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In this study, the workability, mechanical properties and microstructure of geopolymer grouting material (GGM) containing high-calcium basalt fiber (HCBF) have been investigated. Basalt fibers with different lengths were selected as the reinforcement and added various contents into geopolymer prepared by slag and fly ash. The setting times, compressive and flexural strengths and water resistance were used to evaluate the workability and mechanical properties of geopolymer. The development of microstructure was characterized by SEM and MIP techniques. Results show that the initial and final setting times, compressive and flexural strengths are increased with the content of HCBF, while the fluidity and drying shrinkage is reduced. On the basis of SEM and MIP tests, the incorporation of HCBF promoted the densification and refined the pore, and consequently reducing the porosity of geopolymer. Generally, the comprehensive performances of geopolymer grouting material mixed with 6 mm HCBF were better than that mixed with 3 mm at the same dosage. Through the analysis, the addition of calcium-high basalt fiber led to the development of C-S-H and C-A-S-H and combined with N-A-S-H or hybrid C(N)-A-S-H gel system, which further enhanced the performance of geopolymer grouting material.
Jun Xu; Aihong Kang; Zhengguang Wu; Peng Xiao; Yongfan Gong. Effect of high-calcium basalt fiber on the workability, mechanical properties and microstructure of slag-fly ash geopolymer grouting material. Construction and Building Materials 2021, 302, 124089 .
AMA StyleJun Xu, Aihong Kang, Zhengguang Wu, Peng Xiao, Yongfan Gong. Effect of high-calcium basalt fiber on the workability, mechanical properties and microstructure of slag-fly ash geopolymer grouting material. Construction and Building Materials. 2021; 302 ():124089.
Chicago/Turabian StyleJun Xu; Aihong Kang; Zhengguang Wu; Peng Xiao; Yongfan Gong. 2021. "Effect of high-calcium basalt fiber on the workability, mechanical properties and microstructure of slag-fly ash geopolymer grouting material." Construction and Building Materials 302, no. : 124089.
In this paper, a high-performance geopolymer grouting material based on slag and fly ash was developed and the properties were investigated. The fluidity, setting time, compressive strength, water resistance and drying shrinkage were studied to evaluate the workability and mechanical properties of geopolymer grouting material (GGM). X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the microstructural performance of GGM. The results show that the concentration of alkaline activator and slag content plays a significant role in properties of GGM and the optimum formula has been obtained. In the course of the study, the effect of concentration of alkaline activator and the content of slag on the workability and mechanical performance of GGM is different. All properties of geopolymer were considered comprehensively, the slag content and concentration of alkaline activator were 70% and 37%, which indicated that the geopolymer grouting material made from slag and fly ash could meet the requirements of concrete reinforcement well and was friendly to the environment.
Jun Xu; Ai Hong Kang; Zheng Guang Wu; Peng Xiao; Bo Li; Yi Miao Lu. Research on the Formulation and Properties of a High-Performance Geopolymer Grouting Material Based on Slag and Fly Ash. KSCE Journal of Civil Engineering 2021, 25, 3437 -3447.
AMA StyleJun Xu, Ai Hong Kang, Zheng Guang Wu, Peng Xiao, Bo Li, Yi Miao Lu. Research on the Formulation and Properties of a High-Performance Geopolymer Grouting Material Based on Slag and Fly Ash. KSCE Journal of Civil Engineering. 2021; 25 (9):3437-3447.
Chicago/Turabian StyleJun Xu; Ai Hong Kang; Zheng Guang Wu; Peng Xiao; Bo Li; Yi Miao Lu. 2021. "Research on the Formulation and Properties of a High-Performance Geopolymer Grouting Material Based on Slag and Fly Ash." KSCE Journal of Civil Engineering 25, no. 9: 3437-3447.
Pavement runoff is recognized as a primary source of non-point pollution in the urban area. It is difficult to treat the runoff-pollutants from different pavements because of complex distribution characteristics and influencing factors. This study presents the results of an experimental investigation aimed at determining the impact of three types of urban pavements, i.e., portland cement concrete pavements (PCC), dense asphalt concrete pavements (DAC) and permeable asphalt concrete pavements (PAC) on the rainfall-runoff process, concentration levels, and spatiotemporal distribution characteristics of typical runoff-pollutants. Runoff samples from the three types of urban pavements were collected and analyzed at different time-intervals beginning from runoff formation. The results indicated that PAC could better intercept and retain runoff-pollutants than DAC and PCC. In addition to the types of pavements, road-traffic characteristics and the surrounding environment significantly impacted the event mean concentrations of the selected rainfall events. Concentrations of suspended solids and heavy metals were higher at intersections and crosswalks, while those of organic pollutants were high in commercial areas. Besides, three parameters were proposed to characterize the first-flush effect intensity for runoff-pollutants. These findings help better understand the spatiotemporal distribution characteristics of runoff-pollutants from different types of urban pavements, which could also help strategically select measures to treat pavement runoff pollution.
