BITUMEN Penetration Grade
For building roads in a variety of environments, penetration grade bitumen is exceptional. The hardness and consistency of these bitumen grades are what give them their names, and they fall into a spectrum of grades from 30 to 120.
Determining bitumen's viability for usage with different building techniques and in various climates is the major objective of grading bitumen based on penetration.
PEN grades, commonly referred to as pavement grade bitumen, are categorized according to how deeply a specific laboratory needle can pierce them.
To determine how hard the bitumen is, a penetration test is conducted.
The tested bitumen is soft if the achieved results were high. It indicates that the needle has pierced farther.
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Lower numbers, on the other hand, demonstrate that the tested bitumen is strong/hard and states that the penetration depth is shallow. For example bitumen 60/70, the first number denotes the minimum penetration and the second number denotes the maximum penetration.
The grades of bitumen pen include 40/50, 60/70, 80/100, and 85/100.
Bitumen grades range from 85/100 is the softest, within 40/50 is the strongest/hardest.
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The term "30/40 bitumen" refers to bitumen with a penetration grade of between 30 and 40 mm at 25 degrees Celsius. A hard grade of Bitumen is 30/40. One of the Bitumen grades that is most frequently utilized for road construction in tropical locations is 30/40.
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Bitumen 30/40 is provided because of its high air blowing and penetration values, which make it a good choice for these regions' hot climates, which can be difficult for asphalt mixtures.
Through vacuum residue procedure a Bitumen grade 30/40 is produced in a refinery.
Hot mix asphalt is primarily produced using Bitumen Penetration Grades for the base and wearing courses of roads.
The average temperature of the area, the volume of traffic, and the kind of soil should all be considered while deciding between different grades of Bitumen penetration.
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The Bitumen becomes softer if the penetration grade is more. A lot softer than 40/50 is 80/100. For soils with a high particle density, such clay, soft bitumen is more suited. On the other hand, soils with low particle density respond better to high penetration graded Bitumen.
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Regarding Bitumen Penetration Grades, it's also essential to take the traffic load into account. When exposed to high traffic loads, Softer grades, such as 60/70 exhibit greater longevity. As a result, roads with heavy traffic loads are paved with lower grades.
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Examine test findings as well as other elements, including Penetration Grade, Flash Point, Softening Point, Ductility, and Specific Gravity, before utilizing Penetration Grade Bitumen.
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BITUMEN Penetration Grade SPECIFICATIONS
Bitumen Penetration Test: Method and Objective
Bitumen Penetration Test: Method and Objectives
In order to achieve the optimal performance for construction and other uses, bitumen must be graded according to its physical characteristics. Early in the 20th Century, a system for rating penetration was created. Using its penetration characteristic, bitumen penetration grade is categorized. Penetration tests are used to obtain penetration property.
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How do Penetration Test Work?
The purity and stability of pure bitumen, oxidized bitumen (also known as blown bitumen), and the leftover emulsion bitumen are all assessed using the penetration test. Tars and other very soft, low viscosity compounds cannot be tested for penetration.
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Bitumen is categorized using this test based on how hard it is. In addition to the penetration test, a softening point test is done to categorize oxidized bitumen.
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The needle is inserted into the bitumen vertically for 5 seconds at a temperature of 25 degrees Celsius to determine the penetration value. The penetration value, which is expressed in tenths of a millimeter, is the amount of needle movement. The bitumen grade increases in direct proportion to the needle's depth of penetration.
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The table below lists the characteristics and uses of various Penetration-Grade Bitumen.
What Justifies Bitumen Penetration Testing?
Using this technique, we may categorize bitumen according to its penetration value. This makes it easier to select the right bitumen in the ideal weather for secure road construction.
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In cold weather to avoid cracking. the soft bitumen which has higher penetration is used. In hot weather, The hard bitumen which has lesser penetration grade is used because due to heat it does not becomes soft.
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Application of Different Penetration Grades
Although the range of the bitumen's specified penetration value is 10 to 450, the range that is most frequently used for roads is 25 to 200. ​
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Norms for Bitumen Penetration
The following methods are the industry standards for bitumen penetration testing: ASTM D5, ASTM D946, and AASHTO M 20 (Penetration @ 25 °C).
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SABS 307 (Penetration @ 25 °C; Viscosity @ 60 °C after RTFOT)
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50 & 167IP 49
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ASTM D5
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ASTM D946 & AASHTO M 20 (Penetration @ 25 °C)
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EN 12591 (Penetration @ 25 °C)→NF EN; BS EN; DIN EN; etc.
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EN 1426
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DIN 52210
The Equipment, Parts and Test Procedures for the Bitumen Penetration Test
Penetration Test Components are:
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Water Bath: A container with at least 10 Liters of water that is 25 °C in temperature. The sample is submerged more than 100 Millimeters below the surface. Additionally, the supporting perforated shelf—which holds the sample—should be more than 50 Millimeters from the bath's bottom.
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Container Sample: An example of a container would be a compact, flat-bottomed, cylindrical dish made of glass or metal.
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Transfer Tray or Dish: It helps to keep the container submerged in the water bath when you use a transfer dish or tray.
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Needle for Penetration: Stainless steel needle for penetration that is cylindric and highly polished
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Stopwatch: An automatic timer with a 1/10-second precision.
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Thermometer: It displays temperatures between 0 to 44 °C.
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Penetrometer: The tool has a needle inside. It permits measuring the penetration by providing a weight of 100 grams with the least amount of friction and is used to release and lock the needle in any position. Accurate calibration is necessary.
Bitumen Penetration Test Methodology
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Preparing Bitumen
Stir the melted sample until it reaches consistency and is free of air bubbles or water after heating the specimen to 90 °C. Put the sample into a container and allow it to cool to room temperature. Put the aforementioned assembly in a water bath that is kept at a constant 25 °C temperature.
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Bitumen Penetration Testing
Water from the water bath should be poured into the transfer dish. Put the sample in the transfer dish, then set the entire assembly beneath the penetration apparatus's stand. Release the needle with a 100 Gram load on the sample's surface for 5 Seconds only. At least three determinations are obtained for each sample. For every determination, a clean needle must be used. The distance between the needle tip and the container side during measurement must be 10mm. Additionally, in every repetition needle placement must be 10 Millimeters apart.
It is crucial that the penetration test procedure is carried out precisely because even a minor error can have a significant impact on the outcomes. The following are the most typical mistakes:
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Inadequate sample collection and preparation.
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Inadequate care for needles and laboratory apparatus.
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Wrong time and temperature.
The greatest difference between the highest and lowest readings in repeated measurements for each sample shall be:
