# Durability of High Volume Glass Powder Self-Compacting Concrete
## 1 Introduction  
The durability of concrete can be defined as its ability to resist weathering action, chemical attack, abrasion and any other mechanism of deterioration while preserving its original form. The degree of deterioration is strongly related to the resistance of the cover layer to transport mechanisms, such as permeation, absorption, and diffusion of gas and liquid [1]. The use of supplementary cementitious materials (SCMs) in concrete helps in increasing resistance towards most of the durability related issues. The benefits of using silica fume, fly ash, slag and calcined clay has been widely demonstrated [2; 3; 4; 5; 6]. The use of waste glass powder as a potential SCM has also received significant interest in the last two decades [4; 7; 8; 9]. The early age compressive strength for concrete containing glass powder is generally lower than the equivalent PC concrete. Similar strength values for glass powered concrete however have been reported at 90 days for replacement levels of up to 30% [10; 11; 12]. Further grinding of the glass powder can reduce the average particle size and help to offset the lower early age compressive strength [10; 13]. Increasing the fineness and proportion of glass powder however has been shown to negatively affect the workability of the mix [14; 15]. The irregular angular shape of the glass particles is responsible for the increased water demand compared to PC mixes. Numerous studies have reported the implications of using glass powder on the fresh and mechanical properties of concrete; however, limited information is available on the durability performance of such concrete. The rapid development in the infrastructure sector around the world is expected to increase the demand for cement from current the levels of -4 billion tonnes to -6 billion tonnes by 2050 [16]. The large carbon footprint associated with the cement industry makes it imperative to develop sustainable solutions that promote the judicious use of materials and increased service life of concretestructures with minimal maintenance. The global supply of waste glass represents approximately \(\sim\)3% (130 million tonnes) of the total cement consumption [17]. While this a relatively small proportion it does provide a possible option for diverting a waste stream from land fill and may be of particular benefit in areas that have limited supplies of more traditional SCMs such as fly ash, slag or silica fume. Establishing the durability characteristics of glass powder therefore is imperative to ensure its usage in the concrete industry together with the potential economic and environmental benefits. Concrete containing glass powder is often investigated for susceptibility of alkali silica reaction (ASR) due to the presence of high alkali contents associated with glass. Research has shown that the ASR could be mitigated by using finely ground glass powder in concrete typically smaller than 75 \(\upmu\)m [8; 11; 15; 18]. Moreover, using glass powder as a replacement for cement could help in reducing the deleterious expansion associated with ASR. [PERSON] and [PERSON] (2006) [15] measured the permeation characteristics of glass powder concrete mixes using rapid chloride penetration test (RCPT). A lower chloride penetrability was reported for glass mixes as compared to the control mix. [PERSON] and [PERSON] (2012) [19] also reported lower total charge passing through glass concrete. This property was attributed to the refined pore structure resulting from the densification of microstructure due to the pozzolanic reaction of glass. [PERSON] et al. (2018) [20] however, reported higher RCPT value and higher chloride diffusion coefficient measured using NT 492 for concrete containing 20% glass powder at 28 days as compared to PC. The chloride diffusivity of the glass powder mixes was found to decrease as the hydration progressed. [PERSON] et al. (2017) [21] showed a reduction in permeability and increase in electrical resistivity of mortars with an increase in the cement replacement level for fine glass powder particles.