吉林大学学报(工学版) ›› 2021, Vol. 51 ›› Issue (1): 252-258.doi: 10.13229/j.cnki.jdxbgxb20200242

• 交通运输工程·土木工程 • 上一篇    

脱硫石膏水泥稳定碎石减缩与增强行为机制

陆青清1,2()   

  1. 1.同济大学 道路与交通工程教育部重点试验室,上海 201804
    2.上海公路桥梁(集团)有限公司,上海 200433
  • 收稿日期:2020-04-08 出版日期:2021-01-01 发布日期:2021-01-20
  • 作者简介:陆青清(1984-),男,高级工程师,博士. 研究方向:路面工程材料与施工工艺.E-mail:lqq6677@163.com
  • 基金资助:
    国家自然科学基金项目(51708342)

Strength enhancement and shrinkage reduction mechanism of desulfurized gypsum cement stabilized aggregates

Qing-qing LU1,2()   

  1. 1.Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Tongji University,Shanghai 201804,China
    2.Shanghai Road and Bridge(Group) Co. Ltd. ,Shanghai 200433,China
  • Received:2020-04-08 Online:2021-01-01 Published:2021-01-20

摘要:

采用抗压强度、抗折强度、干缩温缩、扫描电镜、X射线衍射试验,评价脱硫石膏矿渣水泥稳定碎石的变形特性与强度特征。结果表明:在胶凝体系中,脱硫石膏置换出铝酸钙结晶过程中消耗的氢氧化钙,促进火山灰反应,提高胶凝强度;将铝酸钙晶体转化为钙矾石,实现体积微膨胀,减小收缩变形;脱硫石膏、矿渣存在较佳的掺比例,对于中粒式骨架密实型混合料,矿渣掺量不低于水泥剂量,脱硫石膏掺量在3.0%~6.0%范围内。

关键词: 脱硫石膏, 矿渣, 水泥稳定碎石, 收缩特性, 强度特征

Abstract:

Desulfurization gypsum is a kind of industrial wastes. When mixed with fly ash and slag, it can enhance the reaction efficiency, increase the cohesiveness of cementation systems and reduce the amount of cement. Furthermore, gypsum cement gel material has a slight expansion function, which contributes to improving the compactness of materials, delaying the shrinkage cracking. Currently, gypsum is just used as roadbed filler, which can not fully play its performance. Based on this background, in this paper, the gypsum cement stabilized aggregate formation mechanism and its engineering application were investigated to identify the mechanism of “excitation”, “enhancement” and “reduction” of shrinkage. Referring to the cement performance test, the effects of gypsum on the retarding effect, strength characteristics and stability of the composite gel system were analyzed. Scanning electron microscope images and X-ray diffraction patterns were applied to reveal the mechanism of the effect of gypsum on the chemical reaction of composite gel system. The results reveal the volumetric micro-swelling and the three-stage development of the composite gel system. The feature of volume swell is derived from the crystallization of gypsum and the formation of ettringite. The three-stage strength development characteristics are derived from the excitation of desulfurization gypsum to active ingredients in the slag, crystallization pressure generated by the ettringite formation, and gypsum filling. For medium-particle composite stabilized aggregates, the proportion of slag should not be lower than the proportion of cement incorporation and the proportion of gypsum should not be less than 3.0%, not be more than 6.0%.

Key words: flue-gas desulfurization gypsum, blast furnace slag, cement stabilized aggregate, shrinkage characteristics, strength characteristics

中图分类号: 

  • TQ172

表1

原材料化学成分(质量分数) (%)"

名称SiO2Al2O3Fe2O3CaOMgOSO3其他
脱硫石膏3.14.26.128.19.743.65.2
矿渣32.814.81.137.88.50.74.3
水泥26.59.14.947.43.31.07.8

表2

脱硫石膏-水泥-矿渣胶砂配比"

各类材料质量/g脱硫石膏掺配比/%
水泥矿渣脱硫石膏
225225135000
2252251327.522.55
22522513054510
22522512609020
225225121513530
225225121522550
225225108027060
2252251012.5337.575
22522594540590
225225900450100
225225787.5562.5125
225225675675150
225225562.5787.5175
225225450900200

图1

脱硫石膏掺量对干缩应变影响"

图2

硫石膏掺量对累计温缩应变、平均温缩系数影响"

图3

脱硫石膏掺量对凝胶材料的抗压强度影响"

图4

脱硫石膏掺量对凝胶材料的抗折强度影响"

图5

脱硫石膏掺量对稳定碎石7 d和28 d抗压强度影响"

图6

不同脱硫石膏掺量下凝胶的SEM图像"

图7

不同脱硫石膏掺量的XRD衍射图"

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