One of the most active fields of research embraced by many disciplines, including civil engineering, is material reuse. It is known that ceramics wastes from various construction and demolition sites and manufacturing...One of the most active fields of research embraced by many disciplines, including civil engineering, is material reuse. It is known that ceramics wastes from various construction and demolition sites and manufacturing processes are dumped away into the environment, resulting in the pollution that threatens both agriculture and public health. Therefore, the utilization of ceramic waste in construction industries would help to protect the environment from such pollutions. This paper presents the results of an experimental analysis of the effects of partial replacement of coarse aggregates, fine aggregates, and ordinary Portland cement with the ceramic waste, at percentage levels of 0%, 5%, 10%, and 20%;and the assessment of the strength property of the concrete produced with optimum combination of the constituents. Compressive strengths of this concrete were determined at 7, 28, and 56 days of curing using 150 </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> 150 </span><span style="font-family:Verdana;">×</span><span><span style="font-family:Verdana;"> 150 mm cube specimens. Test results showed that the compressive strength of the concrete decreased as the content of ceramic waste present in the concrete increased. Thus, concrete produced from the partial replacement of ordinary Portland cement with ground ceramics gave compressive strengths of 16.6 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and 13.4 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> at 5% and 20% replacement levels respectively. Similarly, the compressive strengths of concrete from the partial replacement of sand with fine ceramics were 13.8 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and 10.9 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for 5% a展开更多
The effects of carbon dioxide (CO_(2)) curing conditions (temperature,relative humidity and CO_(2) curing time) on the physical properties of recycled coarse aggregate (RCA) with varying attached mortar (AM) contents ...The effects of carbon dioxide (CO_(2)) curing conditions (temperature,relative humidity and CO_(2) curing time) on the physical properties of recycled coarse aggregate (RCA) with varying attached mortar (AM) contents were studied.Before and after CO_(2) curing,the physical properties in terms of the apparent density,water absorption and crushing value of RCA were tested and the quality of RCA was determined.Besides,scanning electron microscope was used to observe the microstructure of RCA.Results show that the physical properties variation of RCA with higher AM content are more significant,and the quality of RCA with lower AM content is easier to be upgraded during CO_(2) curing.The physical properties of RCA with 40.8% AM content are earlier stable than that with no less than 44.5% AM content during CO_(2) curing.The optimal temperature and relative humidity are 50 ℃ and 55% for CO_(2) curing,respectively.CO_(2) curing is incapable of upgrading the quality of RCA with AM no less than 50.6%.The quality of RCA with 44.5% AM content can be upgraded only under the optimum CO_(2) curing conditions.Under relative humidity higher than 40% and the CO_(2) curing time more than 12 h,CO_(2) curing upgrades the quality of RCA with 40.8% AM content.展开更多
The structure and excited state properties of the H- and J-aggregates of the marine carbonyl carotenoid, fucoxanthin(Fx), were studied by various spectroscopic methods, and compared with those of Fx monomers in polar ...The structure and excited state properties of the H- and J-aggregates of the marine carbonyl carotenoid, fucoxanthin(Fx), were studied by various spectroscopic methods, and compared with those of Fx monomers in polar organic solvents. The fluorescent analysis indicated tliat the higher vibronic states of S2 contribute more to populating the S1 state, from which fluorescent emission mainly originates. Resonance Raman and density functional theory calculations confirmed the ‘card-packed' and chead-to-taiF structures of the H- and J-aggregates of Fx, respectively. An fs time-resolved absorption study proved the coexistence of Si and intramolecular charge transfer relaxation pathways upon excitation to the S2 state for both tlie monomers and aggregates.展开更多
文摘One of the most active fields of research embraced by many disciplines, including civil engineering, is material reuse. It is known that ceramics wastes from various construction and demolition sites and manufacturing processes are dumped away into the environment, resulting in the pollution that threatens both agriculture and public health. Therefore, the utilization of ceramic waste in construction industries would help to protect the environment from such pollutions. This paper presents the results of an experimental analysis of the effects of partial replacement of coarse aggregates, fine aggregates, and ordinary Portland cement with the ceramic waste, at percentage levels of 0%, 5%, 10%, and 20%;and the assessment of the strength property of the concrete produced with optimum combination of the constituents. Compressive strengths of this concrete were determined at 7, 28, and 56 days of curing using 150 </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> 150 </span><span style="font-family:Verdana;">×</span><span><span style="font-family:Verdana;"> 150 mm cube specimens. Test results showed that the compressive strength of the concrete decreased as the content of ceramic waste present in the concrete increased. Thus, concrete produced from the partial replacement of ordinary Portland cement with ground ceramics gave compressive strengths of 16.6 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and 13.4 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> at 5% and 20% replacement levels respectively. Similarly, the compressive strengths of concrete from the partial replacement of sand with fine ceramics were 13.8 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and 10.9 N/mm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for 5% a
基金Funded by the National Natural Science Foundation of China (Nos. 52078068, 52108190)Changzhou Science and Technology Project (No. CJ20200079)Postgraduate Research&Practice Innovation Program of Jiangsu Province (No. KYCX21_2846)。
文摘The effects of carbon dioxide (CO_(2)) curing conditions (temperature,relative humidity and CO_(2) curing time) on the physical properties of recycled coarse aggregate (RCA) with varying attached mortar (AM) contents were studied.Before and after CO_(2) curing,the physical properties in terms of the apparent density,water absorption and crushing value of RCA were tested and the quality of RCA was determined.Besides,scanning electron microscope was used to observe the microstructure of RCA.Results show that the physical properties variation of RCA with higher AM content are more significant,and the quality of RCA with lower AM content is easier to be upgraded during CO_(2) curing.The physical properties of RCA with 40.8% AM content are earlier stable than that with no less than 44.5% AM content during CO_(2) curing.The optimal temperature and relative humidity are 50 ℃ and 55% for CO_(2) curing,respectively.CO_(2) curing is incapable of upgrading the quality of RCA with AM no less than 50.6%.The quality of RCA with 44.5% AM content can be upgraded only under the optimum CO_(2) curing conditions.Under relative humidity higher than 40% and the CO_(2) curing time more than 12 h,CO_(2) curing upgrades the quality of RCA with 40.8% AM content.
基金Supported by the National Natural Science Foundation of China(Nos.21273282,21673289,21673288,21173265)the International Cooperation Project Between China and Russia(NSFC-RFBR)(No.21411130185).
文摘The structure and excited state properties of the H- and J-aggregates of the marine carbonyl carotenoid, fucoxanthin(Fx), were studied by various spectroscopic methods, and compared with those of Fx monomers in polar organic solvents. The fluorescent analysis indicated tliat the higher vibronic states of S2 contribute more to populating the S1 state, from which fluorescent emission mainly originates. Resonance Raman and density functional theory calculations confirmed the ‘card-packed' and chead-to-taiF structures of the H- and J-aggregates of Fx, respectively. An fs time-resolved absorption study proved the coexistence of Si and intramolecular charge transfer relaxation pathways upon excitation to the S2 state for both tlie monomers and aggregates.
