纳米材料改性再生骨料混凝土断裂性能
作者:
作者单位:

福州大学 土木工程学院,福建 福州 350116

作者简介:

罗素蓉(1963—),女,福建尤溪人,福州大学教授,硕士生导师,学士.E-mail:lsr@fzu.edu.cn

通讯作者:

罗素蓉(1963—),女,福建尤溪人,福州大学教授,硕士生导师,学士.E-mail:lsr@fzu.edu.cn

中图分类号:

TU528.041

基金项目:

国家自然科学基金资助项目(52078139)


Fracture Performance of Recycled Aggregate Concrete Modified by Nanomaterials
Author:
Affiliation:

College of Civil Engineering, Fuzhou University, Fuzhou 350116,China

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    摘要:

    将纳米SiO2(纳米硅溶胶和纳米SiO2粉末)与纳米CaCO3粉末加入再生骨料混凝土(RAC)中,制备得到纳米材料改性RAC.通过三点弯曲梁试验与传统电测法测试其断裂性能.结果表明:适当掺量的纳米SiO2和纳米CaCO3粉末能够有效提高RAC的28 d抗压强度与劈裂抗拉强度;分别掺入1.0%纳米硅溶胶、0.5%纳米SiO2粉末和2.0%纳米CaCO3粉末对RAC双K断裂参数和断裂能的提升效果最佳;相较普通混凝土,纳米材料改性RAC的断裂面出现更多贯通再生骨料的裂缝;纳米材料能够促进生成致密程度高的水化产物,减少混凝土界面过渡区内部的孔隙数量.

    Abstract:

    Recycled aggregate concrete (RAC) was modified by adding nano-SiO2 (nano-silica sol and nano-SiO2 powder)and nano-CaCO3 powder to study the fracture performance. The fracture property of RAC modified by nano-materials was tested by three-point bending beam method and traditional electrical measurement. The results show that the 28 d compressive strength and splitting tensile strength of RAC can be effectively improved by adding proper amount of nano-SiO2 and nano-CaCO3. Adding 1.0% nano-silica sol,0.5% nano-SiO2 powder and 2.0% nano-CaCO3 powder respectively has the most effective on the improvement of double-K fracture parameters and fracture energy. After the addition of nanomaterials, more cracks pass through the recycled aggregate than that for ordinary concrete; nanomaterials promote production of higher density hydrate and reduction of the number of internal pore in interface transition zone.

    表 5 纳米压痕试验中各相的压痕杨氏模量值Table 5 Young′s modulus value of phase from nanoindentation[28-31]
    表 2 粗骨料的物理性能Table 2 Physical properties of coarse aggregates
    表 3 纳米材料的物理性能Table 3 Physical properties of nano-materials
    表 4 混凝土配合比及基本力学性能Table 4 Mix proportions and mechanical properties of concretes
    表 1 胶凝材料的化学组成Table 1 Chemical compositions of cementitious materials
    图1 三点弯曲梁试验简图Fig.1 Sketch of three-point bending beam experiment (size:mm)
    图2 应变片布置图Fig.2 Layout of strain gauge (size:mm)
    图3 纳米压痕11×11和21×11点阵示意图Fig.3 Schematic of nano indentation 11×11 and 21×11 lattice(size:μm)
    图4 RAC100 组试件的P-ε、P-δ和P-CMOD curve曲线Fig.4 P-ε,P-δ,P-CMOD curve of RAC100 specimens
    图5 试件预制裂缝上方断裂面破坏形态Fig.5 Failure forms above the crack of specimens
    图6 RAC试件典型界面过渡区的压痕点阵杨氏模量分布云图Fig.6 Distribution cloudy map of typical interface indentation lattice Youngs modulus of RAC specimens
    图7 掺入不同纳米材料的RAC界面过渡区的模量概率分布Fig.7 Probability distribution of modulus in the interface transition region of RAC with different nano materials
    表 7 不同纳米材料掺量下各界面的界面特征参数Table 7 Characteristic parameters of various interface with different nano-material content
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罗素蓉,林倩,李炜源,王德辉.纳米材料改性再生骨料混凝土断裂性能[J].建筑材料学报,2022,25(11):1151-1159

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  • 收稿日期:2022-04-29
  • 最后修改日期:2022-07-03
  • 在线发布日期: 2022-11-30
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