纤维丝和网加筋泡沫轻质土力学特性和抗冻性

陈成华; 黄志超; 黄俊杰; 杨晨

doi:10.3969/j.issn.0258-2724.20210160

纤维丝和网加筋泡沫轻质土力学特性和抗冻性

doi: 10.3969/j.issn.0258-2724.20210160

陈成华^1,,
黄志超²,
黄俊杰^{2, 3, ,},
杨晨²

1.
广西路建工程集团有限公司，广西南宁 530001
2.
西南交通大学土木工程学院，四川成都 610031
3.
西南交通大学高速铁路线路工程教育部重点实验室，四川成都 610031

基金项目: 国家自然科学基金（52078434）；四川省科技计划（重大前沿）（2016JY0005）

详细信息

作者简介:
陈成华（1985—），男，高级工程师，研究方向为道路与桥涵技术研究与施工管理，E-mail：306397834@qq.com

通讯作者:
黄俊杰（1984—），男，副教授，博士，硕士生导师，研究方向为铁路、公路路基工程，E-mail：jjhuang_swjtu@126.com

中图分类号: U213.1
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- 被引次数: 0
出版历程
- 收稿日期: 2021-03-02
- 修回日期: 2021-06-25
- 网络出版日期: 2022-11-29
- 刊出日期: 2021-07-06

Mechanical Property and Frost Resistance Analysis of Foamed Lightweight Soil with Fiber Filament and Mesh Reinforcement

1.
Guangxi Road Construction Engineering Group Co., Ltd., Nanning 530001 China
2.
School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China
3.
Key Laboratory of High-Speed Railway Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China

摘要

摘要:
为分析短纤维丝和纤维网加筋对泡沫轻质土力学性能和抗冻性的影响，开展了一系列的无侧限抗压强度试验、抗折强度试验、动三轴试验和冻融循环试验. 试验结果表明：对提高抗压强度而言，设计湿密度为700 kg/m³的泡沫轻质土掺入短纤维丝的最优长度和掺量分别为6 mm和0.4%；采用长度6 mm和掺量0.4%的短纤维丝对设计湿密度在400～1 000 kg/m³的泡沫轻质土进行加筋后，泡沫轻质土抗压强度、抗折强度和动应力阈值得到了显著地提高，最小提高量分别为35.3%、31.4%和53.4%；采用长度6 mm和掺量0.6%的短纤维丝对泡沫轻质土进行加筋后，设计湿密度分别为400、700、1 000 kg/m³的泡沫轻质土抗冻融循环次数分别由5、25、125次提高至10、50次和超过150次，泡沫轻质土抗冻性得到了显著地提高；相对于提高泡沫轻质土抗折强度而言，纤维网0.4%短纤维丝复合加筋的效果最好，单一纤维网加筋方式次之，单一短纤维丝加筋方式最差；短纤维丝、纤维网或两者复合加筋均显著地增加泡沫轻质土的韧性.
- 泡沫轻质土 /
- 短纤维丝 /
- 纤维网 /
- 抗压强度 /
- 抗折强度 /
- 抗冻性
Abstract:
In order to analyze the influence of the short fiber filaments and fiber mesh reinforcement on the mechanical property and frost resistance of foamed lightweight soil, a series of tests including unconfined compression tests, flexural strength tests, dynamic triaxial tests, and freeze-thaw cycle tests were performed. The results showed that to improve the compressive strength of the foamed lightweight soil, the optimal length and content of the short glass fiber mixed into the foamed lightweight soil with a design wet density of 700 kg/m³ are 6 mm and 0.4%, respectively. After the foamed lightweight soil with the designed wet density ranging from 400 to 1 000 kg/m³ was reinforced using short glass fibers with length of 6 mm and content of 0.6%, their compressive strength, flexural strength, and dynamic stress threshold were significantly improved, with the minimum increases being 35.3%, 31.4% and 53.4%, respectively. When the foamed lightweight soil had been reinforced with short glass fibers with length of 6 mm and content of 0.6%, the freezing-thawing durability of the foamed lightweight soil with design wet densities of 400, 700 and 1 000 kg/m³ increased from 5 cycles to 10 cycles, 25 cycles to 50 cycles, and 125 cycles to more than 150 cycles, respectively. This indicates that the frost resistance of the foamed lightweight soil was significantly improved. To improve the flexural strength of the foamed lightweight soil, the effect of the reinforcement by the glass fiber mesh combined with short fiber filaments (0.4% in weight) was the best, the effect of the single glass fiber mesh reinforcement was the second, and the effect of the single glass fiber filament reinforcement was the worst. Additionally, the toughness of the foamed lightweight soil can be improved significantly by short glass fiber filament reinforcement, glass fiber mesh reinforcement, or glass fiber mesh combined with short glass fiber filament reinforcement.
- foamed lightweight soil /
- short fiber filament /
- fiber mesh /
- compressive strength /
- flexural strength /
- frost resistance

