Loudon International is an independent consulting engineering firm registered in the Republic of South Africa. The firm (formerly AA Loudon Partners) actively participates in pavement rehabilitation projects, worldwide, specialising in pavement design and the application of recycling and bitumen stabilisation technology.

The firm achieves this through engagement with industry organisations, client bodies, consulting engineers and contractors to promote and utilise recycling as the preferred approach to rehabilitating distressed pavements.  Assistance is provided in assessing specific projects, designing a recycling solution and in the construction activities where material is recycled from existing pavements.This is essentially a “technology transfer” service whereby local engineers work with and learn from the Loudon International specialists assigned to the project, allowing them to become acquainted with the technology so that they can continue unassisted with future work.

Since 1996, Loudon International has been actively involved in pavement rehabilitation projects on all continents (except Antarctica) allowing their engineers to amass a wealth of experience.  The map below indicates the extent of their exposure to projects that fall under almost all environmental conditions that can be encountered.

Two award-winning projects can be singled out:

  • In 1997, the 386km length of road linking the outside world to the new Shaybah Oilfield in eastern Saudi Arabia was upgraded to blacktop standards by recycling / stabilising the gravel wearing course with foamed bitumen. The entire project was successfully completed in just six months using three recycling trains that worked continuously for 24 hours per day.
  • In 2011, a section of the truck lane on the heavily trafficked Ayrton Senna Highway between the cities of São Paulo and Rio de Janeiro was rehabilitated using bitumen stabilisation technology. Working at night, the existing pavement was removed to a depth of 35cm and replaced immediately with recycled material treated in-plant with foamed bitumen. All work was carried out in a 7-hour working window and the lane opened to truck traffic at dawn.  This process was subsequently applied to rehabilitate all truck lanes on this 50km long highway concession (EcoRodovias).

In addition, numerous projects have been undertaken in the USA between 1997 and present, assisting the various State Highway Departments and contractors with recycling projects (primarily in Alaska, California, Maine, Ohio and Virginia).  Since 2001, Loudon International has been an Affiliate Member of the Asphalt Recycling and Reclamation Association (ARRA), an American industry association concerned with recycling.

Contribution to BSM technology

Loudon International holds a major shareholding in BSM Laboratories (Pty) Ltd, a commercial laboratory in Durban, South Africa, that specialises in testing bitumen stabilised materials (specifically mix designs).  Using these laboratory facilities, relevant recycling and stabilisation R&D projects are undertaken in co-operation with the University of Stellenbosch and other research institutions.

Loudon International was responsible for compiling the 1st Edition of the Wirtgen Cold Recycling Manual in 1998 that has become the primary reference document for this technology.  Since then, Wirtgen GmbH (Germany) has retained their services as principal author for all revisions and updated editions.  As a consequence of the increase in demand for recycling technology and the amount of relevant research recently undertaken, the decision was taken during 2012 to split the Manual into two separate books: Recycling Technology and Recycling Application.  (The Technology Manual was published in August 2012 whilst the Application manual is scheduled to be released during 2020.)

Engineers from Loudon International were invited to co-author the Asphalt Academy publication TG2, Guidelines for the design and construction of bitumen stabilised materials.  The First Edition was published in 2002, the revised Second Edition in 2009 and the Third Edition (total rewrite) in 2020.  (The Asphalt Academy is a South African industry body that is funded jointly by SABITA and the CSIR.)

During 2012, engineers from Loudon International were responsible for compiling draft in situ recycling specifications for the South African National Roads Agency Limited (SANRAL).

BSM recycling education

Loudon International engineers are continuously engaged worldwide in recycling promotion and education activities, including:

  • Invited lectures at selected universities (e.g. Stellenbosch and TU Delft)
  • Industry seminars focusing on pavement rehabilitation by recycling
  • Technical courses (e.g. those run by the South African Road Federation)
  • Presentation of papers at major conferences (e.g. TRB, ISAP, CAPSA, ARRB, etc.)
  • Training courses for the application of recycling technology (run in association with Wirtgen GmbH)

Our focus

Loudon International is focused on assisting engineers who are sincere in promoting construction methods that are less damaging to the environment than those normally used to rehabilitate pavements.  Recycling material from existing pavements and the use of bitumen stabilisation has been shown on numerous projects, worldwide, to be extremely cost effective (especially when life-cycle costs are considered).  In addition, recycling and bitumen stabilisation significantly reduces energy consumption and the related carbon footprint emanating from construction and maintenance operations during the service life of the rehabilitated pavement.

Key strengths

Recycling pavement materials, pavement investigations, pavement rehabilitation, pavement design, bitumen stabilisation, foamed bitumen, construction using recycled material.