Asphalt 8 Additional File Download
Katharyn Kasson
Damn, those asphalt tiles are just what I needed! It's one of those mods that you don't know you need until you see it. Would you consider making walls and roof stuff for the construction of small hangars?
Data shows that asphalt art projects at problematic intersections or locations in need of safety improvements can lead to a dramatic reduction in traffic crashes and unsafe driving. The Asphalt Art Safety Study, released by Bloomberg Philanthropies in collaboration with Sam Schwartz Consulting in 2022, found traffic safety to be demonstrably improved across a cohort of 22 asphalt art projects in the U.S. The study results showed a 50% drop in the rate of crashes involving pedestrians or cyclists and a 27% increase in the rate of drivers yielding to pedestrians with the right of way. Other local impacts include:
Resources for cities:
To help create asphalt art projects, cities can consult with the Bloomberg Associates Asphalt Art Guide and other resources on AsphaltArt.bloomberg.org. Materials in English, Spanish, French and other languages have been downloaded in 90 countries. More information is also available on Bloomberg Connects, the free mobile app for arts and culture.
European countries are using technologies that appear to allow a reduction in the temperatures at which asphalt mixes are produced and placed. These technologies have been labeled Warm Mix Asphalt (WMA). The immediate benefit to producing WMA is the reduction in energy consumption required by burning fuels to heat traditional hot mix asphalt (HMA) to temperatures in excess of 300 F at the production plant. These high production temperatures are needed to allow the asphalt binder to become viscous enough to completely coat the aggregate in the HMA, have good workability during laying and compaction, and durability during traffic exposure. With the decreased production temperature comes the additional benefit of reduced emissions from burning fuels, fumes, and odors generated at the plant and the paving site.
All five technologies appear to allow the production of WMA by reducing the viscosity of the asphalt binder at a given temperature. This reduced viscosity allows the aggregate to be fully coated at a lower temperature than what is traditionally required in HMA production. However, some of these technologies require significant equipment modifications.
Aspha-Min is a product of Eurovia Services GmbH, Bottrop, Germany. It is available in a fine white powdered form in 25 or 50 kg bags or in bulk for silos. It is a manufactured synthetic zeolite (Sodium Aluminum Silicate), which has been hydro thermally crystallized. The percentage of water held internally by the zeolite is 21 percent by mass and is released in the temperature range of 185 - 360 F. By adding Aspha-Min to the mix at the same time as the binder, a very fine water spray is created. This release of water creates a volume expansion of the binder that results in asphalt foam and allows increased workability and aggregate coating at lower temperatures.
Eurovia recommends adding Aspha-Min at a rate of 0.3 percent by mass of the mix, which can result in a potential 54 F reduction in typical HMA production temperatures. This reduction in temperature is reported to lead to a 30 percent reduction in fuel energy consumption. Eurovia states that all commonly known asphalt and polymer-modified binders can be used as well as the addition of recycled asphalt.
WAM-Foam is a product of a joint venture between Shell International Petroleum Company Ltd., London, UK and Kolo-Veidekke, Oslo, Norway. In WAM-Foam the binder is formed using two separate binder components in the mixing stage. By dividing the binder into two separate components, a soft binder and a hard binder in foam form, lower asphalt mixture production temperatures can be achieved. The soft binder component is mixed with the aggregate in the first stage at approximately 230 F to achieve full aggregate coverage. The hard binder component is mixed in a second stage into the pre-coated aggregates in the form of foam. Rapid evaporation of water by injecting cold water into the heated hard binder as it is added to the mix produces a large volume of foam. The hard binder foam combines with the soft binder to achieve the required final composition and properties of the asphalt product.
Shell states that WAM-Foam's success depends on careful selection of the soft and hard components. In some cases it is recommended to use an adhesion improver in the first mixing stage. Shell also states that initial coating of the aggregate in the first mixing stage is vital to prevent water from reaching the binder and aggregate interface and entering the aggregate and that water must be removed from the asphalt mix to ensure a high quality end product. Shell reports that the decreased production temperatures of the WAM-Foam process can lead to plant fuel savings of 30 percent, which results in a 30 percent reduction in CO2 emissions.
Sasobit is a product of Sasol Wax (formerly Schümann Sasol), South Africa. Sasobit is described as a modifier or "asphalt flow improver". It is available in 2, 5, 20 and 600 kg bags. On request it can be supplied in flakes or powdered form. Sasobit is a fine crystalline, long chain aliphatic hydrocarbon produced from coal gasification using the Fischer-Tropsch (FT) process and is otherwise know as an FT paraffin wax.