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图 1 玻璃纤维网

Figure 1. Glass fiber mesh

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图 2 立方体试样制作过程

Figure 2. Making process of cubic specimen

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图 3 加入纤维网后长方体试块状态

Figure 3. Status of cuboid test blocks with fiber mesh

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图 4 弯折试验示意

Figure 4. Schematic of bending test

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图 5 短纤维丝长度对抗压强度的影响规律

Figure 5. Influence of the short glass fiber length on the compressive strength

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图 6 泡沫轻质土抗压强度和抗折强度随湿密度的变化规律

Figure 6. Variation of the flexural strength and compressive strength of the foamed lightweight soil with wet density

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图 7 泡沫轻质土动应力阈值随湿密度的变化规律

Figure 7. Variation of the dynamic stress threshold of the foamed lightweight soil with wet density

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图 8 泡沫轻质土质量和抗压强度损失率与冻融循环的关系

Figure 8. Relations of the mass and compressive strength loss rates of foamed lightweight soil with the freeze-thaw cycles

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图 9 经设定冻融循环次数后有、无加筋的试样形态

Figure 9. Morphological photos of specimens with and without glass fiber reinforcement after a fixed number of freeze-thaw cycles

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图 10 短纤维丝加筋试块裂缝之间纤维丝呈“跨接状态”

Figure 10. Bridging state of the glass fiber between cracks in the short glass fiber reinforced specimen

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表 1 P·O42.5普通硅酸盐水泥的主要化学成分和物理性能

Table 1. Main chemical component and physical properties of Ordinary Portland Cement 42.5

化学指标百分比/%									物理指标
SiO₂	Fe₂O₃	Al₂O₃	CaO	MgO	SO₃	K₂O	Na₂O	烧失量	细度/（m²·kg⁻¹）	比重/（kN·m⁻³）
22.02	2.65	6.19	58.99	2.53	2.67	0.58	0.36	3.08	391.00	3.07

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表 2 复合型发泡剂的主要物理性能

Table 2. Main physical performances of the compound foaming agent

PH 值	挥发性有机化合物/（g·L⁻¹）	密度/（kg·L⁻¹）	游离甲醛/（g·kg）	发泡倍数	苯/（g·kg⁻¹）	甲苯十二苯/（g·kg⁻¹）
7.1	15	1.13	0.3	≥50	0	0

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表 3 耐碱玻璃纤维主要物理力学参数

Table 3. Main physical and mechanical parameters of the alkali-resistant glass fiber

直径/ μm	线密度/ dtex	抗拉强度/MPa	断裂伸长率/%	拉伸模量/ GPa
15	78	2 000	2.5	75

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表 4 未加筋泡沫轻质土配比

Table 4. Mixing proportions of the foamed lightweight soil without glass fibers

组序	设计湿密度/ （kg·m⁻³）	水泥/kg	水/kg	水灰比	泡沫/kg
D4	400	217.63	163.23	0.75	19.15
D5	500	283.70	198.59	0.70	17.73
D6	600	353.72	229.92	0.65	16.37
D7	700	428.07	256.84	0.60	15.09
D8	800	507.17	278.94	0.55	13.90
D9	900	580.02	307.41	0.53	12.59
D10	1000	659.08	329.54	0.50	11.17

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表 5 不同加筋方式的泡沫轻质土抗折强度

Table 5. Flexural strength of the foamed lightweight soil with different patterns of reinforcement MPa

设计湿密度/ （kg·m⁻³）	未加筋	0.4% 短纤维	纤维网	纤维网 + 0.4% 短纤维丝
500	0.321	0.529	1.028	1.453
700	0.781	1.386	2.359	2.951
900	1.278	2.084	4.551	5.159

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