Evaluation of Elastic Modulus of Crushed Stone Base Layers for Compaction Control

Jonathan Richard Geldenhuys1, & Philip Paige-Green2
1VKE Namibia (Part of the SMEC Group), Namibia
2Department of Civil Engineering, Tshwane University of Technology, South Africa
DOI – http://doi.org/10.37502/IJSMR.2022.51002

Abstract

Construction of high-quality crushed stone layers is referred to as “an art and one that is not profusely found today”. Conventional acceptance control procedures only confirm densification of the layer and other fundamental material properties with no direct measurement of strength. As a result of this there appears to be a missing link between design requirements and acceptance control. Slushing is required during the construction process to lock up the aggregate, ensuring stability and a good distribution of the fines through the layer. This study endeavours to confirm whether there is a significant difference in the Elastic Modulus of crushed stone layers before and after the slushing process and to investigate cost-effective and appropriate means of controlling this. Preliminary results suggest that poor workmanship can be clearly identified and an increase in Elastic Modulus can be confirmed following the right construction methods and procedures.

Keywords: Crushed Stone Bases, Slushing, Elastic Modulus, LWD, Sustainable Infrastructure.

References

  • EMERY, SJ. 1981. Prediction of Moisture Content for Use in Pavement Design. PhD Thesis, University of the Witwatersrand, Johannesburg.
  • KLEYN, E. 2012. Successful G1 Crushed Stone Basecourse Construction. In: Proceedings of the 31st Southern African Transport Conference, 9 – 12 July, 2012, Pretoria, South Africa [Online]. Available from: http://hdl.handle.net/2263/19992 [Accessed: 5 July 2019]
  • SOUTH AFRICAN PAVEMENT ENGINEERING MANUAL. 2013. Chapter 10: Pavement Design, Pretoria, The South African National Roads Agency LTD. (SANRAL)
  • THEYSE, H.L., DE BEER, M. & RUST, F.C. 1996. Overview of South African Mechanistic Pavement Design Method. Transportation research Record 1539, Division of Roads and Transport Technology, CSIR, Pretoria.