HIGHLY MODIFIED ASPHALTS (HIMA)

31 July 2020
in: Technical articles,Asphalt,HiMA

One of the questions that arises from the use of modified asphalts is to what extent it is possible to increase the level of polymer in the formula or degree of modification, to further increase the advantages that the modified ones present over the conventional ones.

In standard modified asphalts, the increase in the amount of polymer in the solution leads to an increase in the viscosity of the asphalt. The high viscosities make its handling in the industry impractical, since the asphalt must be heated to high temperatures so that it can be pumped and adhered to the stone aggregates when manufacturing asphalt mix. In a context where the price of fossil fuels and environmental responsibility are increasing, this does not seem to be a viable option.

There are SBS polymers with a high vinyl content (1) that have better compatibility with asphalt. This is due to the fact that it is made up of shorter chains compared to those of the SBS polymers present in the standard modified ones, which also translates into a lower viscosity of the solution (1). Short chains also make the reaction rate faster, further increasing compatibility. All this makes it possible to increase the amount of modifying agent in the asphalt binder without the aforementioned problems occurring. Also, the manufacturing methods are essentially the same with some additions that we will see in this section.

Intermolecular structure

Highly modified asphalts have some key differences that set them apart from standard asphalts, such as the aforementioned amount of polymer. Highly Modified Asphalt, HiMA, is made with 7.5% polymer by weight. From this value, a change in the intermolecular structure of the ligand is observed, which is essential to classify it as highly modified. The continuous matrix becomes formed by the SBS chains and the asphalt molecules become the dispersed phase, creating colloidal groups, as shown in Figure 1. This means that the mechanical properties of the binder are largely determined by the polymeric network, being able to show improvements with respect to standard modified asphalts, as shown by various studies (1,2). The continuous matrix change phenomenon is due to the strong interaction of the SBS polymers with the asphalt, which allows them to increase up to ten times their own volume when associated with maltenes.

Figure 1. Scheme of the transformation of the molecular structure of the binders with the increase of a modifying agent. Adapted from Field and Laboratory Study of High-Polymer Mixtures at the NCAT Test Track (2).

Bibliography

Scholten, Erik J., Vonk, Willem y Korenstra, Jan. Towards green pavements with novel class of SBS polymers for enhanced effectiveness in bitumen and pavement performance . Varsovia : 2nd International Conference on Environmentally Friendly Roads, 2009.
Timm, David H., and others. Field and Laboratory Study of High-Polymer Mixtures at the NCAT Test Track. Auburn : National Center for Asphalt Technology, 2012.

INAUGURATION OF ROUTE 101

29 November 2019
in: Asphalt,Bitaflex AM3,HiMA,Top,News,route 101

COLIER opens duplication of 10 km of double track from Colonia Nicolich to Pando

Last October 25 the opening of the section was held with the presence of the Minister of Transport, Victor Rossi and Intendant of Canelones, Yamandú Orsi, among other national and departmental authorities.

The work was done in record time but ensuring the quality in each of its stages. We are proud to have been able to meet the challenge of providing the BITAFLEX AM3 cement up to 8 trucks a day to make this dream became reality, fulfilling the word of Hebert González.

We invite you to learn more about the work and the inauguration.

The work consisted of a road widening with input from more than one meter of granular material and then a 12cm asphalt AC30 asphalt as black base. In the old road patching she performed and then applied across the width rolling in a folder with 5 cm modified asphalt BITAFLEX AM3. Colonia Nicolich several test sections were made with the new highly modified asphalt cement HiMA as reported earlier (https://bitafal.com.uy/nuevo-tramo-con-asfalto-hima/).

Also in record time laces and padding to the median strip separating the two carriageways, and both vertical and horizontal signs they were performed.

The work includes several roundabouts, made of concrete, at the entrance to the Science Park and at intersections with Ponce Street León, Avenida Rambla Costanera and roads El Gallo and Los Horneros and in front of the Military School Aeronautics (EMA).

All these improvements will positively impact both in economic and social development of the area but even more traffic in a route increasingly congested. To complement the latter works are being made to illuminate the entire stretch.

The inauguration began when 19, at the roundabout of E.M.A. on Route 101, where a ceremony was held in the words of the Minister of the mayor of Pando, of the Intendant of Canelones well as the Ing. Juan Echeverz, who thanked everyone who made this work possible. Especially those who are daily on site.

The Minister of Transportation and Public Works, Víctor Rossi, explained that the portfolio intends that the circuit made up of these routes become an exit corridor to the east of the country, capable of contributing to the decongestion of the Interbalnearia route that faces a important circulation of vehicles in summer season. The inaugurated works are part of the works carried out with this objective. The Minister also announced that a double track will soon be built in the bypass of the city of Pando, which will connect with the double track of Route 8 that reaches Route 11. The alternative circuit should be complemented with the extension of the double track of Route 8. to route 9 and from there to Los Cardos, for which there is already a project, according to Rossi.

Then we moved to "La Toscana" to share a dinner and a heartfelt tribute to Hebert González, promoter of this project and which would be proud to see how everything was done on time and fulfilling the word.

