Bitumen Production Process

Refined Bitumen is produced from selected crude oils through a process of Fractional Distillation. The crude oil is heated to temperatures of between 300 and 350 degrees Celsius and fed into a distillation column allowing the lightest fractions of the crude to separate, through vaporization, from the heavier fractions, which remain liquid. The production is a specialist activity and is not carried out in all oil refineries. Bitumen requires crude oils with specific characteristics and only some crude oils are suitable. There are 94 oil refineries in Europe (EU15) of which 63 produce bitumen.

Bitumen is an engineering material and is produced to meet a variety of end-use specifications based upon physical properties. Bitumen may be customised for special road applications and hundreds of grades have also been developed for the non-road industrial segment, including roofing and sound-proofing.

source: trencome.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Fluxed Bitumen

Fluxed bitumens are bitumen preparation where the viscosity of the binder has been reduced by the addition of relatively non-volatile oils.

The added oil is called a fluxing agent and the resulting product fluxed bitumen. Fluxed bitumen is used where traffic and climatic conditions make slow curing of the binder desirable. The fluxing agent prolongs the period before serious hardening of the binder affects its performance. It is desirable that the binder remains as soft as possible, consistent with its ability to hold aggregate under the required conditions of traffic.

source:goda02.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Road Recycling Methods

Purpose

Roads are rehabilitated to correct deficiencies such as rutting, cracking, oxidation, brittleness, irregular shrinkage, and aggregate stripped of asphalt.

Methods

The following methods of roadway rehabilitation recycle old pavement into new:

Cold, In-Place Recycling. The pavement is removed by cold planing to a depth of 3 to 4 inches. The material is pulverized, sized, and mixed with an additive. Virgin aggregate may be added to modify RAP characteristics. An asphalt emulsion or a recycling agent is added, then the material is placed and compacted. An additional layer is optional, such as a chip seal, or 1 to 3 inches of hot-mix asphalt.

A 3-piece "train" may be used, consisting of a cold planing machine, a screening/crushing/ mixing unit, and conventional laydown and rolling equipment. This "train" occupies only one lane, thus maximizing traffic flow. Caltrans has used cold in-place recycling in over 25 projects in California.

According to the Asphalt Recycling and Reclaiming Association, cost savings can range from 20 to 40 percent over conventional techniques. Because no heat is used, energy savings can be from 40 to 50 percent.

Hot Recycling. At a central plant, RAP is combined with hot new aggregate, and asphalt or a recycling agent to produce AC, using a batch or drum plant. The RAP is usually obtained from a cold planing machine, but could also be from a ripping/crushing operation.

Hot, In-Place Recycling. The pavement is softened by heating, and is scarified or hot milled to a depth of 3/4 to 1-1/2 inches and mixed. New hot mix material and/or a recycling agent is added in a single pass of the machine. A new wearing course may also be added with an additional pass after compaction.

Hot Mix--Remixing. The road is heated to 1-1/2 to 2 inches, and the existing AC is removed to that depth. It is then mixed with virgin mix and/or rejuvenating agents and laid as a single course.

Hot Mix--Repave. This method is the same as remixing, but it is overlaid with new hot mix.

Hot Mix--Heater Scarification. This method is appropriate for roadways that have a stable and structurally adequate base. The road is heated, scarifiers scrape and loosen the pavement, rejuvenating agent is applied, and the surface is leveled in preparation for the addition of a final, thin, wearing course.

Full-Depth Reclamation. All of the asphalt pavement section and a portion of the underlying materials are processed to produce a stabilized base course. The materials are crushed and additives are introduced; the materials are then shaped and compacted, and a surface or wearing course is applied.

source:calrecycle.ca.gov

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Polymer-Modified Bitumen

Polymer-modified bitumen or modified bitumen (MB) sheet membranes were developed in Europe in the early 1960s and have been in use in the U.S. since the mid 1970s. Polymer-modified roof membranes are composed of reinforcing fabrics that serve as carriers for the hot polymer-modified bitumen as it is manufactured into a roll material. MB roof system membranes are composed of multiple layers, much like BUR membranes. MB roof systems typically are installed as a two-ply system and almost always are fully adhered.

