Gilsonite is a pure hydrocarbon with a melting point of between 160 ºC (320 ºF) and 220 °C (428 ºF), found in Gilsonite mines that are hardened petroleum. Due to its common oil base, it is easily comparable to crudeoilbitumen (refined bitumen). In combination, the molecules of Gilsonite and bitumen are very close to each other and when combined, they form a compound that has the hardness and durability of Gilsonite on the one hand and maintains the flexibility of bitumen.
Gilsonite is found in underground Gilsonite mines as a hard, black material with a glossy surface. Due to the fragility of this material, it is often used as a Gilsonite powder that is dark brown to black. The main material consists of bitumen which is why Gilsonite is also called natural bitumen and miners seek Gilsonite mining. Since its discovery in the 1860s, it has been used mainly in polishing coatings, electrical insulation, and moisture insulation. Today, this material is used in more than 160 products. The first use of this material today is in black paint, printer ink and powder, mud and cement drilling for oil wells, asphaltoptimization, sand casting additives, and a range of chemical products.
The high percent of Nitrogenous (N) compounds in Gilsonite gives it high adhesion and at the same time increases its oxidation resistance. The lack of sulfur compounds in the material also reduces the quality of the resulting products. Studies show that adding 5% to 15% Gilsonite to bitumen significantly increases the hardness and deformation resistance without significantly affecting viscosity and elasticity.
Gilsonite is available in various degrees and is classified according to its degree of softness. The degree of softness is used as an approximate guide to dissolving the adhesive and solvent behaviors. The chemical difference between the degrees of Gilsonite is negligible, with only minor differences in molecular weight and resin content. Gilsonite is natural asphalt, that is used as a Bitumen binder modifier . We investigate the effect of combining Bitumen and Gilsonite in the same base binder. Adding 13% – 14% Gilsonite increases performance of asphalt. Also, the viscosity of modified binders by Gilsonite is always high. Gilsonite can be used as an alternative modifier to reduce the cost of asphalt mixture production and compaction in the field.
Gilsonite in Construction:
Gilsonite in construction normally is mixed in 180 ºC (356 ºF) – 220 ºC (428 ºF) with a very simple blender. High–performance road surfaces is use Gilsonite. Gilsonite’s properties make it the go–to modifier for hot mix pavements and pavement sealers. Gilsonite makes roads less susceptible to high–temperature and deformation performance issues. When you use Gilsonite in road construction, the asphalt binder will produce a stronger road that can be thinner by nearly 20% compared with other pavements. As an aggregate modifier, Gilsonite can be added directly at the hot mix plant with no additional equipment. The excellent bonding properties of Gilsonite will produce a high–strength, high–performance pavement that also resists water stripping. Many construction processes are controlled by comparing the desired product, conceived during design, to the product produced during construction. The asphalt pavement construction process is often controlled in this manner. Control is often based on testing of components and the assemblies of materials, the construction process and the finished asphalt pavement. The success of the asphalt pavement construction project is usually judged based on how well test results produced during construction compare with criteria considered representing the desired product conceived during design.
Gilsonite has been the subject of exhaustive study to improve characteristics for use in paving. Various properties of asphalt are manipulated to produce a product that has the (1) Appropriate wear properties, (2) Rut resistance, (3) Fatigue and (4) Low temperature cracking resistance, (5) Adhesion strength, (6) Viscosity and (7) Pour point. Rut resistance is resistance to longitudinal surface depressions in the wheel paths. Adhesion strength is the maximum adhesion strength of the joint sealant and the joint reservoir including but not limited to the aggregate and the binder.
Crack sealer produced with the blend of bitumen with Poly Styrene–Butadiene–Styrene (SBS), Gilsonite, rubber process oil, crumb rubber in special temperature and pressure is used for sealing cracks and joints in the asphalt pavement, parking lots also cement pavement. It is used to seal expansion, longitudinal, transverse crack and construction joints between concrete and asphaltic shoulders. Gilsonite is an environmentally friendly product used to repair and seal asphalt. Gilsonite joint sealer and crack sealer is widely used in the world. The preferred embodiment of the invention employs a roofing adhesive or cement for filling the parking lot crack, either with asphalt or concrete after it has been thoroughly cleaned either with air or water. The adhesive is preferably modified bitumen rubber asphalt normally used for bonding roofing materials.
Shove resistance is resistance to permanent, longitudinal displacement of a localized area of the pavement surface caused by traffic pushing against the pavement. Heavy hydrocarbon that can be derived from, without limitation, natural asphalt (Gilsonite), shale asphalt, bottoms from a solvent de–asphalting process, hard asphalt, blown asphalt, stiff refined asphalt and a flux. Asphalt is usually the base ingredient for the primer and the binder.
A primer can be asphalt, fibers (including but not limited to, mineral or cellulose), processing agent (including but not limited to, Oligomeric wax, Carboxilated, derivative of Oligiomeric wax, or low molecular weight polyolefin) and polymeric or elastomeric additive. A primer melts to the aggregate. Asphalt binders without polymers are referred to as “neat”.
Details of Gilsonite Mixture in Asphalt:
It has been discovered that asphalt cement can be toughened with Gilsonite and thinned with reactive oil. Reactive oil is oil that contains a high content of unsaturated fatty acids. By using a reactive oil, the oil would cure or react after application of the asphalt cement to the highway, thereby allowing for a lower viscosity application by curing later to prevent “Rutting”.
Rutting is discribed as surface depression in the wheelpath. Pavement uplift (shearing) may occur along the sides of the rut. Ruts are particularly evident after rain when they are filled with water. There are three basic types of rutting:
(1) Mix Rutting: Occurs when the subgrade does not rut yet the pavement surface exhibits wheelpath depressions as a result of compaction/mix design problems.
(2) Subgrade Rutting: Occurs when the subgrade exhibits wheelpath depressions due to loading. In this case, the pavement settles into the subgrade ruts causing surface depressions in the wheelpath.
(3) Densification: Occurs when there is insufficient compaction during construction and the pavement continues to compact under traffic loading.
The preferred natural asphalt is asphaltite such as Gilsonite. Preferably one having a melting or softening point near about 149 ºC (300 °F) is optimal. At this temperature, it is more easily softened and blended with the petroleum asphalt.
How to Mix Gilsonite in Asphalt:
Gilsonite should be added slowly at the vortex. Provisions should be made to re–circulate the hot Bitumen through re–circulation piping. The most important item is that the minimum temperature should be about 170 ºC (338 ºF) to 175 °C (347 ºF). Anything significantly less than this will extend mixing time. For typical (5% – 10%) substitution concentrations, 2 – 4 hours of mixing after addition is completed should be sufficient. For master batch concentrations (Over 10% Gilsonite) re–circulation overnight is preferred.
Packing of Gilsonite “Natural Asphalt” Lump and Powder Form “Micronized”:
• Gilsonite in Lump form like rock packed in 500 – 1,000/Kg. Jumbo Bag
• Gilsonite 200 Mesh packed in 500 – 1,000/Kg. Jumbo Bag
• Gilsonite 300 Mesh packed in 500 – 1,000/Kg. Jumbo Bag
• Gislonite 30 – 40 Mesh packed in 500 – 1,000/Kg. Jumbo Bag
• Gilsonite 100 Mesh packed in 500 – 1,000/Kg. Jumbo Bag
• Gilsonite 300 Mesh packed in 25/Kg. PP Bag
• Gilsonite 200 Mesh packed 25/Kg. Multi Paper Bag
• Gilsonite 200 Mesh packed 50/lbs Multi Paper Bag