Evolution of Pore Structure in Silica Fume Modified Coal Gangue Concrete under Low Temperature Environment

Abstract

Abstract: To solve the problem of short service life of coal gangue concrete at low temperature, the freeze-thaw cycle test, and nuclear magnetic resonance test were carried out on the coal gangue concrete specimens with different water-binder ratios (0.45,0.35,0.25), and silica fume (SF) content (0%, 5%, 10%, 15%, mass fraction) by adding SF. The mass loss rate, relative dynamic elastic modulus, and pore structure distribution of each group of specimens were tested, and the influence of pore structure evolution on the frost resistance durability of coal gangue concrete under freeze-thaw cycle was analyzed. The results show that after 50 times freeze-thaw cycles, the mass loss rate of coal gangue concrete changes from negative to positive, and the specimen with water-binder ratio of 0.25 gradually produces alkali-aggregate reaction. After 75 times freeze-thaw cycles, SF increases the relative dynamic elastic modulus by 13.60%~62.98%. The addition of SF can improve the mass loss rate and relative dynamic elastic modulus, and inhibit alkali-aggregate failure of coal gangue concrete. During the freeze-thaw process, gel pores (r≤0.01 μm) and fine capillary pores (0.01 μm＜r≤0.05 μm) are gradually transformed into large capillary pores (0.1 μm＜r≤10 μm). The number of large capillary pores is the main factor that determines the occurrence of freeze-thaw damage. The addition of SF slows down the increase rate of large capillary pores and improves the anti-freezing durability of coal gangue coarse aggregate. The freeze-thaw damage model based on macro-scale (relative dynamic elastic modulus) and micro-scale (different pore size integral area) is established. The micro-scale freeze-thaw damage model considering different pore size is also suitable for coal gangue concrete. When the water cement ratio is 0.35 and the SF content is 10%, the coal gangue concrete can serve for 4 714 d in low temperature environment in the northwest region.

Key words: low temperature environment, coal gangue concrete, silica fume modification, nuclear magnetic resonance, pore structure, damage model

CLC Number:

U414

LI Shaoping, SHAN Junwei, LIU Xiaoqin, GUO Meirong, ZHANG Xuening, JING Hongjun, GAO Meng, CHEN Shaojie. Evolution of Pore Structure in Silica Fume Modified Coal Gangue Concrete under Low Temperature Environment[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(9): 3262-3272.

