竹杆生物炭改性水泥土的三轴力学特性研究

doi:10.16552/j.cnki.issn1001-1625.2026.0041

摘要/Abstract

摘要：

为了探究竹杆生物炭对不同龄期下水泥土的改性效果，通过不固结不排水三轴试验，研究了竹杆生物炭改性水泥土（BBMCS）的偏应力-应变曲线、峰值偏应力、内摩擦角和黏聚力等力学特性。结果表明：竹杆生物炭可通过优化水泥土内部结构改善其应力-应变曲线形态，BBMCS试样的偏应力-应变曲线均呈软化型，表现为脆性破坏特征；在7和28 d养护龄期下，6%（质量分数）竹杆生物炭掺量的BBMCS试样力学性能最优，其峰值偏应力较未掺竹杆生物炭的对照组分别提升89%和81%；竹杆生物炭对BBMCS力学性能的增强作用主要源于黏聚力的提升，对内摩擦角无显著影响。基于试验数据，建立了不同龄期下竹杆生物炭掺量、围压与峰值偏应力的二次函数预测模型，模型预测值与实测值吻合良好。研究结果可为竹杆生物炭改性水泥土的工程应用提供基础。

关键词: 水泥土, 竹杆生物炭, 三轴试验, 力学特性, 峰值偏应力, 抗剪强度

Abstract:

To investigate the modification effect of bamboo stem biochar on cement-stabilized soil at different curing ages， this study examined the mechanical properties of bamboo stem biochar-modified cement-stabilized soil （BBMCS） specimens， including deviatoric stress-strain curves， peak deviatoric stress， internal friction angle， and cohesion， via unconsolidated-undrained （UU） triaxial tests. The results indicate that bamboo stem biochar improves the morphology of the stress-strain curves of cement-stabilized soil by optimizing its internal structure. The deviatoric stress-strain curves of all BBMCS specimens exhibit strain-softening behavior， characterized by brittle failure. At curing ages of 7 and 28 d， BBMCS specimens with a bamboo stem biochar content of 6% （by mass） demonstrate optimal mechanical properties， with their peak deviatoric stress increasing by 89% and 81%， respectively， compared to the control group without bamboo stem biochar. The enhancement of mechanical properties in BBMCS by bamboo stem biochar is primarily attributed to the improvement of cohesion， with no significant effect observed on the internal friction angle. Based on the experimental data， a quadratic prediction model relating bamboo stem biochar content， confining pressure， and peak deviatoric stress at different curing ages was established. The predicted values show good agreement with the measured values. These findings provide basis for the engineering application of BBMCS.

Key words: cement-stabilized soil, bamboo stem biochar, triaxial test, mechanical property, peak deviatoric stress, shear strength

中图分类号:

TU44

孔爱散, 洪雅璐, 叶敏辉, 吴鸿祥, 汤薇, 李娜, 王伟. 竹杆生物炭改性水泥土的三轴力学特性研究[J]. 硅酸盐通报, 2026, 45(5): 1603-1614.

KONG Aisan, HONG Yalu, YE Minhui, WU Hongxiang, TANG Wei, LI Na, WANG Wei. Triaxial Mechanical Properties of Bamboo Stem Biochar-Modified Cement-Stabilized Soil[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(5): 1603-1614.

图/表 17

图1 土样的粒径分布

Fig.1 Particle size distribution of soil

图2 原材料的XRD谱

Fig.2 XRD patterns of raw materials

图3 原材料的SEM照片

Fig.3 SEM images of raw materials

表1 水泥的主要氧化物组成

Table 1 Main oxide composition of cement

Component	CaO	SiO₂	Fe₂O₃	Al₂O₃	SO₃	MgO	Other
Mass fraction/%	50.20	18.50	12.50	8.90	4.60	3.40	1.90

表2 竹杆生物炭的主要氧化物组成

Table 2 Main oxide composition of bamboo stem biochar

Component	K₂O	CaO	SiO₂	Fe₂O₃	SO₃	P₂O₅	MnO	Other
Mass fraction/%	59.11	11.63	10.16	4.42	4.22	3.66	3.43	3.37

