PSI - Issue 70

Hariharan kannan et al. / Procedia Structural Integrity 70 (2025) 658–665

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concrete, is a major obstacle in this endeavour. OPC production is recognized to have serious environmental effects, mostly as a result of the high emissions of greenhouse gases (GHG) by Mohamad et al (2022). With a notable 80 – 90% decrease in CO 2 emissions, geopolymer concrete presents a strong substitute for OPC-based concrete. by Ahmed and Mantawy (2025). By use of industrial waste such as rice husk ash, GGBFS, Fly Ash, CS, volcanic ash etc., aluminosilicate pioneers enable appropriate waste management and reduce the demand of cement by Singh and Singh (2019). The kind of aluminosilicate precursor is one of the primary factors distressing the geopolymer's strength. The cost of construction goes up because some aluminosilicate binders need to be heated to cure. According to Nguyen (2020) Alkali-activated materials, especially those derived from industrial byproducts like fly ash and granulated blast furnace slag, are becoming more and more popular among all the alternatives. Government laws have limited sand mining to reduce the exploitation of natural sand, which has affected the growth of building and raised expenses. A sustainable solution to these issues is the use of industrial waste as alternative resources by Kavitha (2021). Use of waste foundry sand (WFS) as a alternative of fine aggregates provides technical, economic and environmental benefits. These benefits are especially significant when considering sustainability in the building industry by Manoharan et al (2018). A least of 211 kg/m 3 of cement is typically utilized in the production of concrete paving blocks by Elchalakani et al (2017). As a result, alternatives ought to be discovered out to reduce ingesting of these natural resources. Moreover, a range of geopolymer products might be produced from the geopolymer including fire resistant panels, buried pipelines, lightweight GPC with fire confrontation and protecting capacity, geopolymer bricks and paving blocks. Paver blocks are solid, unreinforced blocks that have been used in building for many years and are suitable for outdoor use. However, given the growing mandate in developing nations and rising carbon emissions, linked with traditional paving blocks, the need to use alternate filler materials or cementitious are increasingly being studied today. Since cement is the main ingredient and is used widely in concrete paver blocks, its use needs to be decreased because it emits CO 2 by Tempa et al (2022). This study introduces a novel application of waste foundry sand (WFS) as a replacement for M-sand in fly ash-based geopolymer paver blocks. While WFS has been explored in concrete, its use in alkali-activated geopolymer paver block production is limited. This research fills that gap by evaluating its performance, offering a sustainable solution for precast paving applications. 2. Materials 2.1. Aggregates Coarse aggregate and M sand available locally in saturated surface dry condition, was employed to create a variety of samples with various mix designs. For casting the samples, the sand and gravel were chosen with properties conforming to BIS 2386-2019 (Part-1) and BIS 383 – 2016. The properties of gravel and sand used in mix design are calculated in Table 1. 2.2. Alkaline activator liquid (AAL) An Alkaline activator liquid of a solution of Na2SiO3 and NaOH is used to prepare samples with different mix designs. The characteristics of 97% pure sodium hydroxide pellets and sodium silicate liquid, which are acquired from nearby vendors, are displayed in Table 2. 2.3. Aluminosilicates In this study the basis material used for aluminosilicates is fly ash which was purchased form commercial suppliers and its properties are mentioned in Table 3 and Table 4. 2.4. Super plasticizer In accordance with IS 9103, a superplasticizer based on sulfonated naphthalene formaldehyde (SNF) was employed to increase the workability of geopolymer concrete.