[雙語翻譯]--土木工程專業(yè)外文翻譯---采用電沉積法修復鋼筋混凝土裂縫的愈合效果（原文）

1、 Journal of Wuhan University of Technology-Mater. Sci. Ed. Dec. 2008 917DOI 10.1007/s11595-007-6917-x Healing Effectiveness of Cracks Rehabilitation in Reinforced Concrete Using Electrodeposition Method JIAN

2、G Zhengwu1, XING Feng2, SUN Zhenping1, WANG Peiming1 (1. Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Tongji University, Shanghai 200092, China; 2. Shenzhen Key Laboratory of Civil Eng

3、ineering Durability, Shenzhen University, Shenzhen 518060, China） Abstract: An electrodeposition method and its experimental device for rehabilitation of cracks in reinforced concrete were proposed. Porous concrete is pr

4、oposed to simulate cracked con-crete, and mass increment, permeation coefficient and sound velocity of ultrasonic wave were used to be evaluating indicators of healing effectiveness of crack rehabilitation in this method

5、. Effect of currency density, concentration of electrolyte solution on healing effectiveness of porous reinforced concretes with different total void ratio was studied. The experimental results indicate that the simulati

6、on of porous concrete for cracks can reflect the healing effectiveness of electrodeposition method effectively. Total void ratio of porous concrete has little effect on healing effectiveness of electrodeposition at early

7、 ages. The higher the currency density or concentration of electrolyte so-lution is, the higher the electrodeposition rate and sound velocity in porous concrete are, and the lower the permeation coefficient of porous con

8、crete will be. Mg(OH)2 crystals produced in high current density are large, thin sheet-shaped and arranged loosely. Keywords: electrodeposition; porous; reinforced concrete; crack; healing 1 Introduction Reinforced conc

9、rete (RC) is a kind of widely used construction material for buildings, bridges, hydraulic constructions and marine projects, etc. However, RC structure will usually generate microcracks inevitably in their service life

10、under surrounding environment erosion, which reduces load bearing and durability of RC struc-tures greatly[1]. So, it is necessary to rehabilitate or repair them. According to reasons inducing cracks and their environmen

11、t conditions, many repair methods such as reinforcement, anchoring, grouting, sealing and re-placement etc are proposed[2-6]. However, these methods show certain limitations for cracks in RC structures under water enviro

12、nment. It is of great practical significance to develop new non-destructive rehabilitation methods for underwater concrete structures. Electrodeposition method is one of new developed methods for rehabilita-tion of cr

13、acks in underwater RC[7-10]. It takes advantage of the character of RC and water environment condition, puts a weak direct current between rebar in RC structures and an external electrode (an anode) and produces elec-tro

14、deposits around rebar in RC, which will form a barrier coating of inorganic insoluble compounds such as ZnO, CaCO3 and Mg(OH)2, etc in cracks and surfaces, fill cracks and seal surfaces of RC. In recent years, several st

15、udies[7,10-14] are reported on the topic about its feasibil-ity, mechanism and experimental control of rehabilitation of cracks in RC using electrodeposition method. How to simulate cracks in RC in the laboratory, preset

16、 cracks in concrete specimens and evaluate healing effectiveness of cracks in RC effectively are hot and difficult research topics of rehabilitation of cracks in RC using electrodeposition method. Currently, the two main

17、 simulating methods including splitting and cracking by salt corrosion are proposed for presetting cracks in RC[7,10,14], which has several shortcomings such as crack randomness, out of controlling of width and orientati

18、on of cracks, and difficulty in evaluating healing effective-ness of cracks using electrodeposition method. Therefore, in order to evaluate healing effectiveness of cracks reha-bilitation in RC using electrodeposition me

19、thod effec-tively, porous concrete with different total void ratio (Received: Sep. 12, 2007; Accepted: Mar. 9, 2008) JIANG Zhengwu 蔣蔣蔣 ( ): Assoc. Prof.; Ph D; E-mail: jzhw@#edu.cn Funded by the National Natural Sc

20、ience Foundation of China(50508029), Shanghai Provincial Natural Science Foundation (05zr14121)and Open Fund of Shenzhen Key Laboratory of Civil Engineering Durabilityof Shenzhen University (CED06-01) 萬方數(shù)據(jù)Journal of Wu