The makers of Sasobit emphasize the difference between naturally occurring bituminous waxes and FT waxes in terms of their structure and physical properties. The difference reportedly arises from their much longer chain lengths and the fine crystalline structure of the FT waxes. The predominant chain length of the hydrocarbons in Sasobit is in a range of 40 to 115 carbon atoms. The chain lengths of bituminous paraffin waxes naturally found in asphalt range from 22 to 45 carbon atoms, resulting in a lower melting point than FT waxes.
Sasol Wax states that the melting point of Sasobit is approximately 210 F and is completely soluble in asphalt binder at temperatures in excess of 240 F. It produces a reduction in the binder viscosity. This enables production temperatures to be reduced by 18 - 54 F. At temperatures below its melting point, Sasobit forms a lattice structure in the asphalt binder that is the basis for the reported stability of asphalts that contain Sasobit. At service temperatures, Sasobit modified asphalts are reported to display an increased resistance to rutting. In addition Sasol Wax reports improved "compactibility" with an increase in the degree of compaction for the same roller loading as unmodified asphalt.
Sasol Wax recommends adding Sasobit at 3 percent by weight of the mix to gain the desired reduction in viscosity and should not exceed 4 percent due to the possible impact on the binder's low temperature properties. Sasobit can be blended into hot binder at the blending plant using a simple stirrer. A high shear mixer is not required. It is anticipated that in-line blending of melted Sasobit with the asphalt binder stream at the plant will be finalized in the near future. Direct blending of solid Sasobit at the plant is not recommended because it will not give a homogeneous distribution of Sasobit in the asphalt.
Evotherm is a product developed by MeadWestvaco Asphalt Innovations, Charleston, South Carolina. Evotherm uses a chemical additive technology and a "Dispersed Asphalt Technology" delivery system. MeadWestvaco states that by using this technology a unique chemistry customized for aggregate compatibility is delivered into a dispersed asphalt phase (emulsion). During production, the asphalt emulsion with Evotherm chemical package is used in place of the traditional asphalt binder. The emulsion is then mixed with the aggregate in the HMA plant. MeadWestvaco reports that this chemistry provides aggregate coating, workability, adhesion, and improved compaction with no change in materials or job mix formula required.
PQ Corporation recommends the addition of 0.25% by weight of the mix, or 5 pounds of Advera WMA per ton of asphalt mix. PQ Corporation states that their technology works with dense, gap and open graded mixes and workability improvements can occur with polymer modified mixes and mixes containing higher recycled asphalt pavement (RAP) contents. Since Advera WMA is an inorganic material it does not change the performance grade of the asphalt binder. Advera WMA is manufactures in plants located in Jeffersonville, Indiana, USA and Augusta, Georgia, USA. It is available in bags, bulk bags (supersacks), and bulk delivery by truck and rail.
Asphaltan B is a product of Romonta GmbH, Amsdorf, Germany. It is available in granular form in 25 kg bags. Created specifically for "rolled asphalt", Asphaltan B is a mixture of substances based on Montan wax constituents and higher molecular weight hydrocarbons.
Romonta recommends adding Asphaltan B at 2 to 4 percent by weight. It can be added to the asphalt mixing plant or directly at the binder producer and can also be added to polymer-modified binders. The melting point of Asphaltan B is approximately 210 F. Similar to FT waxes, it acts as an "asphalt flow improver" with associated reduced production temperatures. Romonta does not specify how much the production temperature can be lowered. Like FT waxes, Romonta also reports increased "compactibility" and resistance to rutting.
Anova warm mix additive is a product of Cargill, headquartered in Minneapolis, Minnesota. Anova warm mix additive is a bio-based, non-hazardous, non-corrosive liquid that is added to asphalt mixtures to significantly improve the quality and reliability of asphalt pavement compaction at an efficient dosage.
Cargill has demonstrated globally that Anova warm mix additive can achieve target compaction with a 100F reduction in temperature. By using a warm mix additive, producers who decrease their plant temperatures can also realize savings in GHG emissions. Cargill Anova warm mix additive allows you to use production temperatures up to 80F lower than conventional hot mix asphalt (HMA). Mixing asphalt at lower temperatures results in less risk, fumes, bitumen aging, energy and costs.
ffe2fad269