Mechanical Properties and Microscopic Mechanism of Mixed Mortar with Gangue Machine-Made Sand and Eolian Sand

Abstract

Abstract: Mixed mortar is a new type of mortar that is prepared by using gangue machine-made sand and eolian sand to replace river sand in different proportion (equal mass). To explore the change rule and microscopic mechanism of the basic mechanical properties of mixed mortar, the mixed mortar specimens were prepared with the eolian sand of Mu Us Desert and the gangue machine-made sand of the Daliuta Coal Mine. The compressive strength change rules of mixed mortar with the two kinds of sand mixed ratio, curing age, and mixed sand fineness modulus were studied, and the internal mechanism of the strength change rule was revealed. The results show that with the increase of the proportion of eolian sand, the strength of mixed mortar increases first and then decreases, and the optimal mixing ratio of gangue machine-made sand and eolian sand is 6 ∶4 (mass ratio). The compressive strength of mixed mortar and the fineness modulus of mixed sand satisfy the quadratic function relationship. When the fineness modulus of mixed sand is 2.20, the mechanical properties of mortar are the best. The particles of different particle sizes of mixed sand fill each other, which reduces the internal pores of the mortar. The addition of an appropriate amount of eolian sand can disperse the large bubbles retained in the mortar into tiny bubbles and improve the structure of the mortar. The concepts of beneficial pore and harmful pore are proposed. Based on the pore structure parameters, the change process of mechanical strength of mortar is explained, which shows that the compressive strength of mortar is the result of the combined action of its internal porosity and pore size distribution range. The appropriate amount of aeolian sand mixed with gangue machine-made sand is conducive to the hydration reaction, which has a “compensation effect” on the structure. However, with the further increase of aeolian sand content, due to the defects of aeolian sand itself, this “compensation effect” cannot make up for the defects of the material itself.

Key words: mixed mortar, compressive strength, microscopic mechanism, pore structure, harmful pore, compensation effect action

CLC Number:

TU528

QIU Jisheng, NIU Gaohui, LI Leilei, FENG Zeping, LI Le. Mechanical Properties and Microscopic Mechanism of Mixed Mortar with Gangue Machine-Made Sand and Eolian Sand[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(12): 4424-4433.