21、han University of Technology-Mater. Sci. Ed. Dec. 2008 9192.4 Testing methods The apparent density of porous concrete was meas-ured by a volume testing method. The porous specimens with the dimensions of 100 mm&

22、#215;100 mm×100 mm were kept in dry air for 5 h after being taken out of the curing room, which made them reach saturated sur-face–dry conditions. Then their mass and dimensions were tested. The measurement accuracy

23、 of the digital weighting scale reached ±1 g and the dimension meas-urement accuracy of the vernier caliper reached ±0.1 mm. According to the mass and volume of specimens, the apparent density of porous concret

24、e was calculated out. Three specimens were measured in each group and their average was considered as the apparent density of porous concrete. Porous RC specimens with the dimensions of 100 mm×100 mm×200 mm w

25、ere used to measure the mass increment of porous RC specimen after electrode- position. The mass of porous RC specimens was meas- ured after given healing ages. Measurement method of mass increment of porous RC specime

26、ns was similar to the measurement of apparent density of porous concrete. TVR was obtained by dividing the difference be- tween the weight (m1) of the specimens in the water and that (m2) measured following air drying

27、 for 24 h by the specimen volume. The weight of specimens was meas- ured by a pointer tension dynamometer and its accuracy reaches 1 g. Sizes of specimens were measured by a vernier caliper and its measurement accurac

28、y of size reached 1 mm. The equation used to obtain the TVR is as follows: (1) where, A is the TVR of porous concrete, %; m1 the un-derwater weight of specimen, g; m2 the weight of speci-men dried in air for 24 h, g; V1

29、 the specimen volume, cm3; ρw the density of water, kg/mm3. Compressive strength of porous concrete specimens was measured at 7 days and 28 days in accordance with Chinese test standard GBJ 81-85. There is no standa

30、rd methods and device for per- meation coefficient measurement of porous concrete in the domestic. The water permeability testing method for ordinary concrete is not suitable for porous concrete. So, a new testing dev

31、ice for permeation coefficient of porous concrete was designed in this experiment. The specific measurement detail and calculation method of permea- tion coefficient of porous concrete was described in the Ref.[15].

32、Ultrasonic wave method was used to measure the sound velocity of porous RC specimen before electro- deposition and after 28 days electrodeposition to evaluate healing effectiveness of cracks. The sound velocity of thr

33、ee couples of parallel specimen surfaces was tested. In order to avoid the experimental error induced by rebar in specimens, the testing point of ultrasonic probe was lo- cated in the middle of every couple of parallel

34、surfaces shown in Fig.3. According to the location of reinforce- ment cage in specimens, rebar had no effect on testing results. Moreover, in order to avoid the influence of moisture content in specimen on testing res

35、ults, the specimens were dried in a temperature of 105±3 ℃ be- fore tested. 3 Results and Discussion 3.1 Properties of porous concrete with different mix proportions As shown in Table 1, the porosities of porous c

36、on- crete such as apparent density and compressive strength are related with TVR of porous specimens tightly. The higher the TVR of porous specimens, the smaller the apparent density of them is. Due to different gradu

37、ation composition of aggregate, three series of porous speci- mens have different TVR, which affects healing effec- tiveness of rehabilitation differently. P2 has the highest TVR of 30%, P1 is the lowest TVR of 13.3%,

38、and TVR of P3 reaches 20.7%. 3.2 Effect of different factors on the mass increment of porous specimens after electrodeposition 3.2.1 TVR Fig.4 shows the unit volume mass increment of specimens as a function of healing

39、 time when current density of 0.5 A/m2 and Mg(NO3)2 concentration of 0.05 mol/L is given. As it shows, the unit volume mass increment of all specimens increases obviously after electrodeposition and it increases with

40、 the increase of healing time. It verifies that electrodeposition is existed in the macroscopic scale and the electrodeposits are pre- cipitated in the porous specimens. The mass increment of each series is similar in

41、 the first 7 days of healing. The mass increment of P2 is higher than those of P1 and P3 at 60 days. It indicates that TVR has little effect on elec- trodeposition process and precipitation at early healing ages, and

42、the mass increment increases with the increase of TVR of porous specimens at later healing ages. It lies in that specimens with low TVR are blocked by electrodepos- its gradually, and so the electrodeposition rate decr