to reach the opti-mum water content and maximum dry density by compaction.The performance test was carried out with the designed mix ratio to screen the propriate ratio as P85S60.For P85S60,the 28 d compressive strength reached 5.39 MPa,but the volume change rate was low,and the volume growth became stable after 7 days with the ultimate volume change rate as about 0.5%,which was conducive to the application of on-site road construction.The fluorine and phosphorus content in the leaching of all ratios meets the first-level limit of Integrated Wastewater Discharge Standard(GB 8978—1996),and the pH of the leaching solution would not increase additional adverse effects compared with conventional cement stabilized crushed stone materials.According to re-sults from XRD and SEM,it can be found that ettringite and hydrated calcium silicate produced by the hydration of the cemen-titious material wrapped around the unreacted dihydrate gypsum.In addition,needle-shaped ettringite and hydrated calcium sil-icate fill tiny pores,making the overall structure dense to form big strength and volume stability.
作者
黄绪泉
吴钦楠
赵小蓉
董江峰
李茜
HUANG Xuquan;WU Qinnan;ZHAO Xiaorong;DONG Jiangfeng;LI Qian(Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education,Yichang 443002,China;College of Hydraulic&Environmental Engineering,China Three Gorges University,Yichang 443002,China;Yichang Key Laboratory of Solid Waste Disposal and Resource Utilization,Yichang 443002,China;Hubei Province Enterprise-college Cooperation Innovation Center for Comprehensive Utilization of Phosphogypsum,Yichang 443002,China;Central and Southern China Municipal Engineering Design&Research Institute Co.,Ltd.,Wuhan 430010,China)
出处
《金属矿山》
CAS
北大核心
2024年第3期296-302,共7页
Metal Mine
基金
三峡库区生态环境教育部工程研究中心开放基金课题项目(编号:KF2022-11,KF-2023-07)
宜昌市自然科学研究项目(编号:A23-2-020)。
关键词
道路基层材料
配比设计
性能试验
磷石膏
抗压强度
体积变化率
road base material
mix ratio design
performance test
phosphogypsum
compressive strength
volume change rate
