The Use of Recycled Crushed Concrete in Logan City Council Roads

Abstract

The recent urbanisation of cities, the rapid development and associated infrastructure has resulted in a significant increase in concrete construction and demand for natural aggregate. At the same time, urban renewal has meant that obsolete buildings and concrete structures are often demolished and replaced with new projects. The disposal of the resulting debris presents several issues. To reduce this concrete waste disposal, it has been recognised that such waste can be utilised as road base material instead of the commonly used natural aggregate. Using recycled concrete material in the construction of council roads has been identified as a cost-effective and eco-friendly solution by many experts in this field. This also extends the life of existing spoil sites in the long term. The technical paper aims to identify the possibility of using the recycled concrete material as a viable and cost-effective road-base material for low traffic volume roads and to develop a suitable specification to be used within the Roads Branches of Logan City Council (LCC). The current study is focused on the following points: • The viability of using recycled concrete as a road base material on low traffic (less than 10^6 ESA) roads. • Recycling the spoil economically through a contractor with the resources and appropriate machinery to crush the concrete appropriately. LCC’s Bega Road filling site at Kingston receives a large quantity of concrete waste material daily. The burying of this waste is not sustainable or economic. Burying concrete waste is not eco-friendly and has a tremendous impact on the carbon footprint of the council. A literature survey was carried out with the available specifications used in concrete recycling. In addition, a thorough search of published literature from the Department of Transport and Main Roads (TMR), Institute of Public Works Engineering Australia (IPWEA), other local government authorities, major road authorities (both NZ and Australia) and private contractors were reviewed. Additional information was collected from overseas studies, research papers published by Transport and Road Research Laboratory (TRRL-UK), Chartered Institution of Highways and Transportation (CHIT-UK), and articles published in India. Experts in public works engineering from IPWEA (NSW), Vic Roads, TMR and LCC's Road Infrastructure Delivery (RID) Branch were also contacted to gather information. After reviewing the data collected, LCC decided to adopt IPWEA (NSW) specification, with amendments, to use as our specification for recycled crushed concrete material. Following two successful trials, LCC’s Road Construction and Maintenance (RCM) Branch has gained valuable insight, and identified significant cost savings, whilst ensuring satisfactory compaction results. These findings will be described in the technical paper and may assist other councils and organisations in the field. During the 2 trials carried out by LCC, we have gathered valuable experience and look forward to sharing what we have learned about providing a cost-effective, eco-friendly, greener road base material for Logan City residents and road users.