外文翻譯--再生混凝土的基本力學(xué)性能和顯微結(jié)構(gòu)研究（英文）

1、104 Vol.28 No.1 CHEN Baofan: Basic Mechanical Properties and Microstructural Analysis...Basic Mechanical Properties and Microstructural Analysis of Recycled ConcreteCHEN Baofan1, 2(1. College of Civil Engineering, Limi

2、ng Vocational University, Quanzhou 362000, China; 2. Applied Technology Engineering Center of Fujian Provincial High Education for Practical Chemical Material, Liming Vocational University, Quanzhou 362000, China)Abstra

3、ct: The regeneration aggregate, natural aggregate, P?O42.5 R Portland cement, coal fly ash, and slag powders S95 graining blast furnace, homemade P(AA-co-MA)/PEG carboxylic acid water reducing agent, were used together

4、 with recycled concrete aggregate in different regeneration rates to prepare recycled concrete (RC). The influences of different renewable aggregate ratios on the basic RC replacement mechanical properties, uniaxial co

5、mpression stress and strain curve, and the elastic modulus and rebound value were investigated.The results show that RC mechanical properties decreases with renewable aggregate replacement rate increasing. The prolonga

6、tion can reduce the reduced span. Key words: recycled concrete (RC); regeneration aggregate replacement rate; mechanical properties; uniaxial compression stress©Wuhan University of Technology and SpringerVerlag Be

7、rlin Heidelberg 2013 (Received: Nov. 05, 2011; Accepted: Aug.13, 2012) CHEN Baofan(陳寶璠): Assoc. Prof.; E-mail: chenbaofan2008 @163.comFunded by Fujian Education Department (Nos.JA11329, JA12412), and Quanzhou (Fujian) Te

8、chnology Research and Development Program (No.2010G7)DOI 10.1007/s11595-013-0649-x1 IntroductionNow a large amount of waste concrete has been produced. The amount of waste concrete not only takes up precious land re

9、sources, but also causes serious environmental and social problems. The most effective way to dispose the waste concrete is to recycle and reuse the abandoned concrete, i e, the application of recycled concrete (RC)

10、[1]. The mechanical properties of the RC play a key role in the application of RC technology. Many tests have been done on the mechanical properties of the RC by different scholars [2-5]. Some researchers [6-17], hav

11、e focused on the analysis of the RC compressive strength, uniaxial tension performance, and the flexural strength angle, et al. More comprehensive research on mechanical properties is lacked. Mechanical property test

12、s, including cubic compressive strength, tensile strength and flexural strength, uniaxial compression stress and strain curve, the elastic modulus and rebound value of comprehensive test are carried out in this paper.

13、 Additionally, the RC microstructure is discussed. The research played a very important role on the application of RC.2 Materials and methods2.1 Raw materials Cement (C): P?O 42.5 R cement; Fly ash (FA): II grade f

14、ly ash; Granular blast furnace slag powder (GBFS): S95 level; Fine aggregates (S): 40% desalination sand and 60% made sand; Natural coarse aggregates (NA): ordinary gravel with particle sizes ranging from 5 to 25 mm;

15、 Superplasticizer (Super- effective plasticizer): P(AA-co-MA)/PEG poly- carboxylic acid plasticizer; Recycled coarse aggregates (RCA): Abandoned concrete with strength grade of C30 as the experimental target. After two

16、 broken processing, the particle size ranged from 5 to 10 mm; Water: Industrial water.The main preperties are list in Tables1-7. 2.2 Test material proportions To study the basic mechanical properties, the RC, RC-0,

17、RC-25, RC-50, RC-85, and RC-100 series were introduced. The proportions of concrete in these series were based on the zero replacement ratio. The test strength was C25, and the water-binder ratio, W/B (where B is the

18、 cement material dosage of C, FA, or GBFS) was 0.47. The FA and GBFS were mixed and the total number of them was no more than 25%. The 106 Vol.28 No.1 CHEN Baofan: Basic Mechanical Properties and Microstructural Analy

19、sis...The specimens were 150 mm × 150 mm × 150 mm and 150 mm × 150 mm × 300 mm, respectively for cubic and uniaxial compression tests. The specimen size for tensile and flexural strength test was 1

20、50 mm × 150 mm. White concrete with three layers of molding were put on the vibration bench. After 1 d of stripping, the molding was placed in a curing room at 20± 3 ℃ and relative humidity above 90%. 2.3

21、Test methods RC specimens compressive strength test was performed according to “The Ordinary Concrete Mechanics Performance Test Method“(GB 50081-2002). Specimens are wiped clean, and placed under pressure plates. Ad

22、d lotus should be continuous and even, and add lotus speed is 0.5-1.0 MPa/s. Record the maximum load F (N), and the bearing pressure fcu of RC can be calculated:(1)where f is the bearing pressure of RC test specimen,

23、 MPa; A is the bearing area of RC test specimen, mm 2. RC specimens uniaxial tensile strength test was performed: according to “The Ordinary Concrete Mechanics Performance Test Method “(GB 50081-2002). Body specimens

24、 (150 mm × 150 mm × 450 mm) were on both ends of the steel plate. In order to reflect the regeneration of the concrete uniaxial tensile properties, specimens were without leave gaps. Record the maximum load

25、 F(N), and the compressive strength of concrete samples ft can be calculated:(2)RC specimens flexural strength test was performed according to “ The Ordinary Concrete Mechanics Performance Test Method “(GB 50081-200

26、2). Specimens (150 mm × 150 mm × 550 mm)is firm. Add lotus should be continuous and even, and add lotus speed is 0.05 MPa/s. Record load F (N), and the flexural strength ff can be calculaed:(3)where L is spa

27、ce between adminiculas, mm; b is section width of RC test specimen, mm; h is section width of RC test specimen, mm. According to “The Rebound Method of Detection Concrete Compressive Strength Technical Regulations“ (

28、JGJ/T 23-2001), three cubes (150 mm × 150 mm × 150 mm) were obtained:(4)where R is the rebound value; ma is the average value of non-level statei; i is the measuring point. And then find the corresponding lev

29、el of detecting state rebound value:Rm=Rma+Rsa (5)where m is the calculation value of non-level state; sa is the corrected value of non-level state. SEM were used for the microstructure

30、analysis.3 Results and discussion3.1 Basic mechanical properties of the RCAt a water-binder ratio of 0.47, the mechanical properties of renewable aggregates with different replacement ratios changed with age, as show