References

[1] 贾敏. 煤矸石综合利用研究进展[J]. 矿产保护与利用, 2019, 39(4): 46-52.
JIA M. Research progress on comprehensive utilization of coal gangue[J]. Mineral Protection and Utilization, 2019, 39(4): 46-52 (in Chinese).
[2] 朱宝忠, 谢承卫. 煤矸石综合利用的研究进展[J]. 贵州大学学报(自然科学版), 2007, 24(5): 520-525.
ZHU B Z, XIE C W. Progress in comprehensive utilizations of coal gangue[J]. Journal of Guizhou University (Natural Sciences), 2007, 24(5): 520-525 (in Chinese).
[3] 王新伟, 钟宁宁, 韩习运. 煤矸石堆放对土壤环境PAHs污染的影响[J]. 环境科学学报, 2013, 33(11): 3092-3100.
WANG X W, ZHONG N N, HAN X Y. Impacts of coal gangue stockpiling on polycyclic aromatic hydrocarbons pollution in soil environment[J]. Acta Scientiae Circumstantiae, 2013, 33(11): 3092-3100 (in Chinese).
[4] 雷建红. 煤矸石的污染危害与综合利用分析[J]. 能源与节能, 2017(4): 90-91+147.
LEI J H. Analysis of pollution hazards and comprehensive utilization of coal gangue[J]. Energy and Energy Conservation, 2017(4): 90-91+147 (in Chinese).
[5] 包建强, 邢永明, 刘霖. 风积砂混凝土的基本力学性能试验研究[J]. 混凝土与水泥制品, 2015(11): 8-11.
BAO J Q, XING Y P, LIU L, Experimental study on basic mechanical properties of eolian sand concrete[J]. Concrete and Cement Products, 2015(11): 8-11 (in Chinese).
[6] 刘倩, 申向东, 董瑞鑫, 等. 孔隙结构对风积砂混凝土抗压强度影响规律的灰熵分析[J]. 农业工程学报, 2019, 35(10): 108-114.
LIU Q, SHEN X D, DONG R X, et al. Grey entropy analysis of the influence of pore structure on compressive strength of eolian sand concrete[J]. Agricultural Engineering, 2019, 35(10): 108-114 (in Chinese).
[7] 维利思, 申向东, 刘倩, 等. 不同风积砂混凝土强度的影响因素研究[J]. 硅酸盐通报, 2019, 38(9): 2933-2940+2946.
WEI L S, SHEN X D, LIU Q, et al. Study on the influencing factors of different eolian sand concrete strength[J]. Bulletin of the Chinese Silicate Society, 2019, 38(9): 2933-2940+2946 (in Chinese).
[8] 董瑞鑫, 申向东, 刘倩, 等. 风积沙混凝土孔隙特征对其强度影响机理的研究[J]. 硅酸盐通报, 2019, 38(6): 1901-1907.
DONG R X, SHEN X D, LIU Q, et al. Influence mechanism of pore characteristics of aeolian sand concrete on its strength[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(6): 1901-1907 (in Chinese).
[9] 薛慧君, 申向东, 侯雨丰, 等. 风积砂混凝土力学性能及孔隙特征[J]. 排灌机械工程学报, 2021, 39(7): 720-726.
XUE H J, SHEN X D, HOU Y F, et al. Mechanical properties and pore characteristics of eolian sand concrete[J]. Journal of Drainage and Irrigation Machinery Engineering, 2021, 39(7): 720-726 (in Chinese).
[10] 王辉. 基于破碎效果分析煤矸石细集料在砂浆中的应用[J]. 散装水泥, 2022(4): 191-196.
WANG H. Analysis of the application of coal gangue fine aggregate in mortar based on crushing effect[J]. Bulk Cement, 2022(4): 191-196 (in Chinese).
[11] 汪洪波, 孙学祥, 姜生辉, 等. 煤矸石机制砂细度模数对胶砂性能影响研究[J]. 水泥工程, 2021(2): 12-15.
WANG H B, SUN X X, JIANG S H, et al. Study on the influence of fineness modulus of manufactured coal gangue sand on properties of mortar[J]. Cement Engineering, 2021(2): 12-15 (in Chinese).
[12] 孙钢柱, 关罡, 许荣盛. 煤矸石作细骨料的混凝土性能试验研究[J]. 混凝土, 2016(8): 87-89+98.
SUN G Z, GUAN G, XU R S. Experimental study on the performance of the concrete which coal gangue as fine aggregate[J]. Concrete, 2016(8): 87-89+98 (in Chinese).
[13] YUSUF Y A, OLAWUMI B A. Comparative study on strength properties of concrete made with river sand and dune sand as fine aggregate[J]. IOSR Journal of 164 Mechanical and Civil Engineering, 2015, 12(4): 71-75.
[14] DE LARRARD F. Concrete mixture proportioning: a scientific approach[M]. London: Spon Press, 1999.
[15] WHITING D, STARK D. Control of air content in concrete[R]. Report 258, National Cooperative Highway Research Program, Washington, 1983.
[16] 李玉根, 张慧梅, 陈少杰, 等. 风积砂混凝土盐冻多尺度劣化机制[J]. 复合材料学报, 2023, 40(4): 2331-2342.
LI Y G, ZHANG H M, CHEN S J, et al. Multi-scale deterioration mechanism of salt freezing of eolian sand concrete[J]. Acta Materiae Compositae Sinica, 2023, 40(4): 2331-2342 (in Chinese).
[17] 吴中伟. 混凝土科学技术近期发展方向的探讨[J]. 硅酸盐学报, 1979, 7(3): 262-270.
WU Z W. Discussion on recent development direction of concrete science and technology[J]. Bulletin of the Chinese Silicate Society, 1979, 7(3): 262-270 (in Chinese).