References

[1] SHI Z S, ZHAO H W, LIANG B, et al. Simulation test study on filling flow law of gangue slurry in goaf[J]. Scientific Reports, 2023, 13: 19117.
[2] DU T, WANG D M, BAI Y J, et al. Optimizing the formulation of coal gangue planting substrate using wastes: the sustainability of coal mine ecological restoration[J]. Ecological Engineering, 2020, 143: 105669.
[3] SUN J B, LIU S K, MA Z G, et al. Mechanical properties prediction of lightweight coal gangue shotcrete[J]. Journal of Building Engineering, 2023, 80: 108088.
[4] 关虓, 陈霁溪, 朱梦宇, 等. 微波活化煤矸石对水泥基材料的性能影响[J]. 材料导报, 2023, 37(4): 95-101.
GUAN X, CHEN J X, ZHU M Y, et al. Effect of microwave activated coal gangue on properties of cement-based materials[J]. Materials Reports, 2023, 37(4): 95-101 (in Chinese).
[5] 邱继生, 朱梦宇, 周云仙, 等. 粉煤灰对煤矸石混凝土界面过渡区的改性效应[J]. 材料导报, 2023, 37(2): 75-81.
QIU J S, ZHU M Y, ZHOU Y X, et al. Modification effect of fly ash on interfacial transition zone of coal gangue concrete[J]. Materials Reports, 2023, 37(2): 75-81 (in Chinese).
[6] LI M, LI A L, ZHANG J X, et al. Effects of particle sizes on compressive deformation and particle breakage of gangue used for coal mine goaf backfill[J]. Powder Technology, 2020, 360: 493-502.
[7] 田得龙. 协庄煤矿煤矸石回填治理塌陷区的环境可行性[J]. 煤炭技术, 2020, 39(4): 55-57.
TIAN D L. Environmental feasibility of coal gangue backfilling in subsidence area of Xiezhuang coal mine[J]. Coal Technology, 2020, 39(4): 55-57 (in Chinese).
[8] 冉德钦, 安斌, 李轶然, 等. 基于多孔介质煤矸石路基汞元素的扩散规律研究[J]. 材料导报, 2020, 34(增刊1): 255-257+267.
RAN D Q, AN B, LI Y R, et al. Study on diffusion law of mercury in coal gangue subgrade based on porous medium[J]. Materials Reports, 2020, 34(supplement 1): 255-257+267 (in Chinese).
[9] XU Y H, WU H J, DONG Z F, et al. Life cycle energy use efficiency and greenhouse gas emissions of circulating fluidized bed coal-fired plant with coal gangue and coal co-combustion[J]. Environment, Development and Sustainability, 2023: 1-23.
[10] 李贞, 王俊章, 申丽明, 等. 煤矸石物化成分对其资源化利用的影响[J]. 洁净煤技术, 2020, 26(6): 34-44.
LI Z, WANG J Z, SHEN L M, et al. Influence of the physical and chemical composition of coal gangue on its resource utilization[J]. Clean Coal Technology, 2020, 26(6): 34-44 (in Chinese).
[11] LI Y F, LIU S H, GUAN X M. Multitechnique investigation of concrete with coal gangue[J]. Construction and Building Materials, 2021, 301(1): 124114.
[12] 白国良, 刘瀚卿, 刘辉, 等. 煤矸石理化特性与煤矸石混凝土力学性能研究[J]. 建筑结构学报, 2023, 44(10): 243-254.
BAI G L, LIU H Q, LIU H, et al. Study on physicochemical properties of coal gangue and mechanical properties of coal gangue concrete[J]. Journal of Building Structures, 2023, 44(10): 243-254 (in Chinese).
[13] KARIMAEI M, DABBAGHI F, SADEGHI-NIK A, et al. Mechanical performance of green concrete produced with untreated coal waste aggregates[J]. Construction and Building Materials, 2020, 233: 117264.
[14] 郑传磊, 赵亚娣, 侯玉飞, 等. 冻融环境下再生粗骨料对聚丙烯纤维增强自密实混凝土轴心抗压力学性能的影响[J]. 材料科学与工程学报, 2023, 41(4): 672-680+567.
ZHENG C L, ZHAO Y D, HOU Y F, et al. Influence of recycled coarse aggregate on the axial compression resistance of PPF-SCC under freeze-thaw environment[J]. Journal of Materials Science and Engineering, 2023, 41(4): 672-680+567 (in Chinese).
[15] 邱继生, 潘杜, 关虓, 等. 冻融环境下煤矸石混凝土损伤演化规律研究[J]. 西安建筑科技大学学报(自然科学版), 2017, 49(5): 654-658.
QIU J S, PAN D, GUAN X, et al. Study on damage evolution law of coal gangue concrete amidst the freezing-thawing environment[J]. Journal of Xi'an University of Architecture & Technology (Natural Science Edition), 2017, 49(5): 654-658 (in Chinese).
