Construction with Enrobés à Module Elevé (EME) on a section of the N3: the first full scale EME manufacturing and construction project in South Africa

The first full scale project to use EME (Enrobés à Module Elevé) – a French-developed high modulus hot mix asphalt technology – was carried out on a section of the N3 in Durban. EME was recently introduced to South Africa as a high performing asphalt base. The section of work, from Candella Road to Paradise Valley, carries a large volume of heavy vehicles. The purpose of the project was to mill and replace the existing deteriorated asphalt pavement. All paving was carried out during the night and over a year throughout all seasons. During the winter months the behaviour of the EME proved to be very sensitive to the cold conditions due to a combination of the low night temperatures and the EME mix components, specifically the stiff nature of the 10/20 penetration bitumen. A very low ambient temperature significantly reduced the construction window period. Additionally the EME was observed to cool more rapidly due to the cold pavement temperatures causing low compaction, especially on the longitudinal joints. Special techniques such as preheating the joints had been used with satisfactory success to overcome the problem. Another technique adopted was to create a “bump” at the longitudinal joint during the initial compaction using either a steel wheel roller or a pneumatic tyre roller which seemed to improve the compaction at the joint. During the rainy season the permeability of the mix was observed to become problematic when compaction was slightly below the minimum required density (i.e. 94% of the Maximum Theoretical Relative Density, MTRD). The compaction target density of 96 – 98% seemed to be more appropriate and was therefore adopted. A trial was also conducted in the slow lane using an EME mix with maximum stone size of 20.0mm that was constructed in one lift (i.e. 120mm thick). The trial showed that the larger stone-sized EME retained a large amount of heat, even after compaction was achieved, which had the potential to affect the riding quality if opened to traffic too soon (i.e. too hot). The project had provided unfavourable and challenging construction conditions for EME. There is an uncertainty as to whether or not the behavior of EME experienced on this project can be generalized at this point in time. Until more research can be conducted to verify the experience and observations made with EME, this paper serves to provide construction related guidance in future EME projects.

• Authors:
  • Rajkumar, S
  • Nortje, W
  • Conradie, R
  • Muthen, M
• Conference:
  • Conference on Asphalt Pavements for Southern Africa (CAPSA15), 11th, 2015, Sun City, South Africa
• Publication Date: 2015-8

Language

• English

Media Info

• Pagination: 12p
• Monograph Title: 11th Conference on Asphalt Pavements for Southern Africa: CAPSA15, 16-19 August 2015, Sun City, South Africa

Subject/Index Terms

• TRT Terms: Mix design; Pavement design; Pavement maintenance; Pavement performance; Seasons; Temperature
• Uncontrolled Terms: Pavement technology
• Geographic Terms: South Africa
• ATRI Terms: Mix design; Pavement design; Pavement maintenance; Pavement performance; Season; Temperature
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 01597149
• Record Type: Publication
• Source Agency: ARRB
• Files: ATRI
• Created Date: Apr 22 2016 11:17AM