This paper presents the results of laboratory and field experiments conducted for a major ground support operation to assess the performance of wet-mix shotcrete incorporating various chemical admixtures. The project had an alkali-silica reaction (ASR) risk due to the aggregates available in the region being reactive. Therefore, a customised mix design was prepared and specialty chemical admixtures formulated with the latest available technologies were selected to mitigate the ASR while meeting the project specifications. The performance of the proposed system, which contained 25% fly ash and 0.8% of pozzolanic-based rheology control agent, was compared with the reference mix containing 8% silica fume as well as the target performance limits of the project. Test results showed that, when compared to the reference mix, the proposed system improved the shotcrete performance by reducing the ASR potential, increasing early-age strength, enhancing sprayability by increasing the stickiness and cohesiveness, and meeting later-age strength, toughness, and durability requirements.

There is an ever-increasing amount of waste glass generated worldwide that is currently sent to landfill, and has a high potential for re-use. In Australia alone, the consumption of glass is 1.36 million tonnes, with the state of New South Wales producing the highest amount. Traditional landfilling and stockpiling of waste glass are not an environment-friendly solution, and the re-use of waste glass has become an important research topic in Australia and worldwide. This Project employs an experimental study to estimate waste glass re-cycling in shotcrete production. Mechanical strength and fracture properties of the new mix designs are compared against the controlled mixes at 0% waste glass inclusions. From the results, no impaired performance was recorded by substituting sand with crushed waste glass even at a high percentage ratio of up to 100%. While further research is needed, the promising early results highly encourage the applicability of crushed waste glass for sustainable shotcrete design, a topic that is yet relatively under-researched.