PSI - Issue 70

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

314

from local supplier of Mahendergarh, Haryana with the fineness moduli of 3.10, 3.25, and 2.56 respectively. Anhydrous Sodium metasilicate is obtained from Exemplar, New Delhi, was used as a solid alkali activator; it contains 50.50% Na₂O and 49.82% SiO₂, with a SiO₂/Na₂O ratio of 1:0.99, offering a safer and more convenient alternative to liquid alkaline solutions for GPC production.

Table 1 Chemical composition of GGBS from JSW Cement Ltd.

CaO

SiO₂

Al₂O₃

MgO

SO₃

Fe₂O₃

MnO Cl

LOI

CaO

Chemical Component

32.0 32.5

19.5

7.96

0.26 1.09

0.66

0.004

0.16 32.0

Content (%)

Table 2 Physical Properties of GGBS

Property

Specific Gravity

Initial Setting Time

Final Setting Time

Fineness (m²/kg)

Measured Value

2.8

58 minutes

8 hours

400

Table 3 Properties of Coarse Aggregates

Property

Fineness Modulus

Aggregate Impact Value

Crushing Value

Los Angeles Abrasion Value

CA

3.25

15.2%

12%

26.2%

2.2. Optimized approach for designing Geopolymer Concrete (GPC) Even though significant advancements in (GPC), yet standardized mix design methodology for making geopolymer concrete remains a major challenge. Researchers have explored too many combinations of chemical activators — especially for NaOH and sodium silicate — along with many industrial by-products, and other ingredients like CA and FA. However, the complex interactions among variables such as activator concentration, binder type, by product proportions/ ratios, and curing conditions often lead to inconsistent results, making GPC design methodology more complicated than conventional concrete (Montes et al., 2013). While various empirical approaches have been proposed by Lloyd & Rangan, 2010; Anuradha et al., 2012; Ferdous et al., 2013, a universally accepted method for making GPC is still lacking. 2.3. Ingredient proportions for the production of Geopolymer Concrete In this GPC was prepared by following IS codal provisions as discussed above. In this, CA, FA and ASM were mixed first in pan mixer in dry condition for 2 – 3 minutes and then water and superplasticizer were added, and mixing continued for another 3 – 4 minutes to achieve uniform and homogeneous mix. Workability was checked using the slump test (IS 1199:1959).

Fig. 3. (a) Mix preparation; (b) Sample curing; (c) Sample testing.