Reinforced concrete （RC） beams externally bonded with basalt fiber reinforced polymer （BFRP） are experimentally investigated by using different numbers of bonding plies, transverse anchorages as well as the initia...Reinforced concrete （RC） beams externally bonded with basalt fiber reinforced polymer （BFRP） are experimentally investigated by using different numbers of bonding plies, transverse anchorages as well as the initial conditions of strengthened beams. The performances of the BFRP strengthening are compared with those of the carbon fiber reinforced polymer （CFRP） and the glass fiber reinforced polymer （GFRP） under the same experimental condition. Experimental results indicate that the strength and ductility of the strengthened beam with two plies of the BFRP are improved remarkably than those with one ply. The strengthening effects of the BFRP lie between those of the CFRP and the GFRP. The BFRP strengthening is little influenced by pre-cracks of concrete. Most failures are caused by interfaciai debonding induced by flexural cracks in the experiment. Clamping of Uwraps along the whole beam is less efficient than endpoint anchorage for increasing the ultimate load of the strengthened beam. Finally, the models suggested by the five guidelines for predicting the debonding strain of the CFRP are extended to the BFRP and the conservative estimates of the debonding strain of the BFRP are given as well.展开更多
Mine drainage could be filtered and purified through goaf. This innovative technique shows merits, such as high treatment efficiency, remarkable economic benefit and extensive wastewater recycle use. However, it was d...Mine drainage could be filtered and purified through goaf. This innovative technique shows merits, such as high treatment efficiency, remarkable economic benefit and extensive wastewater recycle use. However, it was detected that capacities of purifying mine drainage for goaf were decreased after a period of application. As a result, the effluent could not meet the standard of recycle water. To solve the problem, coagulant was considered to add into mine drainage reducing its high turbid degrees to certain level. After the preliminary flocculation treatment, mine drainage was piped into goaf to purify. In this way, the load of goaf was eased up. Its usage time was also prolonged. Therefore, this paper carried out the coagulation-flocculation jar test for mine drainage to discuss the flocculation parameters. By the experiment, 10 % iron trichloride is selected from four inorganic coagulants as the optimum coagulant. The optimum dose, PH value and sedirs6-7 and 25 min. Velocity mentation time are respectively 2 mL per 800 mL Wastewater gradient G during the process of mixing and reaction is 696 .And the value of GT is 6.264 × 10^5. The values of G and GT will supply the basis for the design of flocculation pool in the project. The flocculation parameters will be significant for the reference of practice.展开更多
Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid t...Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid tied to a skeletal frame. The three patterns of slice reinforcement were used to reinforce cementitious slabs with or without conventional wire mesh reinforcement. The slabs were square and simply supported at their periphery with a clear span of 400 mm, and concentrically patch loaded to failure. For specimens designed to fail in flexure, the specimens reinforced with CFRP slices showed a smoother load deflection response and higher flexural capacity. For slabs designed to fail in punching shear, adding CFRP slices showed significant improvement in the ultimate shear capacity and ductility over reference specimens. Well distributed fine cracks of smaller width than control specimens were developed and no matrix spalling was observed.展开更多
The electrically charged flocculation agent Kiyomaru was made on the basis of activating surface sand, clay, volcanic ash and then combined with strong electrical charge on the surface. Thus, it is the flocculant with...The electrically charged flocculation agent Kiyomaru was made on the basis of activating surface sand, clay, volcanic ash and then combined with strong electrical charge on the surface. Thus, it is the flocculant with natural and inorganic origin including 24.7% Na, 11.5% Al, 19.6% Si, 22.5% S, 1.8% K, 19.0% Ca and 0.9% Fe. The experimental results showed that the Kiyomaru is a flocculation agent with ability to treat the turbidity and suspended solid in the catfish farming waters with very high sedimentation rate and removal efficiency. The efficiency of turbidity removal is from 98.7% to 99.1%, while that for TSS removal is from 93.5% to 95.2% using 0.2 mg/L of the flocculation agent. Beside those, the agent can remove the organic matters （BOD, COD） from 21.4% to 26.7%, Total N from 32.4% to 33.9% and Total P from 85.4% to 89.3%. When the concentration of this flocculate agent is 0.2 g/L, turbidity treatment efficiency can range from 98.7% to 99.1%; TSS treatment efficiency can range from 93.5% to 95.2%. Besides, this flocculation agent is also capable of reducing 21.4%-26.7% of the organic matter, 32.4% to 33.9% of Total N and 85.4% to 89.3% of Total P.展开更多
It is a common method to strengthen the damaged RC structures with bonded steel plates. At present the ultimate bearing ca- pacity of RC structures strengthened with bonded steel plates is calculated mostly using the ...It is a common method to strengthen the damaged RC structures with bonded steel plates. At present the ultimate bearing ca- pacity of RC structures strengthened with bonded steel plates is calculated mostly using the theory based on the test. Four beams, including one reference beam, two strengthened concrete beams in primary force and secondary force respectively, and one strengthened concrete beam which was not anchored enough, were tested under four-point bending (4PB) in order to get the data of strain of longitudinal bars, bonded bottom steel plate in tension and deflection of beams in the middle span. The experimental program was supported by a three-dimensioned finite analysis using ABAQUS. At the end of experiments and finite analysis, it is concluded that the investing strengthening technique can significantly improve the load-carrying capacity and the phenomenon of stress concentration at the end of interface, as well as the damage at interface, can be well simulated with cohesive element provided by ABAQUS.展开更多
文摘Reinforced concrete （RC） beams externally bonded with basalt fiber reinforced polymer （BFRP） are experimentally investigated by using different numbers of bonding plies, transverse anchorages as well as the initial conditions of strengthened beams. The performances of the BFRP strengthening are compared with those of the carbon fiber reinforced polymer （CFRP） and the glass fiber reinforced polymer （GFRP） under the same experimental condition. Experimental results indicate that the strength and ductility of the strengthened beam with two plies of the BFRP are improved remarkably than those with one ply. The strengthening effects of the BFRP lie between those of the CFRP and the GFRP. The BFRP strengthening is little influenced by pre-cracks of concrete. Most failures are caused by interfaciai debonding induced by flexural cracks in the experiment. Clamping of Uwraps along the whole beam is less efficient than endpoint anchorage for increasing the ultimate load of the strengthened beam. Finally, the models suggested by the five guidelines for predicting the debonding strain of the CFRP are extended to the BFRP and the conservative estimates of the debonding strain of the BFRP are given as well.
