International asphalt plant manufacturers have been reporting major successes with their products, which are now working on highway and airport projects worldwide.
At the same time trials are being carried out on various types of asphalt, including one in Brazil where
Indeed, Brazil is proving a big success for Swiss-based international company
“Transport during delivery is as simple as it is for the plant operators. The Prime 140 simply sets its wheels rolling and is gone,” says the company.
During 2013, ten plants were shipped to locations in Central and South America, but following its appearance at the
Ammann says that two-thirds of the plants produced so far by Ammann do Brasil have gone to Brazilian companies, although it points out this does not mean they will stay in the country. Many of the large construction companies based in Brazil operate across Latin America and also in Africa.
Improvement and maintenance work on the RS-122 between Caxias do Sul and Antônio Prado in the south of Brazil started in March 2014.
The consortium of four construction companies operates two Prime 140 plants on the 46km and 48km long motorway sections.
Ivan Ideraldo Bonet, engineer and technical manager at CSA Construções, explains that the decision to buy Ammann plants was made to ensure the high demands on the roadbuilding work would be met in full.
“This model also allows mix loading and mixing time parameters for smaller quantities, a feature we find very accommodating for smaller assignments in rural regions,” he says.
The company Dalfovo Construtora was one of the first in the country to purchase an AFW 350 paver from Ammann, and its own Prime 140 now supplies the asphalt for the project.
“We hope the asphalt mixing plant will work as well as the other machine so we will be able to complete our work even sooner without jeopardising quality,” says company owner Juarez Alex Dalfovo.
He intends to use the high-performance plant not only for the production of asphalt mixes for road construction but also for surfacing industrial plots and premises in and around Caxias do Sul.
Ammann says that customer opinions demonstrate that the technology inside the mobile mixing plant, designed specifically for the conditions in this part of the world, meets their high expectations and demands.
Another important transport project being carried out by construction company Contek Engenharia in north-east Brazil is also using a Prime 140 to produce asphalt.
“Project PE-280 requires a road surface made of a hot asphalt and concrete mix,” says Hercílio de Souza Lira Filho, Contek’s civil engineering expert.
“Our goal is to produce 42,000tonnes of asphalt for this region in 12 months. But we reckon that we will finish within nine months.”
A Prime 140, working for construction company Construtora Simoso since December 2013 in São Paulo in the south-east, the most densely populated and economically significant of Brazil’s 27 federal states, is producing asphalt for road improvement and maintenance work.
“Ammann asphalt mixing plants are equipped with a fully automatic, electronic burner that helps save heating oil,” says Fabio Simoso, the company’s construction engineer.
“The plant has an output of up to 140tonnes/hour and is easy to transport.”
Another advantage, according to Simoso, is the plant control system during the production of asphalt.
“Asphalting roads requires a long preparation process. The asphalt mixing plant is not needed until the final phase, but the longer the ingredients are mixed, the better the end result.”
Meanwhile,
The Astec Voyager 120 is built around a counter flow drum featuring Astec V-Flights, which provide greater uniformity of the aggregate veil during the drying process. This is said to result in better heat transfer, a reduction of fuel use, and increased productivity.
“To enhance portability, a hydraulically-driven swing-out drag and batcher can be set and ready to go in about ten minutes,” says the company.
“Other features include a reverse pulse baghouse; a controls cab with fully automated PLC controls; gravity take-up with direct drive; air ride suspension, and up to five cold feed bins and two RAP bins. According to Andy Guth, manager of sales and marketing for Astec, the Voyager 120 is designed to round out the highly portable side of the plant line-up.
"We're offering a small, portable plant with 30% recycle capability. The Voyager 120 will be instrumental in markets like Latin America, where contractors do a small job, transport, and do another small job, always on the move,” says Guth.
“These jobs handle 1,814 to 4,535tonnes of material. The availability of recycle will depend on the market.”
Guth further notes: “Response from the industry has been extremely positive on a global scale. To date, Voyager 120 plants have been sold onto three continents and requests for quotes on the plant are steadily coming in from the field.”
In the United Arab Emirates (UAE) equipment from Italian company
US-based, family-owned global transportation and heavy civil construction company,
The terminal’s construction is expected to be completed in four years, and Lane is the prime contractor awarded the runway paving contract, consisting of repaving, ground lighting and drainage for the construction of a new 4.3km long, 60m wide runway and over 20 taxiways. This means the use of over 330,000tonnes of asphalt in six months.
The company’s mechanical team evaluated the solutions available on the market and chose a Marini asphalt plant from
Marini says that the Lane technical team has been particularly appreciative of the modular design of the Marini plant, with a view to increasing work in the near future, and has noted the Top Tower is upgradeable with a recycling ring, including the ability to accept up to 35% recycled materials, and add additional hot mix storage silos.
Application of warm mix asphalt by foaming/ageing assessment
The production of asphalt mixtures at temperatures lower that those traditionally used is already a reality at job sites all over the world through the use of WMA or warm mix asphalt.
Now there are different technologies that modify the asphalt cement, either through the reduction in its superficial tension (surfactant chemical additives) or by the reduction of binding agent viscosity at high temperatures (organic additives, zeolite based additives, wet sand and asphalt foam produced in plants).
Regardless of the technology used, it is said that the change in asphalt cement creates an increase in the workability of the mix, thus improving its adhesive capacity and compaction.
With the aim of studying the asphalt foam technique as a means of producing WMA mixtures, a cooperation project between Ciber Equipamentos Rodoviários (a member of the
Construction company Dimensional Engenharia also participated in the first stage of the project by making available a Ciber UACF 17 P advanced plant, and the site for the application of the technology.
The research started at the end of 2011, and the preliminary results are detailed here.
Seven different mixtures were produced starting with a reference mix produced at 170ºC and compacted at 142ºC, according to the premises of adhesiveness between materials and the temperature x viscosity curve.
Five mixtures were produced with foamed asphalt, while keeping constant the aggregates, particle size, asphalt cement, and project content, the difference between them relies on machining and compaction temperatures.
The laboratory spinning compactor Superpave was used to produce test samples, and for all mixtures compaction happened at ageing times of 0, 30, 60, 90, 120, 150 and 180 minutes to evaluate what impact the time between mixing and compaction has on the mix. After compaction, the test samples went through volumetric and mechanical trials, and comparisons between the warm mixes and the reference ones were carried out. The behaviour regarding fatigue and permanent deformation was similar throughout all samples. By analysing the behaviour of the test samples regarding tensile strength through diametric compression and resilience module, it is possible to see that the mixtures produced at lower temperatures (145°C and 132°C) are less susceptible to hardening with time, when compared to mixtures at 170ºC.
This phenomenon can be explained by the lower ageing of the asphalt binder at lower temperatures. Thus, the warm foamed mix increased the compaction interval, not only for allowing compaction of the mixtures at lower temperatures, but also for keeping constant the quality of the mix for a longer period of time, when compared to mixtures produced at 170ºC.
The companies say that in addition to the benefits to the environment, such as a reduction of fuel consumption at plant and reduction of particulates emissions into the atmosphere, and the benefits during production and compaction, WMA mixes tend to age less than traditional mixtures.