[16] HUANG M, DUAN J M, WANG J K. Research on basic mechanical properties and fracture damage of coal gangue concrete subjected to freeze-thaw cycles[J]. Advances in Materials Science and Engineering, 2021, 2021: 6701628.
[17] ZHAO H, WANG S F, WANG R, et al. Utilization of raw coal gangue as coarse aggregates in pavement concrete[J]. Construction and Building Materials, 2023, 378(8): 131062.
[18] HUO Y L, HUANG J G, LU D, et al. Durability of alkali-activated slag concrete incorporating silica fume and rice husk ash[J]. Journal of Building Engineering, 2023, 78: 107637.
[19] MYADARABOINA H, LAW D, PATANIKUNI I. Very high volume fly ash concrete utilising microash and hydrated lime, with silica fume[J]. Advances in Cement Research, 2022, 34(9): 388-398.
[20] HAN X, FENG J J, WANG B M. Relationship between fractal feature and compressive strength of fly ash-cement composite cementitious materials[J]. Cement and Concrete Composites, 2023, 139: 105052.
[21] JI X, CHAN S Y N, FENG N. Fractal model for simulating the space-filling process of cement hydrates and fractal dimensions of pore structure of cement-based materials[J]. Cement and Concrete Research, 1997, 27(11): 1691-1699.
[22] PFEIFER P, AVNIR D. Chemistry in noninteger dimensions between two and three. I. Fractal theory of heterogeneous surfaces[J]. The Journal of Chemical Physics, 1983, 79(7): 3558-3565.
[23] NIU D, LI D, FU Q. A 3D-IFU model for characterising the pore structure of hybrid fibre-reinforced concrete[J]. Materials & Design, 2020, 188: 108473.
[24] 李温, 王海龙, 张佳豪, 等. 胶粉煤矸石混凝土力学特性及微观结构试验研究[J]. 排灌机械工程学报, 2023, 41(2): 139-145.
LI W, WANG H L, ZHANG J H, et al. Experimental study on mechanical properties and microstructure of powdered coal gangue concrete[J]. Journal of Drainage and Irrigation Machinery Engineering, 2023, 41(2): 139-145 (in Chinese).
[25] 乔立冬, 姚占全, 王宗熙, 等. 煤矸石对混凝土宏微观性能的灰熵分析[J]. 排灌机械工程学报, 2022, 40(1): 30-34+54.
QIAO L D, YAO Z Q, WANG Z X, et al. Grey entropy analysis of coal gangue on macro and micro properties of concrete[J]. Journal of Drainage and Irrigation Machinery Engineering, 2022, 40(1): 30-34+54 (in Chinese).
[26] DONG E L, YU R, FAN D Q, et al. Absorption-desorption process of internal curing water in ultra-high performance concrete (UHPC) incorporating pumice: from relaxation theory to dynamic migration model[J]. Cement and Concrete Composites, 2022, 133: 104659.
[27] FRIEDEMANN K, STALLMACH F, KRGER J. NMR diffusion and relaxation studies during cement hydration: a non-destructive approach for clarification of the mechanism of internal post curing of cementitious materials[J]. Cement and Concrete Research, 2006, 36(5): 817-826.
[28] ZHANG L C, ZHOU J K. Fractal characteristics of pore structure of hardened cement paste prepared by pressurized compact molding[J]. Construction and Building Materials, 2020, 259: 119856.
[29] JIN S S, ZHANG J X, HAN S. Fractal analysis of relation between strength and pore structure of hardened mortar[J]. Construction and Building Materials, 2017, 135: 1-7.
[30] 张广泰, 耿天娇, 鲁海波, 等. 冻融循环下沙漠砂纤维混凝土损伤模型研究[J]. 硅酸盐通报, 2021, 40(7): 2225-2231.
ZHANG G T, GENG T J, LU H B, et al. Damage model of desert sand fiber reinforced concrete under freeze-thaw cycles[J]. Bulletin of the Chinese Ceramic Society, 2021, 40(7): 2225-2231 (in Chinese).
[31] ZHAO Y, LIAN S L, BI J, et al. Study on freezing-thawing damage mechanism and evolution model of concrete[J]. Theoretical and Applied Fracture Mechanics, 2022, 121: 103439.
[32] 李金玉, 彭小平, 邓正刚, 等. 混凝土抗冻性的定量化设计[J]. 混凝土, 2000(12): 61-65.
LI J Y, PENG X P, DENG Z G, et al. Quantitative design on the frost-resistance of concrete[J]. Concrete, 2000(12): 61-65 (in Chinese).