NEW STRETCH WITH ASPHALT HiMA

Different experimental sections were carried out on Route 101 to evaluate the long-term performance of this new asphalt.

The new generation Hima asphalts (Highly Modified Asphalt) high content of polymers in its structure, allows for a significant increase in performance of the processed mixtures, used for traffic routes highest, or thickness substantially decreasing or way for implementing urban mixtures without losing workability conditions.

In the recent sections carried out on Route 101 together with the COLIER company, we achieved different combinations of asphalt in the base layer and in the tread layer and even with reduction of thickness in the sections with HiMA. We are happy to see that the behavior in the mixing plant and during its application is carried out at temperatures similar to the mixtures with AC 30. In the laying and compaction operations a very good densification is noted with just 2 to 3 passes of a smooth roller. The drivers were satisfied with the ease of the operations, especially in compaction.

The sections executed are located on Route 101 in front of the Science Park, between the roundabout of said park and the traffic lights of Colonia Nicolich. There a base coat was made in different alternatives. With the planned solution of 12 cm with AC30, then a section with HiMA in 12 cm and to finish a section in 10 cm. Then in the tread layer it was complemented by combining the previous ones with two asphalt, the AM3 foreseen by the project and the HiMA itself. This layer in single thickness of 5 cm.

Therefore we will have a test track with AC30 in base and HiMA in rolling, HiMA in all the thickness (and a section with reduced thickness) and HiMA in base and AM3 in rolling. This experience so close to our plant will allow us to monitor their evolution over time and draw conclusions.

We can anticipate, due to the results that we obtained in the laboratory and that were presented at the last Uruguayan Highway Congress, that great durability and performance are expected from the sections that have HiMA, which are also supported by experience worldwide.

Regarding the handling of this asphalt in the plant and on site, substantial improvements are achieved due to the low mixing and compaction temperatures, similar to those of conventional asphalt. We invite you to see some photos of the experience.

PERFORMANCE OF ASPHALT MODIFIED HIGH

the thesis of Ignacio Kröger Engineers and Carlos Pfeiff on the performance of highly modified asphalts (HiMA) was recently introduced.

Last July 4th fought against the Ing. Magdalena Pastorini, Ing. Arturo Forteza and Lic. Laura Luzuriaga with the final thesis which took more than eight months of intense work on a comparative study between the Hima the AM3 and AC30.

Continue read: REGIONAL MEETING IN BOLIVIA CIVIL ENGINEERING

In this thesis several technical papers to be presented at the 12th Congress of the Road Uruguaya and in the XX IBWC to be held in November in Mexico are released. Moreover it is performing a scaling himâ asphalt plant are preparing the experimental sections to assess their field performance in the long term.

FIRST TRANCHE OF ASPHALT IN URUGUAY HiMA

the first experimental section using highly modified asphalt (HiMA) was performed in Uruguay

The new highly modified asphalt (HiMA) developed by sion, He was executed by Necklace last August in the widening of Route 101. The section in question consists of 600 meters above prior to entering the roundabout junction Nicolich (direction Montevideo) outside lane. The aim of HIMA provide durability to asphalt, primarily because of its outstanding resistance to cracking and permanent deformation.

Continue read: DAY OF THE CHILD IN BARRIO COLONIA Nicolich

The original project consists of a black base with conventional AC-30 asphalt 12 cm on which a road surface with 5 cm AM3 is then applied. Colier was proposed, with the approval of the MTOP, 600 m replace the AC-30 HIMA of which 300 m in thickness was reduced to 10 cm (17% reduction).

Asphalt (17)

And extracted with witness samples of the asphalt plant will proceed to perform tests of dynamic modulus, and fatigue loaded in four-point beam wheel. With structural package information and research, it will proceed to use mechanistic empirical design programs, such as BackViDe (IMAE) to predict their behavior.

We appreciate the confidence Colier MTOP and apply technology to allow himâ for the first time on our roads. The research results will be presented at the XII Congress of the Road Uruguaya on 25, 26 and 27 September and the XX IBWC Mexico 25-29 November.

Credits: Rafael L. Martins

REGIONAL MEETING IN BOLIVIA CIVIL ENGINEERING

Bitafal group was invited to participate in the 1st Regional Meeting of Civil Engineering in the city of Santa Cruz de la Sierra, Bolivia.

It was held from 12 to 14 June at the Universidad Autónoma "Gabriel René Moreno" the meeting of Civil Engineering which was attended technical highlights of the region and where various issues were discussed from structures and pavements to sustainable mobility. It was organized by the University and the College of Civil Engineers of Santa Cruz.

Continue read: UNIFORMITY AND QUALITY

Among other topics discussed at the meeting they had presentations as "Current Status of Structural Policy", "Bolivian Seismic Design Guide", "Structural Concrete for Large Works" or "Sustainable Urban Mobility".

There was a significant presence of students in the last semesters of Civil Engineering which showed a very good technical level and interest in the issues.

Category Archives: HiMA Archives - Bitafal