文摘Mine drainage could be filtered and purified through goaf. This innovative technique shows merits, such as high treatment efficiency, remarkable economic benefit and extensive wastewater recycle use. However, it was detected that capacities of purifying mine drainage for goaf were decreased after a period of application. As a result, the effluent could not meet the standard of recycle water. To solve the problem, coagulant was considered to add into mine drainage reducing its high turbid degrees to certain level. After the preliminary flocculation treatment, mine drainage was piped into goaf to purify. In this way, the load of goaf was eased up. Its usage time was also prolonged. Therefore, this paper carried out the coagulation-flocculation jar test for mine drainage to discuss the flocculation parameters. By the experiment, 10 % iron trichloride is selected from four inorganic coagulants as the optimum coagulant. The optimum dose, PH value and sedirs6-7 and 25 min. Velocity mentation time are respectively 2 mL per 800 mL Wastewater gradient G during the process of mixing and reaction is 696 .And the value of GT is 6.264 × 10^5. The values of G and GT will supply the basis for the design of flocculation pool in the project. The flocculation parameters will be significant for the reference of practice.
文摘Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid tied to a skeletal frame. The three patterns of slice reinforcement were used to reinforce cementitious slabs with or without conventional wire mesh reinforcement. The slabs were square and simply supported at their periphery with a clear span of 400 mm, and concentrically patch loaded to failure. For specimens designed to fail in flexure, the specimens reinforced with CFRP slices showed a smoother load deflection response and higher flexural capacity. For slabs designed to fail in punching shear, adding CFRP slices showed significant improvement in the ultimate shear capacity and ductility over reference specimens. Well distributed fine cracks of smaller width than control specimens were developed and no matrix spalling was observed.
文摘The electrically charged flocculation agent Kiyomaru was made on the basis of activating surface sand, clay, volcanic ash and then combined with strong electrical charge on the surface. Thus, it is the flocculant with natural and inorganic origin including 24.7% Na, 11.5% Al, 19.6% Si, 22.5% S, 1.8% K, 19.0% Ca and 0.9% Fe. The experimental results showed that the Kiyomaru is a flocculation agent with ability to treat the turbidity and suspended solid in the catfish farming waters with very high sedimentation rate and removal efficiency. The efficiency of turbidity removal is from 98.7% to 99.1%, while that for TSS removal is from 93.5% to 95.2% using 0.2 mg/L of the flocculation agent. Beside those, the agent can remove the organic matters （BOD, COD） from 21.4% to 26.7%, Total N from 32.4% to 33.9% and Total P from 85.4% to 89.3%. When the concentration of this flocculate agent is 0.2 g/L, turbidity treatment efficiency can range from 98.7% to 99.1%; TSS treatment efficiency can range from 93.5% to 95.2%. Besides, this flocculation agent is also capable of reducing 21.4%-26.7% of the organic matter, 32.4% to 33.9% of Total N and 85.4% to 89.3% of Total P.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11132003, 11002048, 10972072)the Special Fund of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering at Hohai University (Grant Nos. 2011585912, 2009585912)
文摘It is a common method to strengthen the damaged RC structures with bonded steel plates. At present the ultimate bearing ca- pacity of RC structures strengthened with bonded steel plates is calculated mostly using the theory based on the test. Four beams, including one reference beam, two strengthened concrete beams in primary force and secondary force respectively, and one strengthened concrete beam which was not anchored enough, were tested under four-point bending (4PB) in order to get the data of strain of longitudinal bars, bonded bottom steel plate in tension and deflection of beams in the middle span. The experimental program was supported by a three-dimensioned finite analysis using ABAQUS. At the end of experiments and finite analysis, it is concluded that the investing strengthening technique can significantly improve the load-carrying capacity and the phenomenon of stress concentration at the end of interface, as well as the damage at interface, can be well simulated with cohesive element provided by ABAQUS.
