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Investigating the use of nano-modified bitumen to treat recycled asphalt

Jannie Hattingh - AECOM, Riaan Burger - AECOM & Prof. Kim Jenkins - Stellenbosch University


SPEAKER PRESENTATION

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Abstract

The growing worldwide implementation of pavement recycling and bitumen stabilisation technologies has led to an increased need for reliable performance evaluation techniques for bitumen-stabilised materials (BSMs). Laboratory compaction has seen an evolution in the equipment and methods used, with the objective of achieving laboratory compaction that adequately simulates field compaction. While using compaction equipment and methods for granular materials may seem to be the sensible approach to achieving the required compaction of BSM specimens, the following challenges were faced:

  • Inadequate energy of existing equipment to achieve required specimen densities
  • A large variability of particle sizes created by variability in composition of RA used for BSM mixes, leading to inconsistent results on standard specimen sizes with large aggregates
  • Inconsistent specimen densities achieved from existing compaction methods.

This paper describes the stages in the evolution of laboratory compaction equipment for BSM specimens in trials that were conducted over a 10-year period. Test results from the trials show a great reduction in variability of the specimen densities. An additional benefit was an improvement in ITS results, adding to the reliability of the performance evaluation of BSM mixes.

About the Authors

Thembalethu Mhlanga holds a BSc in Civil Engineering which she completed at Wits University in 2018. She works as a Civil Engineer in the Pavement and Materials Department at ROMH Consulting. Since completing her degree, she has acquired experience in road condition assessment, pavement design, materials sourcing and design and contract administration for new projects, periodic maintenance and road upgrade projects. She has also been extensively involved in SANRAL Routine Road Maintenance projects for various national roads.

Wynand van Niekerk is Managing Director of BSM Laboratories. He started working in the soils laboratory industry in 2002 as a field technician at LABCO in Port Elizabeth and joined Contro Lab in 2005 as Laboratory Manager on several site laboratories in the Eastern Cape. In 2009 Soilco Material Investigation approached Wynand to join BSM Laboratories focusing on bitumen stabilised material testing. His contribution to the revision and replacement of TG2 2009 with the TG2 2020 document has been vital to the industry.