PG 76-10 Bitumen
WHAT IS PG BITUMEN?
Considering that bitumen is known as the most important component of road pavement and asphalt, and if this bitumen does not have proper quality and performance, it will have a direct effect on the quality of asphalt. Recently, instead of producing viscosity grade bitumen and penetration grade bitumen, PG bitumen is used in asphalt production. In PG bitumens, the classification is based on understanding the behavior of the bitumen and its functional characteristics, so that in this classification, different characteristics against cracking and deformation due to cold and heat and fatigue and predicting the hardening of the bitumen at the production site and factory in It is taken into consideration when preparing asphalt. Also, the amount of traffic and the passage of time and speed of loading on the road are considered. The difference between PG 76-10 bitumens and other mentioned bitumens is in the actual conditions used in it, so that for the optimal use of bitumen, different atmospheric conditions are taken into account, and especially the environmental climate is special.
As mentioned, in this method, the grading of road construction bitumen is based on the prediction of its performance on the road, so that it is classified into different groups based on the properties of the bitumen in real conditions, such as types of weather, which are based on the precise behavior of its functional properties. For example, in the previous classifications, the degree of penetration and the viscosity value of the penetration and plasticity tests do not affect the performance of bitumen, while in functional bitumen (PG 76-10), the physical properties of engineering principles are directly related to the performance of bitumen, and in the previous classification, the test It is done at a standard and specific temperature. Without referring to the actual conditions of the asphalt environment, but in PG bitumens, the basis of the tests is variable according to the test conditions. Also, bitumen aging tests are performed in the short term, but in PG bitumens, these tests are for a long time and also during operation. And it is done after mixing and producing asphalt.
PG bitumens are graded based on performance at different temperatures, so that the highest and lowest asphalt temperatures are already calculated and the best bitumen at that temperature is suggested. In this method, bitumen is classified based on performance characteristics in different weather conditions so that it can limit the permanent change of bitumen and its failure due to fatigue and cracking at low temperatures. For example, it is designed for a bitumen in average weather conditions for seven consecutive days from 52 degrees Celsius above zero to 40 degrees Celsius below zero, it can be used at this temperature. In this category, any type of bitumen with two positive numbers A negative number is defined in which a positive number corresponds to the average of seven consecutive days of the highest pavement temperature in the summer season and a negative number is the minimum pavement temperature in seven consecutive days of the winter season in degrees Celsius.
Therefore, the positive number indicates the maximum tolerable temperature of the bitumen, and the negative number indicates the minimum tolerable temperature, although sometimes by users, this classification can be equated with the classification based on penetration grade bitumens, such as 70 bitumen. 60/60 with a penetration degree of 64-70 is equivalent to 22-64 PG bitumen and 85-100 bitumen with a penetration degree of 95 is equivalent to 58-22 PG bitumen, but if the bitumen used is 22-58 PG bitumen, it has the same performance as 85-100 bitumen. But it is a little looser, which is suitable for relatively cold regions.
PERFORMANCE GRADE BITUMEN PG 76-10
The performance grade of bitumen or PG is the latest standard in the world. This method is a relatively new method that classifies bitumen based on the temperature conditions of different regions. In this method, the mechanical properties of bitumen are examined from completely scientific methods. In this method, a temperature range is assigned to the bitumen, and the consumer can choose the appropriate bitumen according to his desired location.Today, for polymer modified bitumen and pure bitumen according to the standard, a performance grade or PG is defined according to temperature and environmental conditions. The wider range or range of PG 76-10 of a compound means more desirable properties and higher resistance. By launching and installing the most advanced SHARP devices, this company is able to offer bitumen to its customers in a new functional way. Different climate zoning has been done and it specifies what type of bitumen is suitable for each region in the country.
