沥青与沥青混合料课程论文

1、Asphalt Binders and Asphalt Mixtures沥青与沥青混合料Course Paper课程论文Penetration Index of asphalt bindersName:Student Number:Class:Dec 2012ABSTRACTThe asphalt penetration index is the concept defined by the famous Netherlands Research asphalt scholar J.Ph.Pfeiffer and Van Doormaal in 1936, published in the J

2、ournal of the Institute of Petroleum Technology experts entitled The Rheological Properties of the Asphaltic Bitumen.Penetration index PI is used to describe the bitumen temperature sensitivity indicators. Penetration asphalt quality indicators. The higher the PI,the lower the temperature susceptibi

3、lity,vice versa.Shows that the asphalt degree of hardness and the consistency and the ability to resist shear failure, reflecting the indicators of the relative viscosity of the bitumen under certain conditions. Within 25 C and 5 seconds, under a load of 100 grams, the standard vertical penetration

4、depth of the asphalt specimen for penetrometer, in units of 1/10 mm.The road asphalt penetration grading system is determined according to the size of the asphalt penetration asphalt adapt to climate conditions and load conditions. Penetration grading system of the main people familiar pull (ductili

5、ty), bar (penetration), fall (softening point), supplemented purity indicators solubility of the safety indicators flash point of the asphalt, bitumen, asphalt the aging performance indicators thin film oven test and the crude oil used in the production of asphalt constraint index wax content, etc.,

6、 constitutes the bitumen has a penetration grading system.Normally PI=-1.0 to+1.0.Penetration index is an important indicator to determine the level of asphalt.Key words:asphalt;penetration index;penetration; temperature sensitivityINSTRUCTIONThe most important material properties of the asphalt, in

7、cluding rheological properties, interface properties and resistance to aging characteristics, etc.By the time, temperature, load, various media, the role of its performance characteristics depending on the chemical composition and physical properties, and also and asphaltthe colloidal structure type

8、s are closely related.Penetration index is used to describe the the asphalt temperature sensitivity and colloidal structure type an empirical parameters.Penetration grading system, asphalt penetration test is the standard method for the determination of asphalt consistency. The 25 penetrometry given

9、 consistency close to the annual average temperature of asphalt, the results show that the asphalt is dropped to 20 or less at 25 C a needle into, there will be a serious pavement cracking, when the bitumen has a penetration greater than 30, having a high cracking resistance. Asphalt ductility and i

10、ts associated road performance, studies have shown that the delay is less than 13 5cm, road temperature shrinkage crack to a substantial increase in. Another study confirmed when the bitumen has a penetration degree of 30-50, the same pitch, the ductility than the ductility of the penetrometer use p

11、erformance is poor. Also found more and more evidence that the recovery of bitumen ductility test is an important method to determine the asphalt through the pavement process. The nature of the reclaimed asphalt pavement of U.S. Highway 53 found that the ductility decreased to 16 C when the severe p

12、henomenon of loose 3cm or less, the cold weather will occur. Shows that the ductility of the asphalt, especially asphalt, the low-temperature ductility, can reflect the cracking resistance of asphalt.The greater the penetration, the higher the asphalt label, such as No. 70 asphalt penetration 70,90

13、No. asphalt penetration is 90 different the different climate Select label Southern labeled low northern label high point.The larger the penetration, the asphalt is softer, low softening point, high-temperature performance with the increase in penetrometry reduced, low temperature performance conver

14、sely.Even if many of the indicators of the penetration grading system is empirical and conditions, but because of the methods and the use of instruments is relatively simple, easy to popularize, to some extent, to meet the requirements of asphalt quality control, is currently the United States, the

15、European Union, Australia, Japan and other countries, the current standard remains the penetration grading system. China road asphalt grading system, is developed according to the specific circumstances of the country on the basis of the above penetration grading system, and can basically meet the a

16、sphalt quality control, especially 15 C ductility greater than 100 and wax content technical indicators, less than 3% of the effective realization of the limitations of the production of asphalt, crude oil, and to ensure that the potential quality of the asphalt.Penetration index usually as an expre

17、ssion of the low penetration of the oxidized asphalt and roofing asphalt, moisture-proof waterproof asphalt, high softening point asphalt temperature susceptibility index.Penetration indicators are included in only a few countries of the road asphalt quality standards: a) Russia, penetration - softe

18、ning point calculations to strike PI values; penetration index b) the European Union, as a selective index, Belgium,penetration index in Spain, the Netherlands, Switzerland and Greece, and other EU countries not using the penetration index, also penetration, softening point calculation strike penetr

19、ation index.Ministry of Transport of the Peoples Republic of China(MOT) had several of our production asphalt detailed the use of performance comparison study.As the asphalt temperature susceptibility is more reasonable to think that using the penetration index, inflated the illusion and high wax co