There are two types of MB roofing membranes:

SBS polymer-modified bitumen membranes commonly are installed in hot moppings of asphalt (similar to BUR systems) or cold adhesive. Some SBS modified membranes are self adhering; that is, they contain an adhesive backing.

APP polymer-modified bitumen membranes typically are heat-welded or torch-applied. Consumers should be cautioned that Rain-tite does not recommend torch-applying a modified bitumen membrane sheet directly to a wood deck.

Generally, APP modifiers impart a “plasticized” quality to asphalt, and SBS modifiers impart a “rubberized” quality to asphalt. MB membranes and EPDM, a thermoset membrane, often are confused by consumers because of colloquialisms used by roofing contractors. MB and EPDM membranes are sometimes called “rubber roofs.”

Surfacings for MB membranes include aggregate surfacing, mineral surfacing, metal foil-laminate surfacing and smooth liquid-applied surfacing.

A roof system composed of a built up roof membrane with 2 plies or 3 plies and a polymer-modified bitumen membrane cap sheet is commonly referred to as “hybrid” system. This type is widely considered to be a polymer modified bitumen membrane system.

source: rain-tite.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Tips on Commercial Roofing Evaluations

Commercial roofing is one of the most demanding areas for expertise in the insurance industry today, as there are millions of commercial structures and hundreds of different roofing systems and variations in application. The history of a building’s roof may have a significant influence on its performance. There may be multiple layers of roofing on a single building, and the materials and their applications have changed over the years.

Roofing Systems
The three most common roofing systems are built-up roofing, modified bitumen roofing and single-ply roofing.

Built-up roofing comprises multiple layers of felt sandwiched together with molten asphalt, and typically covered with a protective coating or a roll-roofing cap-sheet. Built-up systems offer redundancy because of layers of reinforcements.
Modified bitumen roofing systems normally comprise a felt base sheet covered with a modified bitumen cap sheet. The modified bitumen cap sheet comprises reinforcement coated with asphalt mixed with a plastic or rubber to make the bitumen more tough and tear-resistant. The modified bitumen is covered with a protective coating such as aluminum-rich paint or granules to protect it from sun exposure.

Single-ply roof systems comprise a variety of plastics and rubbers: ethylene propylene diene monomer (EPDM), thermoplastic olefin/polyolefin (TPO) and polyvinyl chloride (PVC). These systems are single-layer applications of roofing sheets bonded along their seams with heat or adhesive. The seam bonds keep water from infiltrating the roofing. Single-ply systems are designed for direct exposure to sunlight.
When evaluating a roof system it is important to determine the constituents and attachment of the system.

Hail Damage
Hail storms typically have a predominant fall direction. The direction can be determined by examining building features on and off the roof. Hail can leave spatter marks on oxidized surfaces, such as electric junction boxes, and often leave evidence of impact as dents in metals such as air-conditioner cooling fins, roof vents and flashing. Roofing surfaces exposed to the predominant direction of hail-fall will exhibit damage first, and this damage should be the most severe.

Roofing systems installed over softer substrates are more susceptible to hail than those installed over stiffer substrates, which provide additional resistance to hail. Further, areas of ponded water can accelerate the deterioration of roofing membranes and make these areas more susceptible to impact.
Evaluation of large hail strikes against built-up and modified bitumen roof systems often requires the removal of roofing cores, which are transported to a lab. There, the sample is examined under magnification and the bitumen is removed from the core with solvent to examine the reinforcing for strain and tears characteristic of impacts. Hail damage to single-ply roofing systems typically is discernible in the field, but it may be helpful to remove cores from the roofing and examine certain areas with a microscope and/or high intensity backlighting to identify fractures caused by hailstone impacts.

