Bitumen Penetration
What is bitumen penetration grade?
Refinery bitumen is produced at various viscosities and is the penetration grade bitumen. Based on its hardness, the bitumen is characterized using the penetration test. As a result, it is known as Penetration Grade Bitumen. For road bitumen, the penetration bitumen grades vary from 15 to 450. The most typical range, however, is 25 to 200. This is obtained by managing the experiment, which is the distillation procedure. The leftover bitumen can be somewhat controlled by fluxing it with oils to get the desired hardness.
The penetration and softening point values for the corresponding Penetration Grade Bitumen are provided by BS EN 1426 and BS EN 1427, as shown in Table 1. This will make it easier to determine the bitumen grade’s equiviscosity and hardness.
The penetration numbers, i.e., 40/60 as a penetration value of 50 10, denote the grades.
For all penetration bitumen grades, the BS EN 13303 also provides the measure of loss on heating with appropriate limitations. This precaution is taken to guarantee the absence of any volatile substances.
Therefore, nothing is done that would cause the bitumen to set and harden during preparation or the lay course.
To make sure that there are fewer or no contaminants in the bitumen material, the BS EN 12592 defines the solubility values.
Type of Penetration Grade Bitumen is a common type of bitumen used for paving. When bitumen binds the aggregates and gives the bituminous mix a distinctive cohesiveness and stability, it becomes crucial for road building and the creation of asphalt pavements with excellent qualities. Hot mix asphalt for bases and wearing courses is mostly made using this grade of bitumen. Petroleum grade bitumen produced from fractional or vacuum distillation of crude oil is the penetration Grade bitumen that RABIT Co. supplies. The vacuum residue (short residue) feedstock serves as the source of the bitumen that RABIT provides.
The penetration and softening point test is used to define Penetration Grade Bitumen. Only the penetration range is used to designate. The thermoplastic feature of the penetration Grade bitumens leads the substance to soften at high temperatures and harden at lower temperatures. When defining bitumen performance factors, including adhesion, rheology, durability, and application temperatures, this particular temperature/viscosity connection is crucial.
Type of Penetration The penetration and softening point test defines bitumen. Only the Penetration Grade Bitumen range is used to designate.
Bitumen 60/70 is the primary Penetration Grade Bitumen, and it is commonly utilized in all markets. The fundamental tenet of penetration grading is that the deeper the needle penetrates, the less viscous the asphalt is. The performance of the asphalt binder is experimentally (but only loosely) connected with this penetration depth. As a result, in cold regions, asphalt binders with high penetration numbers are utilized, whereas, in warm climates, asphalt binders with low penetration numbers are used.
The early 1900s saw the development of the penetration grading system, which was used to describe the consistency of semi-solid asphalts. The following qualities of asphalt concrete are quantified through penetration grading:
100 g needle penetration depth at 25 °C (77 °F).
The temperature at the flashpoint. At 25 °C (77 °F), ductility.
Trichloroethylene solubility
oven test for thin film (accounts for the effects of short-term aging that occurs during mixing with hot aggregate).
enduring penetration
elasticity at 25 °C (77 °F)
An empirical test approach is used to determine penetration. A Penetration Grade Bitumen sample is stabilized in a tiny container at a consistent temperature in a water bath (normally 25 C). A 100g specified needle is allowed to rest on the bitumen’s surface for 5 seconds. The bitumen is measured by how far the needle pierces it, expressed in units of 0.1mm.
Some bitumens are produced using distillation column fractionation. When oil is heated, vapors of various densities are extracted through a process known as fractions. The hardness of these bitumens determines their classification. A certain type of needle is inserted into a sample, and the depth to which it can pierce the material within a given amount of time and temperature is measured to establish the sample’s hardness. The Penetration Grade Bitumen that has undergone this test is known as road grade bitumen or penetration grade bitumen, and the test is known as the standard penetration test.
Bitumen grade bitumen samples can range in consistency from semi-solid at ambient temperature to semi-liquid under the same circumstances since they have various chemical compositions and production processes.
The bitumen’s hardness may be determined by looking at the penetration numbers acquired during the penetration test. The hardest bitumen is “pen” (15), while the softest is “pen” (450). The phrase “penetration grade bitumen” is frequently shortened to “pen bitumen” or “pen bit” in the construction sector.
Other road binders, including cutbacks, emulsions, and polymer-modified binders, are all addressed below and are based on penetration grade bitumen.
Bitumen grades are largely defined in terms of their needle penetration or “pen.” In comparison to hard bitumens, soft bitumens have higher pen numbers. However, several other requirements must be satisfied within specifications, such as the softening point, solubility, and resistance to hardening. Following are descriptions of these test procedures, which serve as the foundation for most bitumen standards.
Test of penetration
The Tests entail exposing a Penetration Grade Bitumen sample to needle bitumen under predetermined duration, temperature, and load conditions. In most situations, the test is conducted at 25 °C for 5 s with a 100 g weight. On rare occasions, low-temperature bitumen is also tested at the standard five °C circumstances with a load of 200 g for the 60s. 00 DMM.
Test for Softening Point In the Softening Point Test, bitumen discs are prepared to see what temperature they can no longer hold a normal metal ball (Fig. 2.8). All unaltered Penetration Grade Bitumen has almost comparable penetration (800 DMM) and viscosity at the softening point (1200 Pas). As a result, the softening point approximates the bitumen’s equip-viscous temperature (EVT). Knowing the penetration and softening points of the bitumen may be used to determine its temperature susceptibility. Using equations created by Pfeiffer and Van Doormal2(), it is possible to calculate a Penetration-Index (PI), which calculates the impact of temperature on the bitumen’s characteristics. The bitumen will be more temperature vulnerable the higher the PI.
Traditionally, the PI has been incorporated into bitumen specifications, especially in continental Europe.
Benefits of Penetration Grade Bitumen
The test is conducted at 25° C (77° F), which is relatively near to the average temperature of a normal pavement.
The viscosity test, which is carried out at 60° C (140° F), may also offer a stronger connection with low-temperature asphalt binder qualities.
By doing the test at temperatures other than 25° C (77° F), it is possible to assess temperature susceptibility (the change in asphalt binder rheology with temperature).
The examination is rapid and affordable. As a result, it is practical for usage in the field.
Penetration grade bitumen drawbacks
A fundamental engineering parameter like viscosity is not measured by the empirical test.
During the test, the shear rate fluctuates and is rather high. This will impact test findings since asphalt binders normally behave as a non-Newtonian fluid at 25° C (77° F).
A single test at 25° C (77° F) cannot determine temperature susceptibility (the change in asphalt binder rheology with temperature).
The test does not yield data that may be used to calculate the temperatures for mixing and compaction.