20、ntent of asphalt softening point the penetration index should not be used penetration, softening point calculation strike thepenetration should be used, the temperature regression methods to strike.RESEARCH OBJECTIVESThe road asphalt penetration index is drawn through the asphalt penetration test. S

21、tandard test conditions of 25 C, Load 100g penetration time 5s to 0.1mm.MaterialsA penetrometer is needed in this study. The penetrometer needs to ensure the vertical movement of the needle and needle rod in the case of no significant friction, and the depth of penetration of the needle to the neare

22、st 0.1 mm. The total mass of the needle and the needle connecting rod assembly 50g 0.05g, the attached 50g 0.05g weight one, when testing the total mass should be at 100 0.05g. The instrument has a platform for placing a flat-bottomed glass insulation dish, and level adjusting means, the needle rod

23、shall be perpendicular with the platform. The instrument has a needle rod brake button, so that the the needle rod can free-fall. The instrument also has a freely rotating and adjusting the distance of the cantilever, and its end portion side of the small mirror or spotlight bubble, in order to obse

24、rve the conditions of exposure of the tip and the sample surface.Penetration value is a displacement tables determination, and can automatically display or record, and should calibrate the accuracy of the automatic device very offen.The Standard type probe is made of a hardened and tempered stainles

25、s steel. Rockwell hardness HRC54-60,surface roughness Ra0.2m0.3m.The total mass of the needle and the needle bar 2.5g 0.05g. Needle bar should print the number sign, needle box (cylinder) shall be provided with a fixing device to avoid the collision point of a needle, each needle must be accompanied

26、 by a check list of the metering sector and periodic inspection. A cylindrical containing dish constituded by metal production with a flat bottom is needed.The small dish inside diameter of 55mm, depth 35mm (applicable to needle people degree less than 200);the big dish inner diameter 70mm, depth 45

27、mm (suitable for needle degrees 200 to 50); degree greater than 350 specimens of needle people need to use special sample dish, its depth of not less than 60mm, the sample volume is not less than125mL Thermostat tank capacity of not less than 10L, temperature control accuracy of 0.1 C.Sink shall be

28、provided along the hole of the shelf, located below the surface shall not be less than 100mm from the sink bottom shall not be less than 50 mm. A flat-bottomed glass dish capacity of not less than 1L, and a depth of not less than 80mm.Equipped with a stainless steel tripod, make the sample dishs sta

29、ble. Thermometer: 0 50, the indexing of 0.1. The lid of the sample dish: flat glass, diameter not less than the size of the opening of the sample dish. Trichlorethylene as a solvent.Something else such as EAF or sand bath, Asbestos Network, Metal pot or porcelain crucible etc is needed.Penetration t

30、estThe test methods are as follows. Prepare the sample as method T0602. Test requirements thermostatic water bath adjusted to the requirements of the test temperature of 25 or 15, 30, remained stable. Sample injection sample dishs, sample height should exceed the expected value of the needle people

31、10mm, and covered with loaded sample pan lid, to prevent falling into the dust.Containing sample loading pans to cool room temperature 15-30 1h-1.5h (small sample dish), 1.5h-2h ( big sample dish) or 2h-2.5h (special sample dish)shift people to maintain the required test temperature at 0.1 constant

32、temperature water bath lh-1.5h (small sample dish), 1.5h-2h (large sample dish) or 2h-2.5h (special sample dish). Adjust the penetrometer to make it level.Check the needle rod and rail, to confirm the anhydrous and no other foreign objects, no significant friction. Trichlorethylene or other solvents

33、 to clean the standard needle and drying. The standard needle is inserted into the needle rod tight with screws. Test conditions, coupled with the additional weight.Then Remove reached thermostat containing sample dish, and transferred into the water temperature is controlled at the test temperature

34、 0.1 (available water in the thermostatic water bath) in a flat-bottomed glass dish on the tripod, the depth of the water layer above the sample surface is not less than 10mm. And a sample of flat glass dish in penetration instrument platform. Slowly put down the needle rod, put in place of the mirr

35、or or light reflection observation, make the tip and the sample surface contact. Pull down the scale of the rod, making it the top of the connecting rod with the needle gently contact, adjust scale or depth indicator pointer make it instructions for the zero. Press the button, the timing with the st

36、andard needle drop penetration sample began at the same time, to automatically stop when the 5s. Pull down the the dial lever is in contact with the top of the needle rod to read dial pointer or displacement indicator readings, accurate to 0.5 (0.lmm). Same specimen parallel test for at least 3 time

37、s, between each test point and the distance to the edge with the a sample dish should be less than 10mm.After each test should be equipped with a flat-bottomed glass dish sample dish put heated water tank, the water temperature in a flat-bottomed glass dish to keep the test temperature.Each test sho