EXPERT REVIEW OF PG BITUMEN
The performance grade of bitumen or PG 76-10 is the latest standard of the world. This method is a relatively new method that classifies bitumen based on the temperature conditions of different regions. In this method, the mechanical properties of bitumen are examined from completely scientific methods. In this method, a temperature range is assigned to the bitumen, and the consumer can choose the appropriate bitumen according to his desired location. Today, for polymer modified bitumen and pure bitumen according to the standard, a performance grade or PG is defined according to temperature and environmental conditions. The wider range or range of PG 76-10 of a compound means more desirable properties and higher resistance. RAHA Oil Company is able to offer bitumen to its customers in a new functional way by setting up and installing the most advanced SHARP devices. Climate zoning of Iran has been done for the first time by this company and it specifies what type of bitumen is suitable for each region in the country.
| High performance temperatures | Low temperature degrees of efficiency |
|---|---|
| PG 46 | -34, -40, -46 |
| PG 52 | -10, -16, -22, -28, -34, -40, -46 |
| PG 58 | -10, -16, -22, -28, -34, -40 |
| PG 64 | -10, -16, -22, -28, -34, -40 |
| PG 70 | -10, -16, -22, -28, -34, -40 |
| PG 76 | -10, -16, -22, -28, -34 |
| PG 82 | -10, -16, -22, -28, -34 |
FUNCTIONAL CLASSIFICATION BITUMEN PG
In this way, bitumen is classified based on performance characteristics in different environmental conditions. The specifications are defined in such a way as to limit the potential for permanent bitumen change and failure due to fatigue and cracking at low temperatures.
For example, a bitumen is designed in such a way that it can be used in environmental conditions with an average seven-day maximum temperature of 52 and a minimum temperature of -40.
Types of emulsion bitumen in terms of electric charge:
- Decreased thermal sensitivity
- Increasing elasticity
- Increasing the service range in terms of temperature
- Increased tensile strength
- Increase the service life
- Reducing the amount of road damage
A functional classification for bitumen selection is developed by SHRP. In this classification, which is based on understanding the behavior of bitumen and its functional characteristics, with the characteristics of resistance to deformations, resistance to cracking due to cold, resistance to cracking due to fatigue, predicting how bitumen hardens in Asphalt factory and when preparing the asphalt mixture, how the bitumen hardens due to the passage of time and with the tests determined in the specifications, has been evaluated and the appropriate bitumen according to the temperature of the project site, the amount of traffic, the speed of loading and The geographical location is selected.
Each type of bitumen is characterized by two positive and negative numbers, the positive number corresponding to the average seven consecutive days of the highest pavement temperature and the negative number, the minimum pavement temperature in degrees Celsius. PG 76-10 stands for performance grade. This classification is used to investigate the performance of bitumens in different weather conditions. Polymers help us to change the performance of bitumens according to the weather conditions of the place of use.
EQUIVALENCE OF BITUMENS
As various studies and tests on the bitumens produced in the country show, it can be said that these bitumens do not have unacceptable fluctuations and changes in the amount of their penetration degree parameter, and generally this parameter is within the standard range for the said bitumens. Therefore, the bitumens produced in the country’s refineries can be classified into two standard categories: 60/70 and 85/100. Research shows that 60/70 bitumen produced in Middle East refineries with a penetration degree of 64.7 is equivalent to PG64-22 bitumen in the SHRP classification, and 85/100 bitumen produced in Middle East refineries with a penetration degree of 95 is equivalent to PG58-22 bitumen in It will have SHRP rating.
PG bitumen named PG6422 and PG6410 performs almost the same function as bitumen 6070. The meaning of the numbers in front of PG, such as 6422, is that the bitumen performs well from -22 to +64 degrees Celsius. The conversion of PG bitumen is similar to the conversion of bitumen 6070, but if the bitumen used is PG5822, it will have the same performance as bitumen 85100 and it will be a little looser.