表3 不同竹杆生物炭掺量下试样的配合比设计与测试龄期

Table 3 Mix proportion design and test ages of specimens with different content of bamboo stem biochar

No.	Cement content/%	Bamboo stem biochar content/%	Moisture content/%	Confining pressure/kPa	Curing age/d
CS-7	5	0	18	100， 200， 300， 400	7
BBMCS-2-7	5	2	18	100， 200， 300， 400	7
BBMCS-4-7	5	4	18	100， 200， 300， 400	7
BBMCS-6-7	5	6	18	100， 200， 300， 400	7
BBMCS-8-7	5	8	18	100， 200， 300， 400	7
CS-28	5	0	18	100， 200， 300， 400	28
BBMCS-2-28	5	2	18	100， 200， 300， 400	28
BBMCS-4-28	5	4	18	100， 200， 300， 400	28
BBMCS-6-28	5	6	18	100， 200， 300， 400	28
BBMCS-8-28	5	8	18	100， 200， 300， 400	28

图4 BBMCS试样的制备流程

Fig.4 Flow chart of preparation of BBMCS specimens

图5 不同竹杆生物炭掺量、不同养护龄期下试样的偏应力-应变曲线

Fig.5 Deviatoric stress-strain curves of specimens with different bamboo stem biochar content and curing ages

图6 不同龄期下试样的峰值偏应力

Fig.6 Peak deviatoric stress of specimens at different ages

表4 不同竹杆生物炭掺量、不同围压下试样的峰值偏应力

Table 4 Peak deviatoric stress of specimens with different bamboo stem biochar content and confining pressures

No.	Peak deviatoric stress/kPa
No.	100 kPa	200 kPa	300 kPa	400 kPa
CS-7	1 309	1 396	1 877	1 988
BBMCS-2-7	1 498	1 759	1 996	2 429
BBMCS-4-7	1 672	1 995	2 385	2 490
BBMCS-6-7	2 180	2 987	3 154	3 232
BBMCS-8-7	1 946	2 316	2 432	2 854
CS-28	1 648	1 942	2 033	2 448
BBMCS-2-28	1 723	2 362	2 468	2 577
BBMCS-4-28	2 166	2 628	2 864	3 081
BBMCS-6-28	3 062	3 365	4 062	4 068
BBMCS-8-28	2 357	2 914	3 032	3 109

图7 不同龄期下试样的预测模型拟合图

Fig.7 Fitting diagrams of prediction model for specimens at different ages

图8 不同竹杆生物炭掺量、围压和龄期下试样峰值偏应力预测值与试验值对比图

Fig.8 Comparison diagrams of predicted and experimental values of peak deviatoric stress of specimens with different bamboo stem biochar content， confining pressures and ages

表5 预测模型系数A与龄期相关公式

Table 5 Correlation formula between prediction model coefficient A and age

Coefficient	Data for 7 d	Data for 28 d	Formulas related to curing ages（D： curing age）
A₁	-18.23	-27.67	A₁= -0.45D-15.08
A₂	256.95	362.59	A₂= 5.03D+221.74
A₃	701.93	840.06	A₃= 6.58D+655.89

表6 预测模型系数B与龄期加权平均值

Table 6 Predicted model coefficient B and weighted average of age

Coefficient	Data for 7 d	Data for 28 d	Weighted average of curing age
B₁	0	-0.01	-0.01
B₂	-0.05	0.04	0.02
B₃	4.47	6.26	5.90

图9 不同竹杆生物炭掺量、不同养护龄期下试样的莫尔-库仑强度包络线

Fig.9 Mohr-Coulomb strength envelopes of specimens with different bamboo stem biochar content and curing ages

图10 竹杆生物炭改性水泥土的微观机理图

Fig.10 Microscopic mechanism diagram of bamboo stem biochar modified cement-stabilized soil

表7 不同竹杆生物炭掺量、养护龄期下试样的抗剪强度

Table 7 Shear strength of specimens with different bamboo stem biochar content and curing ages

