Consistency of a bituminous material expressed as the distance in tenths of a millimeter that a standard needle vertically penetrates a sample of the material under known conditions of loading, time, and temperature.
In addition, Penetration value test on bitumen is conducted to determine the rigidity or uniformity of bituminous material. A 80/100 grade bitumen signifies that its penetration value remains among 80 & 100.
Also Penetration refers to vertical distance traversed or infiltrated by the point of a standard needle into the bituminous material under particular conditions of load, time and temperature. Also This distance is calculated in one tenths of a millimeter.
In addition, main purpose of penetration test is to assess the conformity of bitumen. Furthermore, It isn`t recommended to use in connection with testing of road tar because of high surface tension exposed by these materials.
1. Reliability of bituminous material
2. Bitumen usability for utilized under various atmospheric conditions and construction types.
Equipments for Penetration Test for defining the penetration value of bitumen
Container: It is a flat bottomed cylindrical metallic dish having necessary diameter 55 mm and depth 35 mm. If the penetration is of the order of 225 or more, dish of 70mm diameter and 45mm depth is essential.
Needle: It belongs to a straight, extremely polished, cylindrical and hard steel rod.
Water bath: It remains at 25° ± 0.1 °C that comprises minimum 10 litres of water, sample is submerged to a depth not below 100mm from top.
Transfer dish or tray: It provides support to the container & should not rock it.
It should contain the ability to submerge container entirely throughout test.
Penetration apparatus: It facilitates needle to infiltrate devoid of much friction & is perfectly calibrated to produce results in one tenth of a millimeter.
Thermometer: Range 0- 44 °C and in readable upto 0.20 C.
Time measuring device: It brings exactness of l second.
Safeguards recommended throughout Penetration Test
No movement of the container we allow when needle enters into sample.
There should be no extraneous matter in the sample.
The needle should be cleansed with benzene and dehydrated prior to penetration.
Nominal capacity of bitumen in Iran is approximately 4.5 million tons and actual production is 3.5 million tons which local consumption is 2.8 million tons and the rest exporting.
Total productions of bitumen during 8 years remain the same and each year 3.5 million tons bitumen produced. Also Problem of bitumen production daily usage of bitumen is main reason that there is not any research and development in this sector and whatever bitumen refineries producing there is demand for that in market. Also The second issue is selling in bulk and using second hand drum.
The main problem in export of bitumen is packing and purchase from refineries which has too much relation and lobby. However Normally European countries importing bitumen in bulk since oily drum has too much extra cost for them to transfer to special zone of oil garbage. Also Paying subside to bitumen exporter from 1998 to 2009 Export of bitumen from Iran had some support from government, but now all exported who exporting bitumen and other oil products has to pay tax. Also International bitumen exhibitions and syndicate.
It`s including all road bitumen grades for paving application as asphalt cement and penetration starting from 10/20 up to 160/220 but specialist on bitumen 40/50, bitumen 60/70, 80/100 and 85/100 which is most consumable bitumen in worldwide market. In the other hand, our bitumen is famous quality of bitumen since raw material “vacuum bottom” is very light compare to other countries.
Available packing is new steel drum, Bulk bitumen, Bitutank.
Bitumen we produce from crude oils through fractional distillation process. Crude oil also heated to 300 _ 350 C. Also It fed into a distillation column. This process done by allowing lightest fractions of crude to separate, through vaporization, from heavier fractions, which remain liquid.
Higher boiling point fractions are then drawn – off via a heat exchanger and enter a vacuum distillation column. Also This process produces a short residue. However It used to manufacture several grades of bitumen. Pressure and temperature conditions within the vacuum process will determine hardness of short residue, and as such the grade of bitumen produced. Also It could further modified by air blowing through 250 – 300 C.