专业英语论文.docx

1、专业英语论文Low noise asphalt pavementBy *experiment class of Civil engineeringKeywords: low noise; Asphalt pavement; Mix; Mix designAbstract: In order to study low noise asphalt pavement mixture gradation design method, using the aggregate gradation design and optimum asphalt content as low noise asphalt

2、 pavement mix design two major design index, adopt the token method to determine aggregate gradation design, by the means of the theoretical calculation, flow test and asphalt drop test analysis, to determine the asphalt .The best mixture asphalt content. The results show that the token method get m

3、ixture voids and target void ratio has a good linear correlation, the flow test method to determine the optimum asphalt content of asphalt mixture, more accords with the practice of engineering and easy to generalize. Low noise asphalt mixture due to different from ordinary asphalt mixture, so cant

4、use ordinary asphalt mixture design method to study. Asphalt mix design, including aggregate gradation design and optimum asphalt content determine two content, and In China there is no mature experience. The design method, it is the study of the main problems need to be solved.Introduction:In recen

5、t ten years, thanks to the government increased the transportation infrastructure construction force and active investment policy, Chinas rapid development of highway construction, especially the main national highway construction has made great progress, road network is the total size and overall t

6、echnical level have increased greatly. By the end of 2000, the national highway mileage understanding 167. 980000 kilometers, of which grade highway 131. 590000 kilometers,The national road network density up to 17. 5 km/hundred square kilometers. The rapid development of highway construction, incre

7、ase transport capacity, promote regional economic rapid development speed, but also to the surrounding environment caused by a certain degree of pollution damage, traffic noise is one of the major pollution.Traffic noise as a kind of noise pollution, the residents of the interference in many countri

8、es has more than other forms of noise pollution.In France, 80% of those surveyed think noise pollution in daily life the biggest cause of interference, half of which people think that traffic noise is the main noise source. Similarly, in Beijing a survey also showed that the traffic noise pollution

9、complaints accounted for more than 55% of the total noise complaints. The traffic noise pollution economic loss is difficult to accurately measure, in 1996 the European commission, says a report from the European Union countries home every year because of the loss caused by traffic noise estimates o

10、f GDP 0. 2% 2%.In China, with the rapid development of national economy, the appearance of a large number of new passenger and cargo traffic volume, the domestic various operating vehicles and private car society has doubled to 1990 as an example is 632. 980000 quantity, to 1999 increase to 1986. 82

11、0000 quantity. The amount of car number multiplied, plus the road mileage increase, level enhancement and the improvement of the roads, certainly will bring road traffic of rapid growth, if not take effective measures, will cause the deterioration of the road noise pollution. In urban road traffic n

12、oise as an example, according to the China environmental conditions bulletin of the data, the urban road traffic noise pollution in 2000 compared with 1999 shows ascendant trend, table 1-1 is the national 200 key city traffic noise level.Table 1-1 in 1999 and 2000, national key urban traffic noise m

13、onitoring results comparisonyearpollution levelHeavy pollution（%）Moderate pollution（%）Light pollution（%）Good（%）19995. 28. 527. 35920008. 922. 453. 315. 4In general speaking, the key urban road traffic noise pollution in mild basic state, individual main line both sides even overweight strict heavy.

14、Beijings fourth ring road (highway standard) as an example, 2001 years of noise test results show that the average noise between day for 74. 3 77. 6 dB (A) between, night for 73. 8 77 dB (A) between. Much more than national standard day room 70 dB (A), night 55 dB (A) between the highest limit.Sourc

15、e to distant spread, acoustic energy with diffusion distance increases; decay rate and the shape of the wave front. However, if there is a source close to the surface, it would happen, and then the surface of the sound wave reflection appear additional sound diffusion. This kind of additional sound

16、diffusion effect in the automobile tire noise diffusion process is very outstanding. When close to the source of the reflecting surface is porous structure, additional sound diffusion effect will occur in the table surface. At this time, the distance to receive the sound pressure level is direct dif

