The Re-use of Existing Bituminous Stabilised Materials for the Rehabilitation of National Route 7 - Case Study

The Re-use of Existing Bituminous Stabilised Materials for the Rehabilitation of National Route 7 - Case Study

Authors: Glynn Llewellyn1, Azni November2, Craig Bradley3
Conference: 13th Conference on Asphalt Pavements for Southern Africa
Date: October 15-18, 2023

1 Knight Piésold
2 Western Cape Government
3 Hatch Africa


Western Cape Government’s (WCG) Department of Infrastructure recognised the need to rehabilitate the existing N7 (TR11/1) in Cape Town between the Bosmansdam Interchange (km 2.00) and the Melkbosstrand Interchange (km 18.02). WCG tasked the project team with developing a cost-effective, sustainable solution that would minimize disruptions to the traffic and local community during the rehabilitation of the N7. In response, an innovative approach to reprocess the existing bitumen stabilised material (BSM), which behaved somewhere between a published BSM and cement stabilised material, as well incorporating the milled off asphalt for use in the base layer was proposed. The proposal effectively meant re-processing the base material for a third time thereby providing a “third-life-cycle rehabilitation”.

This paper will focus on the materials investigation undertaken on the project that led to the design proposal, design process followed at the time, pavement life cycle evaluation and relook at the design post publication of the TG 2, 2020 BSM transfer function.


Download the full paper.


Recent Insights

February 2024
Empowerment and Resilience
January 2024
Balancing Act: Water Usage Management Vital for a Sustainable Future
January 2024
A Difficult Balance Between Engineering, Environmental, Social and Economic Aspects
November 2023
Knight Piésold Commences with the ESIA for Haib Copper
November 2023
Insights from the Compilation and Critical Assessment of Breach and Runout Characteristics from Historical Tailings Dam Failures: Implications for Numerical Modelling
November 2023
Earthquake-induced Deformation Analysis of a TSF Undergoing Tailings Reprocessing
November 2023
Case Study: Approach to Determining the Risk Mitigation Priority of a Historic TSF in North America
October 2023
Data Management and Insights for Effective Tailings Storage Facility Management
October 2023
The Role of Sensitivity Analysis in Selecting Dam Breach Parameters
October 2023
Influence of Increased Confining Stress on Undrained Behavior of Tailings: A Case History at the Candelaria Mine
September 2023
Transición energética para gerentes de mina
August 2023
Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú
July 2023
Selection of Soil Shear Strength Parameters Based on Integrated In Situ Tests, Lab Tests and Numerical Calibration Approach
June 2023
Leveraging Knowledge and Experience of a Well-Formed Independent Tailings Review Board to Enhance Tailings Facility Safety
May 2023
Is the Implementation of Dry Stacking for Tailings Storage Increasing? A Southern African Perspective
February 2023
Canadian Consulting Engineer's Lifetime Achievement Awards: Jeremy Haile
February 2023
Geotechnical Characterization of Collapsible Salty Sands Subjected to Monotonic and Cyclic Loadings – A Case Study for Areas with High Seismicity
November 2022
Application of the 3D Limit Equilibrium Method in Tailings Dam Breach Analysis
November 2022
Evaluation of Tailings Behaviour for Dam Breach Assessments