38、uld be replaced by a clean standard needle or remove the standard needle with trichlorethylene solvent cotton or cloth moistened with clean with a dry cotton cloth to dry. Determination of the needle people asphalt samples greater than 200 degrees, at least three standard needle each test after the

39、needle is left in the sample, up to three parallel tests completed to the standard needle is then removed.DIAGRAM 1Penetration Test Schematic DiagramPenetration index calculationThere are typically three penetration index calculation methods. First one,traditional definition:The second,using Nomogra

40、m.The third is using the penetration test results to calculate PI.And here we introduce this penetration calculation method.Penetration value tested under different temperature logarithmic, make y=lgP,x=T，according the linear relationship between penetration logarithmic in formulas（1）and temprature，

41、make linear regression of y=a+bxlinear equation with one unknown,then find out penetration temperature index. (1)In formulas:Tdifferent test tempratures，the corresponding temperature penetration for P;Kconstant term a of the regression equation;equal to coefficient b of the regression equation.By eq

42、uation (1) regression must correlation test, linear regression correlation coefficient R shall not be less than 0.997 (95% confidence), otherwise the test invalid.And according to equation (2) to determine the asphalt penetration index PI, and denoted by .= (2)DISCUSSIONSThe temperature sensitivity

43、is the most important one of the material properties of the asphalt.PI is a important indicator of the asphalt used to describe the temperature sensitivity of an empirical parameter.Therefore the PI is widely used in the determination of the asphalt nature.Penetration index derived from the penetrat

44、ion index defined above experimental method, let me see a lot of drawbacks and unreasonable.The temperature sensitivity into the bitumen quality standard is reasonable.But using the method of penetration, temperature regression to strike PI obvious exist errors.These errors first from penetration me

45、asurements,the error of the instrument, the readings.For exampl:the time of asphalt placed make changes to the penetration, and the entire experimental process must require a certain amount of time to place asphalt.The sample in the sample preparation process, whether there are bubbles, the cooling

46、in the air when the room temperature.The time in the air, in the cooling of the water affect the results of the penetration. The edge of the test conditions, such as the test temperature, the weight by weight, the test time, the distance between the needle and the needle or the needle and the sample

47、 dish also affects the error penetrometry. Not difficult to come the above test conditions may exist following impacts.Laboratory environment at lower temperatures, asphalt specimen cooling is relatively full, the measured value of the penetration is low; cooling at room temperature long time, aspha

48、lt specimen cooling is relatively full, the measured value of the penetration is low; thermostat water bath longer, the sample cooled more sufficiently low measured value of the penetration.;Bubbles into the asphalt sample the penetration measurement results is too large.Then there is a error from c

49、alculation method,Mathematical methods on penetration - temperature regression equation PI values inherent to large errors. According to the the PI calculation formula can be seen, the error sources of the PI is only one, that is the penetration degree. And the calculation method further magnified p

50、enetration error.The value of PI is directly related with the choice of the degree of penetration testing temperature and the number of Penetration - Temperature calculation points. Determination of penetration is a strict test. Its calculation is influenced by many factors. Reaction to the PI calcu

51、lation results on the impact of these factors will double.Temperature sensitive with PI expression is based on a linear relationship exists between the logarithm of the penetration and the temperature. However, studies have shown that lgP in a wide temperature range, and lgP and T curve related, rat

52、her than straight,.Therefore, various asphalt samples obtained PI by the above method can not reflect it in the use temperature range of the entire pavement temperature sensitivity.There are studies showed that the same kind of asphalt under different temperature ranges PI value is divergent.So, for

53、 the same kind of asphalt, the penetration data regression deviation produced using different temperatures would be considerable.Thus, PI is closely related to the range of the temperature interval taken. PI of the same asphalt in different temperature ranges characterize asphalt temperature sensiti

54、vity , the asphalt in relationship between lgP and T under different temperature range not given value. The reason is that the road asphalt is a viscoelastic material, the rheological properties of the asphalt is different in a different temperature range, but also for the different sources of aspha

55、lt, because of its chemical composition and different colloidal structures, the mechanical properties of the asphalt is not the same with the temperature response. Since the bitumen colloidal morphology will change under different temperature ranges, so its temperature sensitivity also will change.

56、Used to characterize asphalt temperature sensitivity of PI from the asphalt viscosity changes within a fairly narrow temperature range, and simplified to a linear relationship, the inference will be generated outside the region of the excessive temperature deviation. Even in a narrow temperature int

57、erval in lgP and T linear relationship,by penetration measurement result of the error in the calculation formula is amplified many, and ultimately lead to the PI values of a large deviation.Standard Test Method using penetration - temperature multi-point regression method will greatly increase the t

58、he penetration measurement equipment requirements, especially the thermostatic device. Increased workload, labor costs, and extend the analysis time, inconvenience asphalt production quality control and the asphalt construction quality control. In addition, due to the presence of measurement error in the PI, the PI data of the determination will be d