Changjiang Kou; Yanjuan Qi; Aihong Kang; Haotian Hu; Xing Wu. Spatiotemporal distribution characteristics of runoff-pollutants from three types of urban pavements. Journal of Cleaner Production 2021, 292, 125885 .
AMA StyleChangjiang Kou, Yanjuan Qi, Aihong Kang, Haotian Hu, Xing Wu. Spatiotemporal distribution characteristics of runoff-pollutants from three types of urban pavements. Journal of Cleaner Production. 2021; 292 ():125885.
Chicago/Turabian StyleChangjiang Kou; Yanjuan Qi; Aihong Kang; Haotian Hu; Xing Wu. 2021. "Spatiotemporal distribution characteristics of runoff-pollutants from three types of urban pavements." Journal of Cleaner Production 292, no. : 125885.
The concentrations of pollutants in urban pavement runoff are normally higher than those in other urban surface runoff, which causes serious problems in protecting the environment of receiving water and soils. The purpose of this study was to propose a source pollution control measure based on the spatial-temporal distribution characteristics of the runoff pollutants at urban pavement sites. Therefore, samples from pavement runoff were collected and tested for analyzing the spatial-temporal distribution characteristics. Then, infiltration tests were conducted on selected purification materials to evaluate their purification ability to the simulated pavement runoff. Results indicated that heavy metals Zn and Pb were at high concentrations near the intersection, the reason being the frequent braking of vehicles at this site. The level of suspended solids was far higher than the limitation in the standard near the site where massive human activities occurred. Besides, the cumulative amounts of all kinds of pollutants tended to be stable with the extension of rainfall duration. The logarithmic function was found to fit the experimental data well. Finally, the pavement runoff was categorized into different situations. The combinations of purification materials were recommended and integrated into a source control measure for the treatments of different pollution situations, which made the most use of each purification material and ensured the high elimination efficiency of different pollutants.
Changjiang Kou; Aihong Kang; Peng Xiao; Peter Mikhailenko; Hassan Baaj; Lu Sun; Zhengguang Wu. A Source Pollution Control Measure Based on Spatial-Temporal Distribution Characteristic of the Runoff Pollutants at Urban Pavement Sites. Applied Sciences 2018, 8, 1802 .
AMA StyleChangjiang Kou, Aihong Kang, Peng Xiao, Peter Mikhailenko, Hassan Baaj, Lu Sun, Zhengguang Wu. A Source Pollution Control Measure Based on Spatial-Temporal Distribution Characteristic of the Runoff Pollutants at Urban Pavement Sites. Applied Sciences. 2018; 8 (10):1802.
Chicago/Turabian StyleChangjiang Kou; Aihong Kang; Peng Xiao; Peter Mikhailenko; Hassan Baaj; Lu Sun; Zhengguang Wu. 2018. "A Source Pollution Control Measure Based on Spatial-Temporal Distribution Characteristic of the Runoff Pollutants at Urban Pavement Sites." Applied Sciences 8, no. 10: 1802.
Two kinds of rubber modified asphalts were investigated and compared with virgin asphalt. In order to get closer to engineering practice, different combinations of four environmental factors were merged into the laboratory aging simulation. Subsequently, conventional property tests, including softening point, viscosity, creep stiffness, creep rate, and fatigue cracking were conducted on asphalt samples. The performance difference of asphalt before and after aging was selected as an evaluation index for asphalt aging degree. The results indicate that two kinds of rubber modified asphalts show stronger resistant ability to temperature deformation and better resistance to traffic loading than virgin asphalt in all kinds of environmental factors combinations. Tests on chemical analyses were conducted to investigate the asphalt aging characteristics. The apparent morphology of rubber modified asphalts are described in detail under an environment scanning electron microscope (ESEM). The damage condition reflected in images reveals the aging degree caused by multiple environmental factors. Moreover, the thermogravimetric analysis (TG) confirms that three kinds of asphalts can maintain thermal stability in various environments. Additionally, new characteristic functional groups were not detected in the infrared (IR) spectra of rubber modified asphalts, which means they have stable antioxidant properties given that their oxidation degrees change slightly throughout the aging processes.
Peng Xiao; Jiahui Zheng; Aihong Kang; Lu Sun; Yingqian Wang. Aging Characteristics of Rubber Modified Asphalts in Different Environmental Factors Combinations. Applied Sciences 2017, 7, 806 .
AMA StylePeng Xiao, Jiahui Zheng, Aihong Kang, Lu Sun, Yingqian Wang. Aging Characteristics of Rubber Modified Asphalts in Different Environmental Factors Combinations. Applied Sciences. 2017; 7 (8):806.
Chicago/Turabian StylePeng Xiao; Jiahui Zheng; Aihong Kang; Lu Sun; Yingqian Wang. 2017. "Aging Characteristics of Rubber Modified Asphalts in Different Environmental Factors Combinations." Applied Sciences 7, no. 8: 806.