Project Status: Complete. Monitoring continued beyond the term of CSRP.
Project Participants: Alcoa, Department of Agriculture and Food WA
Project Leader: Rob Summers (Department of Agriculture and Food WA)
The use of coarse bauxite residue as a replacement for virgin mined sand in road construction is a key achievement for large scale use of mineral by-products. The physical evaluation of bauxite residue for use in the construction of a road was completed and the road prepared for construction. In the trial, more than 2,500 cubic metres of sand was extracted from bauxite residue and used as road base to widen the
Greenlands Road access to the new Perth Bunbury Highway near Pinjarra in Western Australia.
Once the road was completed in October 2009, monitoring of surface and ground water was undertaken to determine if there were any impacts from the use of bauxite residue compared to the impact of the"natural" (virgin mined) material. A detailed monitoring program was agreed. Monitoring of the drains also commenced prior to the road construction.
Initial construction data and subsequent testing was compiled into a final report. The results show that the ReSand® has proven to be an excellent embankment and subgrade construction material with strength properties that greatly exceed those of the normally used Perth sands. ReSand® is a strong improved subgrade or sub base material with a soaked Californian Bearing Ratio strength of 30 percent
or greater, only requiring the minimum design thickness of basecourse material. ReSand® may also potentially replace limestone as a pavement basecourse material covered with a thin layer of gravel. Water samples were taken in winter, when Perth receives more rainfall, and chemical analysis is expected to be finalised by October 2010. Finalisation of the report from Year 1, with included data from Year 2 as an addendum, is expected to be completed by December 2010 and delivered to the project participants.
For the next five years, pavement strength testing and visual inspections of the trial section of road will be conducted annually at the end of winter. After this time, the trial section will also be measured for roughness and rutting deterioration rates. The ultimate outcome will be for the ReSand® to be as strong as limestone for the construction of composite pavements, covered with thin gravel surfacing.
The research objectives are to report on the monitoring of the use of Red Sand™ in road construction, providing sufficient detail to determine:
This project represents the monitoring program and is linked to CSRP project "Demonstrations of Red Sand™" (129). Monitoring will be carried out by the project participants beyond the term of CSRP.