No.	Curing age/d	Angle of internal friction/（°）	Cohesion/kPa	Shear stress envelope curve
CS-7	7	34.73	256.70	τ=0.69σ+256.70
BBMCS-2-7	7	37.26	285.85	τ=0.76σ+285.85
BBMCS-4-7	7	36.40	355.09	τ=0.74σ+355.09
BBMCS-6-7	7	41.29	434.25	τ=0.87σ+434.25
BBMCS-8-7	7	36.33	419.90	τ=0.74σ+419.90
CS-28	28	34.21	364.03	τ=0.68σ+364.03
BBMCS-2-28	28	37.04	379.78	τ=0.75σ+379.28
BBMCS-4-28	28	37.15	477.60	τ=0.76σ+477.60
BBMCS-6-28	28	41.80	590.37	τ=0.89σ+590.37
BBMCS-8-28	28	34.89	569.90	τ=0.70σ+569.90

参考文献 30

[1]	ZHOU A Z， WANG H N， HUANG R D， et al. Enhancement-type graphene treated cement-soil for building foundation improvement： experimental and microscopic investigations［J］. Journal of Building Engineering， 2025， 114： 114251.
[2]	VAN ROIJEN E， MILLER S A， DAVIS S J. Building materials could store more than 16 billion tonnes of CO₂ annually［J］. Science， 2025， 387（6730）： 176-182.
[3]	CHEN Y Y， ZHAN B G， GUO B L， et al. Accelerated carbonation curing of biochar-cement mortar： effects of biochar pyrolysis temperatures on carbon sequestration， mechanical properties and microstructure［J］. Construction and Building Materials， 2024， 449： 138446.
[4]	LIN X Q， NGUYEN Q D， CASTEL A， et al. Self-healing efficiency of sustainable biochar-cement composites incorporating crystalline admixtures［J］. Construction and Building Materials， 2025， 458： 139542.
[5]	SOBUZ M H R， KHAN M H， KABBO M K I， et al. Assessment of mechanical properties with machine learning modeling and durability， and microstructural characteristics of a biochar-cement mortar composite［J］. Construction and Building Materials， 2024， 411： 134281.
[6]	LIU K N， FAN D Q， ZOU S， et al. Capacitance capacity of biochar-incorporated cementitious composite［J］. Resources， Conservation and Recycling， 2025， 218： 108223.
[7]	LIU W， TAN S L， QING L B， et al. Pozzolanic activity of biochar with high carbon content and its influence on comprehensive strength-emission performance of biochar-cement composite paste［J］. Construction and Building Materials， 2025， 478： 141427.
[8]	ZHAO Z H， EL-NAGGAR A， KAU J， et al. Biochar affects compressive strength of Portland cement composites： a meta-analysis［J］. Biochar， 2024， 6（1）： 21.
[9]	XU W J， ZHANG Y Y， SU Y L， et al. Using waste to improve the weak： recycled seashell as an ideal way to regulate the interfacial transition zone in biochar-cement composites［J］. Construction and Building Materials， 2024， 444： 137765.
[10]	KANG Z Y， ZHANG J R， LI N， et al. Utilization of biochar as a green additive in supersulfated cement： properties， mechanisms， and environmental impacts［J］. Construction and Building Materials， 2024， 445： 137923.
[11]	CHEN X Y， CHEN F M， YANG Q， et al. An environmental food packaging material part I： a case study of life-cycle assessment （LCA） for bamboo fiber environmental tableware［J］. Industrial Crops and Products， 2023， 194： 116279.
[12]	GIMBUN J， GUNASEKARAN P K， CHE J L， et al. Bamboo biochar addition enhanced cement mortar strength and CO₂ sequestration ability［J］. Physics and Chemistry of the Earth， Parts A/B/C， 2025， 141： 104155.
[13]	SUN H L， QING L B， LIU W， et al. Effects of bamboo waste biochar on fracture behavior of cementitious materials［J］. Theoretical and Applied Fracture Mechanics， 2025， 139： 105106.
