A performance study of hydrophobically modified coal gangue mortar
), Abstract
Coal gangue has the characteristics of complex physical and chemical properties, low strength, loose and porous, which limit its extensive use in building materials. In this paper, coal gangue was modified by soaking in hydrophobic solution under uncalcining and non-prewetting conditions. The basic characteristics of coal gangue before and after modification was systematically studied, and hydrophobically modified coal gangue mass substitution rates of 0%, 30%, 50%, 70% and 100% were set. Contact angel, flexural strength, compressive strength, electric flux were used as characteristic parameters to evaluate the influence of modified coal gangue replacement rate on the basic properties of mortar under different substitution rates.Results showed that, by using the binary cooperative complementary method, when the replacement rate of modified coal gangue was lss than 50%, the hydrophobic state of the surface of coal gangue mortar could be achieved. As the replacement rate of modified coal gangue increases, the compressive strength showed a decreasing trend, the maximum decrease was 15.7% compared with none modified coal gangue added. The 28 d compressive strength was 58.5 MPa with 30% replacement rate of modified coal gangue. The electric flux was less than 250 C under different modified coal gangue replacement rate, which indicated excellent resistance to chloride permeability. When the modified coal gangue replacement rate is 30%, the electric flux was the smallest (130 C). The hydrophobic modification method could ensure good mechanical strength and resistance to chloride penetration under the condition of uncalcined and non-prewetted coal gangue, which fully utilizes coal gangue.
References
Li J Y, Wang J M. Comprehensive utilization and environmental risks of coal gangue: a review[J]. Journal of Cleaner Production, 2019, 239: 117946.
Liu H B, Liu Z L. Recycling utilization patterns of coal mining in China[J]. Resources, Conservation and Recycling, 2010, 54: 1331-1340.
Mohammed A, Mudavath H, Arif A B M. Characte-rization studies on coal gangue for sustainable geotechnics[J]. Innovative Infrastructure Solutions, 2020, 5: 15.
Ge Linhan, Du Hui, Zhou Chunxia. Harmfulness of coal gangue and it's recycling utilization and development trend[J]. Coal Technology, 2010, 29(7): 9-11.
Gao Y J, Huang H J, Tang W J, et al. Preparation and characterization of a novel porous silicate material from coal gangue[J]. Microporous and Mesoporous Materials, 2015, 217: 210-218.
National Development and Reform Commission. Annual report on comprehensive utilization of resources in China[J]. Renewable Resources and Circular Economy, 2014, 7(10): 3-8.
Li Shaowei, Zhou Mei, Zhang Limin. Properties of spontaneous combustion coal gangue coarse aggregate and its influence on concrete[J]. Journal of Building Materials, 2020, 23(2): 334-340.
Cui Zhenglong, Hao Jingli, Chen Long, et al. Experimental study on strength and drying shrinkage crack of spontaneous combustion gangue concrete[J]. Non-Metallic Mines, 2015, 38(6): 76-78.
Li Yongjing, Cao Shuang, Xing Yang, et al. Experimental study on the drying shrinkage performance of the concrete w ith coal gangue aggregate[J]. Concrete, 2016, 11: 95-97.
Wang Aiguo, Zhu Yuanyuan, Xu Haiyan, et al. Research progress on coal gangue aggregate for concrete[J]. Bulletin of thr Chinese Ceramic Society, 2019, 38(7): 2076-2086.
Tian Lei, Qiu Liuchao. Progress of (super) hydrophobic cement-based materials[J]. Materials Report, 2021, 35(19): 19070-19080.
Song J L, Zhao D Y, Han Z J, et al. Super-robust superhydrophobic concrete[J]. Journal of Materials Chemistry A, 2017, 5, 14542.
Song J L, Li Y X, Xu W, et al. Inexpensive and non-fluorinated superhydrophobic concrete coating for anti-icing and anti-corrosion[J]. Journal of Colloid and Interface Science, 2019, 541: 86-92.
Cheng Wenqing, Wang Shaojie, Liu Fusheng, et al. Study on simplified classification method of coal gangue used as vegetation concrete coarse aggregate[J]. New Building Materials, 2017, 11: 48-50.
Jiang Lei. Super-hydrophobic nanoscale interface materials: from natural to artificial[J]. Science & Technology Review, 2005, 23(2): 4-8.
Qiu Jisheng, Hou Bowen, Guan Xiao, et al. Effect of physical and chemical properties of coal gangue under different stratas on compressive strength of concrete[J]. Non-Metallic Mines, 2019, 42(2): 29-32.
Shi Huisheng, Shi Tao, Chen Baochun, et al. Research of chloride ion diffusivity in reactive powder concrete with blast-furnace slag[J]. Journal of Tongji Universit: Natural Science, 2006, 34(1): 93-96.
Ma Hongqiang, Yi Cheng, Zhou Honguang, et al. Compressive strength and durability of coal gangue aggregate concrete[J]. Materials Reports B, 2018, 32(7): 2390-2395.
Li Yongjing, Yue Weiqi, Pan Cheng, et al. Performance study of surface activated coal gangue aggregate cement mortar[J]. Non-Metallic Mines, 2017, 40(6): 36-38.
Wang A G, Liu P, Mo L W, et al. Mechanism of thermal activation on granular coal gangue and its impact on the performance of cement mortars[J]. Journal of Building Engineering, 2022, 45: 103616.
Zhou Mei, Tian Boyu, Wang Qiang, et al. Experimental study on the influence of spontaneous combustion gangue coarse aggregate on sand lightweight concrete performance[J]. Bulletin of thr Chinese Ceramic Society, 2013, 32(11): 2231-2237.
Yu P, Kirkpatrick R J, Poe B, et al. Structure of calcium silicate hydrate (C-S-H): Near-, Mid-, and Far- infrared spectroscopy[J]. Journal of the American Ceramic Society, 1999, 82(3): 742-748.
京公网安备11010802044758号