PSI - Issue 70

Yankesh et al. / Procedia Structural Integrity 70 (2025) 311–318

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1. Introduction From the time of independence, India’s infrastructure has rapidly developed, driving economic growth in our country and improving living standards. Major investors invest in transport and urban initiatives like Smart Cities, which have enhanced connectivity and sustainability. (Singh, R et al., 2020). And the heart of this progress is the cement industry, which started in 1904 in Tamil Nadu and now ranks second globally, producing over 200 million tonnes of cement annually. (Ravi, B et al., 2022). Policies reform in the 1980s – 90s inflames growth, with domestic use exceeding 95% of output (Bapata J.D et al., 2007). However, this expansion of cement production significantly contributes to CO₂ emissions in atmosphere and resource depletion, as nearly one tonne of CO₂ emitted as per tonne production of cement by any method. It was observed from the previous study that 25% demand of cement is increased each decade, the expected outcome has determined from 30 million tonnes in 1980 to over 370 million by 2025 shown in fig. 1.(a)&(b) (Yeonbaekim et al., 2002), change environmental challenges. Davidovits, first who developed (GPC) in 1970s, and offers a cement-free, eco-friendly alternative to conventional concrete. Using fly ash, GGBS, RHA and slag with activated alkaline solutions, GPC reduces dependence on raw materials and industrial production process (Aleem A. et al., 2012; Zhao J. et al., 2021). The challenges like solution preparation and mix design still exist, geopolymer concrete (GPC) offers comparable strength to conventional concrete while significantly reducing GHG (greenhouse gas) emissions, making it a promising solution for sustainable infrastructure. (Parathi, S et al., 2021).

Fig. 1. (a) Cement production in India over the year; (b) CO 2 emission over the years.

The study showed that conventional concrete mix design requires significant skill and precision to achieve the right proportions. In contrast to this, the development of GPC offers a simpler alternative solution helping to reduce these challenges while also cutting down CO₂ emissions — making it both easier to use and more environmentally friendly. 1.1. Literature study on GPC In 1970, Davidovits discovered an alternative material to cement called Geo-polymer with 0% CO 2 emission. GPC activated with a solution of KOH (6 – 8 M) gained strength of 40 – 120 MPa under ambient conditions (Nazari et al., 2011). The comparison in fig. 2. (a) shows that GPC is more durable and cost-efficient as compare to conventional concrete. 80:20 and 60:40 ratios of fly ash and RHA in the mixes attain strength of 49 MPa and 60 MPa under heat curing (80°C) When temperature is increased from 60°C to 90°C simultaneously strength is also increased (Detphan & Chindaprasirt, 2009). The practical shape GGBS is angular in shape as shown in the fig. 2. (b). Its performance depends on factors like binder type, activator molarity, and curing conditions. From past studies it was observed that a 13M of NaOH solution can utilize 100% of GGBS at ambient curing (Ganesh A et al., 2020). When low-calcium fly ash with 14M of NaOH and 2.5:1 ratio of sodium silicate to NaOH showed 67.6 MPa strength at 7 days; workability is improved up to 2%. However, the heat curing stable the results at 24 hours (Hardjito et al., 2004). Another mix with