About Bitumen
Bitumen is an adaptable construction material with a diverse range of characteristics. It is defined as an amorphous, black or dark-coloured, (solid, semi-solid, or viscous) cementitious substance. It is principally composed of high molecular weight hydrocarbons, and their derivatives, which is soluble in trichloroethylene and is considerably non-volatile and softens gradually when heated. It possesses waterproofing and adhesive properties and is commonly used in the construction industry, notably for roads and highways. It is obtained through the process of distillation of crude oil, and is also found as a natural deposit or as a component of naturally occurring asphalt, in which it is associated with mineral matter.
Bitumen or bituminous binder is made available in various types with completely different properties.
1. Penetration Grade Bitumen
Penetration bitumen is the most widely used bitumen grade for civil and road construction and for the production of asphalt pavements with superior properties. This grade of Bitumen is mainly used in the manufacture of hot mix asphalt for bases and wearing or surface course for roads and streets. After its production in the refinery, the bitumen is classified by penetration test using a penetrometer apparatus. The deeper the needle penetrates vertically into the bitumen surface, the softer it will be and more suitable for colder regions.
Bitumen 80/100: The characteristics of this bitumen grade confirm to that of S-90 grade of IS-73-1992. This is the softest grade of all available in India. This is suitable for low traffic volume roads and is still widely used in the country.
Bitumen 60/70: This type of grade is harder than 80/100 range and can withstand higher traffic loads. The characteristics of this bitumen grade confirm to that of S-65 grade of IS-73-1992. It is used mainly in construction of National Highways & State Highways in India.
Bitumen 30/40: The 30/40 grade is the hardest of all and can withstand very heavy traffic loads. The characteristics of this bitumen grade confirm to that of S-35 grade of IS-73-1992. It is used in specialised applications such as airport runways and also used for heavy traffic volume roads in coastal cities in the country.
2. Viscosity (Paving) Grade Bitumen
Paving (viscosity) grade bitumen is the bitumen obtained from the distillation process in refineries and conforms to IS 73. Recently, the third revision of Indian Standards for Paving Bitumen Specifications IS 73:2006 has been released by the Bureau of Indian Standards where the grading had been changed from penetration grade to viscosity grade. It states that the highest usage of this bitumen is in India. The grading of Bitumen is changed from penetration grade to viscosity grade in this third revision. Three grades of Bitumen confirming to IS 73:1992 are manufactured and used in India. To improve the quality of Bitumen, BIS revised IS-73-1992 Specifications based on viscosity grade (@ 60 deg. Celsius) in July 2006. As per the Specifications, there are four types of grades namely VG-10, VG-20, VG-30 & VG-40.
Viscosity grade bitumen has a thermoplastic feature which makes the material to soften at high temperatures and hardens at lower temperatures. This temperature viscosity relevance is exceptional when setting out the performance parameters such as the adhesion, rheology, durability, and application temperatures of bitumen. In the Viscosity Grade Bitumen specifications, the most important parameter is based on the Bitumen ductility.
| Grade | Viscosity Range at 60°C (Absolute Viscosity) | Generic Applications |
|---|---|---|
| Grade | Viscosity Range at 60°C (Absolute Viscosity) | Generic Applications |
| VG-10 Bitumen | 800-1200 | Recommended for road construction in cold regions |
| VG-20 Bitumen | 1600-2400 | Used in cold and high altitude regions for road construction |
| VG-30 Bitumen | 2400-3600 | Maximises asphalt performance in hot regions |
| VG-40 Bitumen | 3200-4000 | Works in areas with high traffic loads and stressed areas such as toll booths, pavements and truck parking |
3. Modified Bitumen (CRMB/PMB)
Modified bitumens are formulated with additives to improve their features and performance by changing such properties as their durability, resistance to ageing, elasticity and plasticity. Improving the physical properties allows bitumen to resist the stress caused by temperature variations, high traffic loads, hence enhancing road life and reducing maintenance costs. Polymers are the most important modifiers.