DESCRIPTION OF TESTS RELATED TO FUNCTIONAL GRADING METHOD
1- Dynamic shear rheometer test (DSR): Because bitumen behavior depends on temperature and duration of loading, optimal testing for bitumen should consider both factors. Dynamic shear test evaluates both temperature and time effects and measures rheological properties (phase difference angle and shear modulus) at medium and high temperatures.
2- Bending beam rheometer test (BBR): Conducting bitumen hardness test at low temperature by dynamic shear resistance measuring rheometer is not completely reliable. Therefore, SHRP researchers have prepared a bending beam rheometer to accurately evaluate the properties of bitumen at low pavement temperatures. Two tests, dynamic shear and beam bending, predict the hardness behavior of bitumen in a wide range of temperature changes. This test measures the amount of drop and rise or creep of bitumen under constant load. The test temperature depends on the lowest operating temperature of the pavement, where bitumen behaves more like an elastic solid. This test is performed on bituminous materials that have been aged in both the rotating thin glaze test and the accelerated aging chamber test. Therefore, this test measures the performance characteristics of bitumen that has been subjected to hot mixing and aging during the service period.
3- Direct tension test (DDT): Although hardness can be used to estimate failure or strength, but for some materials (especially modified bitumen) the relationship between hardness and strength properties is not well known. Therefore, regarding the measurement of strength and breaking strain (ability versus tension before breaking), another test called the direct tension test should be conducted. Bitumens that withstand significant elongation before breaking are called elastic, and those that break without much elongation are called brittle. It is important that bitumen is able to withstand minimum tension. Generally, harder bitumens are more brittle and softer bitumens are more elastic.
4- Rotating thin glaze test (RTFO): The cause of bitumen aging is the evaporation of its light oils and oxidation (reaction with ambient oxygen). During the production of hot asphalt and during its handling, bitumen is aged by both mechanisms due to high temperature and air flow. This test, which is described in ASTM-D 2872, models this aging and determines the amount of mass loss. Another purpose of this test is to provide aged bitumen for other tests of physical properties of SHRP. Reduction of the mass of volatile substances is a sign of aging that may occur in bitumen during mixing and manufacturing operations. For each type of adhesive, weight loss should not exceed 1%.
5- aging acceleration chamber test (PAV): Before the premium pavement, the long-term aging effects of bitumen were not considered in bitumen specifications. The accelerated aging chamber test was developed by SHRP to model the long-term aging of bitumen in asphalt mixtures. This test is described in AASHTO-PP1.
6- Rotational viscometer (RV) test: In AASHTO-TP 48, the standard test method for bitumen viscosity determination using rotational viscometer is stated. This test can be used for modified and unmodified bitumen. The rotational viscometer automatically determines the rotational viscosity by measuring the required torque and by maintaining the constant rotational speed of the rotating part that is immersed in the bitumen. In order for bitumen, especially modified bitumen, to be easily pumped and moved in hot mixing equipment, or easily mixed with stone materials at mixing temperature, their unaged hardness should be at most 3 Pa.s according to specifications and for all grades. Bitumen should be obtained at a temperature of 135 degrees Celsius.
THE PROCESS OF DETERMINING THE FUNCTIONAL INDEX
By using the results of SHRP tests, the performance grade of bitumen is determined. Bitumen performance grade (PG) has two numbers. The number on the left side shows the maximum tolerable temperature of bitumen and the number on the right which is negative shows the minimum tolerable temperature of bitumen.
PG XX YY
Graded bitumens are selected based on performance, according to the maximum and minimum temperature of the project site and its traffic volume. To determine the hottest and coldest temperature of each region, according to the data of the weather stations, the average temperature of the hottest and coldest days of the year is determined and finally the average of the data obtained for several consecutive years is calculated and by calculating the maximum and minimum temperature of the pavement with the relevant formula and with Using Table 4, bitumen functional grading is done based on the maximum and minimum surface temperature.
