硫酸铝对喷射混凝土钙溶蚀过程的影响及作用机理
作者:
作者单位:

西安建筑科技大学 材料科学与工程学院,陕西 西安 710055

作者简介:

张紫薇(1995—),女,陕西西安人,西安建筑科技大学博士生. E-mail:zziwei@xauat.edu.cn

通讯作者:

李国新(1975—),男,湖北汉川人,西安建筑科技大学教授,博士生导师,博士. E-mail:liguoxin@xauat.edu.cn

中图分类号:

TU528.53

基金项目:

陕西省交通运输厅科研项目(19-19K)


Influence of Aluminum Sulfate on Calcium Leaching Process of Shotcrete and Its Mechanism
Author:
Affiliation:

College of Materials Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China

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    摘要:

    为研究硫酸铝(AS)对喷射混凝土钙溶蚀过程的影响及作用机理,分析了含AS水泥砂浆试样在6 mol/L氯化铵溶液中的性能变化.结果表明:AS掺量对水泥砂浆试件的钙溶蚀过程有显著影响,掺2%AS有利于延缓砂浆试样在加速溶蚀过程中的性能退化;钙溶蚀过程导致水泥水化产物中的氢氧化钙(CH)溶解,水化硅酸钙(C-S-H)凝胶和钙矾石(AFt)脱钙,生成易溶的氯化钙,加速水泥石解体;加入AS会改变水泥水化产物的组成与结构,以及水泥石的微观结构,进而影响喷射混凝土的钙溶蚀过程.

    Abstract:

    By investigating the performance changes of mortar samples containing aluminum sulfate(AS) in 6 mol/L NH4Cl solution, the influence and mechanism of action of aluminum sulfate on the calcium leaching process of shotcrete were analyzed. The results show that the use level of AS has a significant impact on the calcium leaching process of mortar samples. The addition of 2% AS is beneficial in delaying the performance degradation of mortar samples during accelerated leaching. The leaching process leads to the dissolution of calcium hydroxide in the cement hydration products, the decalcification of calcium silicate hydrate gel and ettringite, and the formation of soluble CaCl2, which accelerates the disintegration of cement stone. The addition of AS alters the composition and structure of cement hydration products, as well as the microstructure of cement stone, thereby influencing the calcium leaching process of shotcrete.

    图1 线扫描和面扫描的取样和扫描方式示意图Fig.1 Sampling and scanning method diagram of line scan and area scan
    图2 水泥砂浆试样的抗压强度Fig.2 Compressive strength of cement mortar samples
    图3 水泥砂浆试样的质量变化率Fig.3 Mass change rate of cement mortar samples
    图4 水泥砂浆试样的吸水率Fig.4 Water absorption of cement mortar samples
    图5 水泥砂浆试样的溶蚀深度Fig.5 Erosion depth of cement mortar samples
    图6 水泥净浆试样溶蚀前水泥水化产物的XRD图谱Fig.6 XRD patterns of cement hydration products of cement paste samples before leaching
    图7 水泥净浆试样溶蚀前水泥水化产物的TG-DTG曲线Fig.7 TG-DTG curves of cement hydration products of cement paste samples before leaching
    图8 水泥净浆试样溶蚀7 d后的元素线扫描Fig.8 Element line scan results of cement paste samples after leaching for 7 d
    图9 水泥净浆试样溶蚀前水泥水化产物的微观结构Fig.9 Microstructure of cement hydration products of cement paste samples before leaching
    图10 水泥净浆试样溶蚀28 d后的元素面扫描结果Fig.10 Element area scan results of cement paste samples after leaching for 28 d
    表 1 水泥的化学组成Table 1 Chemical composition(by mass)of cement
    表 2 试验配合比Table 2 Mix proportions for test Unit:g
    表 3 水泥净浆试样的凝结时间Table 3 Setting times of cement paste samples
    表 4 水泥净浆试样溶蚀前水泥水化产物含量及结合水量Table 4 Content(by mass) of hydration product and bound water of cement paste samples before leaching
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张紫薇,牛梦蝶,李国新.硫酸铝对喷射混凝土钙溶蚀过程的影响及作用机理[J].建筑材料学报,2025,28(3):244-251

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  • 收稿日期:2024-03-26
  • 最后修改日期:2024-06-14
  • 在线发布日期: 2025-04-06
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