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Henan Shi received his M. S. degree from the School of Civil Engineering and Architecture at Beijing Jiaotong University, and is currently a Ph. D. candidate in Bridge and Tunnel Engineering at the China Academy of Railway Sciences. His research focuses on the application of recycled concrete in railway engineering, and he has authored 10 SCI/EIindexed papers.
Outline
The efficient utilization of recycled concrete powder (RCP) has attracted much attention. To break through the limitation of single activation technology of RCP, this study investigates the effects of a mechanical-microwave method on the reactivity of RCP.
The mechanical properties, hydration products, and pore structure of RCP-incorporated mortar were evaluated.
The results demonstrate that the combined activation reduces the median particle size of RCP and induces a low-frequency shift in the Si-O-T FT-IR characteristic peaks, signifying depolymerization of the silicate network and formation of highly reactive broken bond sites. Concurrently, decreased Si2p and Al2p binding energies in XPS spectra confirm enhanced surface reactivity. The 28-day strength activity index (SAI) of RCP mortar improved from 65.7 (untreated) to 82.2% under optimal activation conditions (90-min ball milling followed by 10-min microwave irradiation), outperforming solely mechanical activation by 3.6-6.1%. Furthermore, combined activation increased chemically bound water content from 22.8 to 33.7%, accompanied by a low-wavenumber shift in FT-IR peaks of hydration products. The total porosity of RCP mortar decreased from 17.2 to 14.6%, indicating a denser pore structure.
This study explores the feasibility and potential mechanism of mechanical-microwave activation of RCP, aiming to provide valuable insights for the sustainable development of materials. Using activated RCP in cement-based materials reduces the demand for cement and substantially cuts carbon emissions, thereby making a critical contribution to the construction industry's green and low-carbon transition.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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