17、fusion acoustic and reflection of the sound wave superposition effect. When the acoustic constitute the main part of the phase difference for 180 degrees occurs when the destruction of the sound wave interference, synthetic pressure decline. Tire noise in the reflection surface diffusion, damage int

18、erference occurred in high frequency sound waves part. This is because the tire noise source close to the surface (usually less than road 5 cm), sound waves and acoustic reflection of the phase difference is small, damage interference will only be possible in small wavelength acoustic (i.e., more th

19、an 8000 Hertz high frequency noise). However, tire noise in pore surface diffusion propagation, due to the additional phase change, damage in low frequency interference (general for 800 1000 hz) acoustic part occurred. And this part of the sound wave is the tire noise is the main component of energy

20、. In addition, the pore of the pavement structure also can absorb part of the tire noise. Comprehensive the above discusses, car tire noise source mainly includes two kinds of working mechanism: 1) tire and road surface in contact closed air compression and suck out; 2) road table bump make tires pr

21、oduce vibration. Tire noise is spread in the reflection of sound waves superposition and damage mechanism of interference, etc.Design of the basic conditionsFunctional prerequisiteLow noise asphalt pavement, with other pavement type differences, its has a sound absorption property and water permeabi

22、lity and other special functions. In addition, the use of mix in addition to should have a specific target function outside, still have to meet the requirements of the durability, which means the functionality and durability, and at the same time depends on the gap mixture, so in order to ensure fun

23、ctionality and durability are to reach the required standard, must be carefully selected mixing of voids.The asphalt amount, mixture of void fraction and the functional and durable sex relation model as shown in figure 1 shows. From the chart that the void fraction and the functional and durable sex

24、 relationship is instead, but there are both satisfied range. In the mix fit than design, first make sure the common voids range is very important, note meaning common range by the lower limit of functional, limit the durability of the decision. About function sex, mainly is the sound absorption pro

25、perties and water permeability, etc.; Durability, basically be the deformation resistance and abrasion performance and mechanical properties.Practical necessary conditionsLow noise asphalt mixture, with ordinary asphalt mixture phase comparison, in resistance to peel resistance and durability is bad

26、, which requires the voids in the meet functional and resistance to long sex at the same time, other performance should not have practical problems.In order to get practical mixture, control the amount of asphalt add how much, is very important. In the permitted gap rate range and do not produce wra

27、pping covering bad and flush phenomenon at the same time, to mix applied forces, get as much as possible to ensure the stability of the aggregate qualitative between cohesive force. In this way the adding amount of decision asphalt is quite necessary.Asphalt quantity to be added, void ratio and the

28、relationship between the cohesive force between aggregate, as shown in figure 2 shows. When the amount of asphalt in the A1, asphalt, aggregate wrapped by the completely between bonding force extreme low. With the increase of adding amount of asphalt, asphalt, aggregate wrapped overlying become good

29、 between cohesive force is getting higher, but a smaller voids, when achieved in A2, due to the asphalt surplus, to generate flush phenomenon at the same time, the aggregate between cohesive force is also constantly decrease until doesnt work so far.Thus it can be seen, low noise asphalt mixture asp

30、halt in addition quantity, it is graph physical line represents A1 - A2 range. But in order to ensure the stability of the mixture, it is necessary to set that aggregate it can improve the cohesive force between the asphalt adding amount of A3. Therefore, it is considered that the adding amount of a

31、sphalt in A3 - A2 range, can get practical mixture character. The lower limit of the aggregate between cohesive force, and upper limit of the produce flush now like to determine the threshold quantity. It is concluded that in low noise design of asphalt mixture, the first set must be set at the same

32、 time satisfy the functional and durability of the void fraction, and then determine can guarantee the voidage of aggregate gradation, and press the aggregate gradation determine the adding amount of asphalt.Design methodexternal factors setTo mix with the design, in addition to internal factors should be considered mixture outside, also want to consider the use place weather conditions, traffic and road width, etc. Cases such as cold snow area and hope to get abrasion resistance road area, it is necessary to consider reduce gap or use high cohesive force of the asphalt. In add