HOW TO CALCULATE THE MAXIMUM AND MINIMUN PAVEMENT TEMPERATURE
The obtained ambient temperatures are used to calculate the upper and lower limit temperatures of the pavement. The maximum pavement temperature is determined at a depth of 20 mm from the asphalt pavement surface and the minimum pavement temperature is determined at the pavement surface.
The following relationship is provided to determine the maximum surface temperature at a depth of 20 mm.
Tmax pav (20mm) = (T max air – 0.00618 Lat2 + 0.2289 Lat + 42.2) * (0.9545 ) -17.78
In this regard:
Tmax pav (20mm): The maximum pavement temperature at a depth of 20mm in degrees Celsius
Tmax air: the average air temperature of the seven hottest days of Salber in degrees Celsius
Lat: Latitude of the location of the pavement design in degrees
The lowest pavement temperature on the pavement surface is determined as a function of the lowest air temperature and based on the following relationship.
T min pav (surface) = 0.859*T min air + 1.7
In this regard :
T min pav (surface): the minimum pavement temperature on the surface in degrees Celsius
T min air: average air temperature of the coldest day of the year in degrees Celsius
In the SHRP method, for choosing the maximum and minimum temperature, designers are allowed to consider the confidence percentage using statistical charts. By definition, the confidence percentage is equal to the percentage probability that in any given year the actual temperature will not exceed the design temperature.
The average obtained from the temperatures of the hottest and coldest seven days of the year has a confidence percentage of 50%. To reach a confidence percentage of 98%, the standard deviation is used. To increase the accuracy in the calculations, LTPP Bind software is used, which is a program for determining the performance index (PG).
TECHNICAL DATASHEET OF SBS MODIFID BITUMEN PG 76-10
| Temperature: 25.0 o c | Humidity: 27 % | |||
|---|---|---|---|---|
| STANDARD RANGE | STANDARD RANGE | |||
| TEST | RESULT | MIN | MAX | TESTS METHOD |
| Binder | ||||
| Penetration @ 250C, 100gr, 5s, 0.1 mm | 47 | 40 | 70 | ASTM D5 |
| Elastic Recovery @ 250 C, IOCM Elongation (%) | 97 | 80 | - | ASTM D6084 |
| Softening point, o c | 83 | 70 | - | ASTM D36 |
| Separation Difference in Softening Point R&B, oc | 2.3 | - | 3 | ASTM D7173 |
| Ductility @ 25 0 C | 59 | 25 | - | ASTM Dl 13 |
| Dynamic Viscosity at 1350 C (Brookfield Viscomeler), Pa.s | 1.4 | - | 3 | ASTM D4402 |
| Penetration Index | 3.9 | 2.25 | 5.25 | ASTM D5 / D36 |
| Solubility in TCE (0/0) | 99.74 | 99 | - | ASTM D2042 |
| Flash Point Temp. oc | 338 | 245 | - | ASTM D92 |
| Orig. Dynamic Shear @ 76 0C / Kpa | 1.41 | 1 | - | ASTM D7175 |
| RTFO (D2872) | ||||
| Penetration of Residue (%) | 75 | 65 | - | ASTM D5 |
| Ductility @ 25 0 C | 51 | 15 | - | ASTM Dl 13 |
| Difference in Softening Point, o c | -7 | -10 | 5 | ASTM D36 |
| RTFO Percent Change Of Mass | 0.01 | - | 0.5 | ASTM D1754 |
| RTFO Dynamic shear @ 760 C / Kpa | 2.47 | 2.2 | - | ASTM D7175 |
| PAV (D6521) | ||||
| PAV - Dynamic Shear @ 37 0 C / Kpa | 264 | - | 5000 | ASTM D7175 |
| PAV Creep Stiffness @ 0 0C / Mpa | 28.26 | - | 300 | ASTM D6648 |
| m-Value @ 00 C / M a | 0.352 | 0.3 | - | ASTM D6648 |
For more information, please Contact our Sales Team.