Modified Bitumens are categorised into two variants: Rubber Modified Bitumens and Polymer Modified Bitumens. Rubber Modified Bitumens are produced by using Crumb Rubber or Synthetic Rubber Latex as additives. However, Crumb rubber is mostly preferable. Polymer Modified Bitumens are produced using additives such as Polymers. Polymers are categorised into two types, Elastomeric and Plastomeric.
CRMB (E) Specification as per IRC SP 53 – 2002 and BIS I5462 – 2004
| Specification | Grades and Requirement | |||||
|---|---|---|---|---|---|---|
| Specification | Grades and Requirement | |||||
| -- | CRMB 50 | CRMB 55 | CRMB 60 | |||
| Penetration at 25°C | < 70 | < 60 | < 50 | ISI 203 – 1978 | ||
| Softening point, (R & B), C Min. | 50 | 55 | 60 | ISI 205 – 1978 | ||
| Elastic Recovery of half thread in | 50 | 50 | 50 | ISI 5462 – 2004 | ||
| Flash Point,°C Min | 220 | 220 | 220 | ISI 209 – 1978 | ||
| Separation difference in softening point, | 4 | 4 | 4 | ISI 5462 – 2004 | ||
| (R & B)°C , Max | ||||||
| Thin Film Oven Test (TFOT) on Residue | ||||||
| a. Penetration 25°C , Min % of original | 60 | 60 | 60 | ISI 203 – 1978 | ||
| b. Increase in softening point,°C, Max | 7 | 6 | 5 | ISI 205 – 1978 | ||
| c. Elastic Recovery of half thread in | 35 | 35 | 35 | ISI 5462 – 2004 | ||
| Ductilometer at 25°C , % Min. |
PMB Specifications as per BIS I5462 – 2004
| Specification | Grades and Requirement | |||||
|---|---|---|---|---|---|---|
| Specification | Grades and Requirement | |||||
| -- | PMB 40 | PMB 70 | PMB 120 | |||
| Softening Point,°C (min) | < 60 | < 55 | < 50 | |||
| Penetration at 25°C | 30-50 | 50-90 | 90-150 | |||
| Elastic Recovery of half thread, % ( min ) | 70 | 70 | 70 | |||
| Difference in softening point,°C ( max ), Separation | 3 | 3 | 3 |
4. Bitumen Emulsions
Bitumen is a highly viscous material not feasible at ambient temperatures. One of the best ways to make it practically work is to make an Emulsion with water, which is useful in a wide range of temperatures. Since Bitumen Emulsion does not require heating during application and can be used with damp or cold aggregates, there is no hydrocarbon fume emission which makes this product eco- friendly. BitumenEmulsions belong to the oil-in-water emulsion type where Bitumen globules are dispersed in water with the help of emulsifiers and colloid mill. The emulsions are classified as Cationic (positive ions) or Anionic (negative ions) depending on the ionic charge they possess. Also in India, cationic emulsions are most suitable as they are compatible with all types of aggregates used in road construction.
Cationic Bitumen Emulsions are divided into three categories:
- Rapid Setting (RS) – Emulsion Break is rapid and is further subdivided into RS – 1 and RS – 2.
- Medium Setting (MS) – Emulsion Break is slower than Rapid Setting and can be used for coarse materials with more fine aggregates.
- Slow Setting (SS) – Emulsion Break is slowest compared to the other variants and is generally used with fine aggregates. It is subdivided further into SS – 1 & SS – 2.
Note: In the above notation, R, M & S stands for Rapid, Medium & Slow Setting of Emulsion respectively, and the numbers 1 & 2 signifies low & high viscosity of emulsion respectively.
