Confirmation of Candidature - A Proposal to Study the Development of Sustainable and Environmentally Friendly Grout Product for Geotechnical Industry Using Plastic Waste

Anchors are widely used in the construction and mining industry in Australia and around the globe. Whilst there is substantial supplier data available, the anchors are typically specified using proprietary grout mixes depending upon the application. Many studies have been conducted to determine the performance of anchors in various customised substrates and using amended grout in the recent years.

In today's modern world clean and green technologies are attracting a lot of attention. Once such initiative is substituting additives in grout partially with by-products or waste materials like Fly Ash, Blast furnace slag, Colemanite, Simektit, Perlite, Basalt dust, Coal dust, and Metakaolin. Such materials (deposited into landfills) without further consumption consume more space than necessary, not to mention that they bring adverse environmental impacts, such as leaching and groundwater contamination. As such, green technologies have become essential and should be promoted. In recent years, using such waste materials in different fields, such as the concrete mixture, has gained more interest. According to the finding and results, using these by-products has provided better concrete and mortar properties.

A waste material, that is found in abundance, is plastic. Plastic has many valuable uses and has become an essential part of our lives. Humans are mostly using plastic products for single use, and these are disposed of subsequently, resulting in severe environmental implications. Millions of plastic bottles and bags worldwide are of single use and majority of these products are designed to be used only once and are subsequently disposed. Therefore, plastics are rapidly growing segment of the municipal solid waste. Plastics are found in non-durable products such as bags, cups, utensils, medical devices and a variety of household items. The plastic food service items are generally made of clear plastic or foamed polystyrene, while trash bags are made of high-density polyethylene (HDPE) or low-density polyethylene (LDPE). Most of the countries in the world are concerned that plastic pollution has become one of the most pressing environmental issues, as rapidly increasing production of disposable plastic products overwhelms the world's ability to deal with them. Whilst plastic pollution is most visible in developing nations, where the garbage collection systems are often inefficient or non-existent, the low recycling rates in the developed world are also suffering when it comes to collection and management of used plastics. In an attempt to address this environmental issue globally, studies are being carried out to use waste plastic in construction industry. For example, some suppliers in Australia are converting waste plastic into valuable construction material and thereby reducing environmental pollution. Some manufacturers claim that substituting 10% recycled plastic for natural aggregates results in negligible impact on density and compressive strength of concrete. This study will look into substituting some percentage of waste plastic in cementitious grout and assess the performance of anchors and compare against conventional grout.

Whilst there is enthusiasm of developing new grout products, we know that the failure of bolt reinforcement in conventional systems still occurs. Therefore, it is very important to understand the failure mechanisms that can help in studying modified grout. There are essentially five different failure types of bolting, namely bond failure at the bolt/grout interface, failure within the grout column, relative slippage at the bolt/rock interface, failure within surrounding rock mass, and breaking of the bolt because of shear resistance. Based on the load transfer concept, the material used to bond the bolt to the rock mass surrounding the borehole (which is the cementitious grout) provides the mechanism for transferring force between the rock mass and the bolt through shearing forces within the grout. 

For more information, please email the Graduate Research School or phone 0746 311088.