Wind Damage
A building has widely varying force levels on its roof surfaces, and it is reasonable to expect the most severe wind damage to occur at the windward corners and edges of the roof where wind forces are the strongest. Building codes require more uplift resistance capacity for roofing in these areas. It is not uncommon for roof fastener patterns on shoreline structures and tall buildings to require 50 percent more fasteners along the edges and 100 percent more fasteners in roofing corners than in the field of the roof.
If wind forces have reached levels strong enough to damage the common commercial roofing systems, there typically is some combination of lifted, torn, and/or peeled back roofing concentrated where wind forces are the strongest at the windward edges and corners of the roof.
Additionally, examine roofing at roof penetrations looking for wrinkles and tears or any other evidence of roof membrane displacement. If roofing failure has occurred at wind speeds less than expected, examine and document the roof system attachment within those areas. Often premature failure occurs due to inadequate fasteners, inadequate adhesion, or some combination of the two. Situations such as these may be significant subrogation opportunities.

By Kenneth R. Gilvary
source:claimsjournal.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Bitumen Grading

Bitumen is a thermoplastic material, that is, its stiffness is dependent on its temperature. Its stiffness decreases as its temperature is increased. This temperature versus stiffness relationship is different for different bitumen based on the origin of the petroleum crude and/or method of refining.

Chewing in mouth was the first mode of testing to determine stiffness (hardness) of bitumen during the late 19th century. Experienced bitumen inspectors used the technique for testing and accepting bitumen for paving. Obviously, the test temperature was 98.6 F (37 C) equal to the average human body temperature.

Grading of bitumen by penetration test at 25 C was adopted in 1903, about 100 years ago. In penetration test a needle loaded with 100 grams is allowed to penetrate the bitumen maintained at temperature of 25 C in a water bath, for 5 seconds. The resulting penetration is measured in mm;1 penetration unit = 0.1 mm. The greater the penetration, the softer is the bitumen.

Viscosity grading at 60 C was introduced in the Unites States during 1970s. Viscosity Test is a more scientific measure of consistency than Penetration. Various tests are used to measure the resistance to flow of bitumen and to thereby define its consistency Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress.
In everyday terms (and for fluids only), viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity. Put simply, the less viscous the fluid is, the greater its ease of movement (fluidity).

Viscosity Grade Bitumen is widely used in spraying applications such as surface-dressing and paving in very cold climate. It is also used to manufacture Bitumen emulsion and Modified Bitumen products.



Sources: benzeneinternational.com, engineerstoday.blogspot.com, Singh, P. (2007). An overview of the viscosity grading system adopted in india for paving bitumen. Kandhal Indian Highways

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Modified bitumen

Modified bitumen is formulated with additives to improve their service performance by changing such properties as their durability, resistance to ageing, elasticity and/or plasticity. These modifiers may be polymers, crumb rubber, sulphur and polyphosphoric acid.

The most common types of modifiers being used are APP (Atactic Polypropylene) and SBS (Styrene Butadiene Styrene). These two types were discovered in Europe. Normally to create roofing grade asphalt; asphalt flux is air-blown at elevated temperatures which convert the flux to roofing grade asphalt. In the early 1970’s, the Italians, lacking the blowing equipment, were looking for a product that would convert asphalt flux into a usable roofing product. They discovered that if Atactic Polypropylene (APP) - a by-product of propylene polymerization - was added to asphalt then it gave the asphalt some plastic properties. While APP was being looked into in southern Europe, northern Europe was experimenting with a different type of modifier called Styrene Butadiene Styrene (SBS). The French and Germans found that if they added 10%-15% of SBS rubber to asphalt, the asphalt’s characteristics changed to those of the rubber additive.

Modified bitumen is widely used in the production of roofing felt and in paving applications.

Sources: roofhelp.com,  bp.com,  eurobitume.eu

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.