[14]	SHAO Y L， HU A Q， JIANG Y C， et al. Preparation of biochars from different sources and study on their phosphorus adsorption properties［J］. Molecules， 2025， 30（12）： 2633.
[15]	REVATHI S， ALICE ELIZABETH TANIA D， ANCY SHADIN S， et al. Effect of zeolite and bamboo biochar as CO₂ absorbant in concrete［J］. Carbon Research， 2024， 3（1）： 43.
[16]	CHATURVEDI K， SINGHWANE A， DHANGAR M， et al. Bamboo for producing charcoal and biochar for versatile applications［J］. Biomass Conversion and Biorefinery， 2024， 14（14）： 15159-15185.
[17]	SU J Z， GUO Z L， ZHANG M Y， et al. Mn-modified bamboo biochar improves soil quality and immobilizes heavy metals in contaminated soils［J］. Environmental Technology & Innovation， 2024， 34： 103630.
[18]	LI L S， JIANG Y， CHEN T F， et al. Porous biochar-assisted aqueous carbonation of steel slag as an adsorptive crystallization modifier for value-added cement applications［J］. Cement and Concrete Composites， 2025， 159： 106002.
[19]	AWAD M， LIU Z Z， SKALICKY M， et al. Fractionation of heavy metals in multi-contaminated soil treated with biochar using the sequential extraction procedure［J］. Biomolecules， 2021， 11（3）： 448.
[20]	中华人民共和国住房和城乡建设部. 土工试验方法标准：［S］. 北京：中国计划出版社， 2019.
	Ministry of Housing and Urban-Rural Development of the People’s Republic of China. Standard for soil test methods：［S］. Beijing： China Planning Press， 2019 （in Chinese）.
[21]	中华人民共和国交通运输部. 公路土工试验规程：［S］. 北京：人民交通出版社， 2020.
	Ministry of Transport of the People’s Republic of China. Test methods of soils for highway engineering：［S］. Beijing： China Communications Press， 2020 （in Chinese）.
[22]	中华人民共和国交通运输部. 公路工程无机结合料稳定材料试验规程：［S］. 北京：人民交通出版社， 2024.
	Ministry of Transport of the People’s Republic of China. Test methods of materials stabilized with inorganic binders for highway engineering：［S］. Beijing： China Communications Press， 2024 （in Chinese）.
[23]	LIN W L， LIU A， MAO W W， et al. Acoustic emission characteristics of a dry sandy soil subjected to drained triaxial compression［J］. Acta Geotechnica， 2020， 15（9）： 2493-2506.
[24]	JIANG P， HU X C， WANG W， et al. Mechanical properties and energy dissipation of fiber-modified iron tailings under triaxial stress［J］. International Journal of Geomechanics， 2024， 24（12）： 06024022.
[25]	ZHANG Q， CHEN Y， JI J R， et al. Influence of biochar addition on the strength characteristics of red clay［J］. International Journal of Geomechanics， 2025， 25（9）： 04025192.
[26]	YANG Y Y， SUN L， LI P， et al. From agricultural waste to geotechnical application： investigation of apple tree biochar for loess reinforcement［J］. Powder Technology， 2025， 466： 121454.
[27]	LIU W， LI K N， XU S L. Utilizing bamboo biochar in cement mortar as a bio-modifier to improve the compressive strength and crack-resistance fracture ability［J］. Construction and Building Materials， 2022， 327： 126917.
[28]	LING Y F， WU X H， TAN K H， et al. Effect of biochar dosage and fineness on the mechanical properties and durability of concrete［J］. Materials， 2023， 16（7）： 2809.
[29]	ALFEI S， PANDOLI O G. Bamboo-based biochar： a still too little-studied black gold and its current applications［J］. Journal of Xenobiotics， 2024， 14（1）： 416-451.
[30]	XIAO S， LI Y C， XU C X， et al. The influence of biochar addition on the mechanical performance， hydration mechanism， and carbonation capacity of Super Sulfated Cement［J］. Construction and Building Materials， 2025， 463： 140073.