Bitumen Emulsion Technical Requirements for Cationic Type IS : 8887 – 2004
| Sr. No. | Characteristic | Grade of Emulsion | ||||
|---|---|---|---|---|---|---|
| Sr. No. | Characteristic | Grade of Emulsion | ||||
| RS-1 | RS-2 | MS | SS-1 | SS-2 | ||
| 1 | Residue (% mass max.) on 600 micron IS Sieve | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 |
| 2 | Viscosity by Say bolt Furol Viscometer, | |||||
| (a) Second at 25°C | – | – | – | 20-100 | 20-100 | |
| (b) at 50°C | 20-100 | 100-300 | 50-300 | – | – | |
| 3 | * Emulsion Coagulation at low temperatures | NIL | NIL | NIL | NIL | NIL |
| 4 | Storage stability after 24 hrs % Max. | 2 | 1 | 1 | 2 | 2 |
| 5 | Particle charge | Positive | Positive | Positive | Weak Positive | Positive |
| 6 | Coating ability and water resistance | |||||
| (a) Coating, dry aggregate | – | – | Good | – | – | |
| (b) Coating, after spraying | – | – | Fair | – | – | |
| (c) Coating, wet aggregate | – | – | Fair | – | – | |
| (d) Coating, after spraying | – | – | Fair | – | – | |
| 7 | Stability to mixing with cement | – | – | – | 2 | 2 |
| (% coagulation ) Max. | ||||||
| 8 | Miscibility with water ( Coagulation ) | NIL | NIL | NIL | – | NIL |
| 9 | Test On Residue | |||||
| a. Reside by Evaporation % Min. | 60 | 67 | 65 | 50 | 60 | |
| b. Penetration 25°C/100g/ 5 sec | 80-150 | 80-150 | 60-150 | 60-350 | 60-120 | |
| c. Ductility 27°C /cm Min. | 50 | 50 | 50 | 50 | 50 | |
| d. Solubility in trichloroethylene % Min. | 98 | 98 | 98 | 98 | 98 | |
| 10 | Distillation percent, by volume at : | |||||
| a. 190° C | – | – | – | 20-55 | – | |
| b. 225° C | – | – | – | 30-75 | – | |
| c. 260° C | – | – | – | 40-90 | – | |
| d. 315° C | – | – | – | 60-100 | – | |
| 11 | Water content, percent by mass, Max | – | – | – | 20 | – |
Application of Bitumen
Majority of refined bitumen is used in construction: primarily as building materials used in roads and roofing applications. According to the requirements, bitumen is produced to various specifications. This is done by the refining or blending process.
Approx. 85% of all the bitumen produced is used as the binder in asphalt for roads. It is also used in other pavement areas such as airport runways, parkings and footpaths. Typically, the asphalt is made by mixing sand, gravel and crushed rock with bitumen, which acts as the binding agent. Other additives, such as polymers, can be added to the bitumen to alter its properties according to the requirement for which the asphalt is ultimately intended. Almost 10% of global bitumen production is used in roofing applications, where its waterproofing qualities are invaluable. The remaining 5% of bitumen is used for sealing and insulating purposes in a variety of building materials, such as pipe coatings, carpet tile backing and paints.
| Specification | Grades and Requirement | |||||
|---|---|---|---|---|---|---|
| Specification | Grades and Requirement | |||||
| -- | PMB 40 | PMB 70 | PMB 120 | |||
| Softening Point,°C (min) | < 60 | < 55 | < 50 | |||
| Penetration at 25°C | 30-50 | 50-90 | 90-150 | |||
| Elastic Recovery of half thread, % ( min ) | 70 | 70 | 70 | |||
| Difference in softening point,°C ( max ), Separation | 3 | 3 | 3 |
Quality
All Bitumen supplied is of the highest quality and fully compliant with ASTM and AASHTO, equivalent EN and BS International Standards and Test Methods. SGS Quality Testing and Analysis certification of the Bitumen products inspected when requested, will be compliant with Product Specifications and International Standards. Quality assured manufacturing. Equivalent to BS EN 12591 and BS EN 13924.
Mittal Siddhi Infra Pvt. Ltd. is a prominent importer and supplier of Viscosity Grade Bitumen and different types of bitumen and petrochemical products based on international standards. We provide bitumen on an immediate basis and in bulk quantity for our Indian customers since the most usage of bitumen is in India’s roads.