PSI - Issue 70

Ravi Malik et al. / Procedia Structural Integrity 70 (2025) 682–689

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granulated blast furnace slag (GGBS) are examined by (Gupta et al., 2021). 100% GGBS and a 50% GGBS/50% fly ash blend, activated with a 3:2 ratio of sodium silicate and sodium hydroxide, were the two mix types that were examined. At 7 and 28 days, mechanical characteristics (compressive and split tensile strength) were measured, and at 28 days, water absorption was used to gauge durability. The findings indicated that strength and durability were improved by increasing the dosage of superplasticizer. The 50% GGBS/50% fly ash mix with 3% superplasticizer showed the lowest water absorption (2.40%) and a 27.6% increase in tensile strength, while the 100% GGBS mix with 3% superplasticizer had the maximum split tensile strength and compressive strength (40.2 MPa, +10.4%). By decreasing porosity, the polycarboxylic ether-based superplasticizer (Glenium Sky 8630) increased density and workability. The study comes to the conclusion that GGBS-fly ash geopolymer concrete's potential as a sustainable building material is increased by optimizing the dosage of superplasticizer. The mechanical characteristics of environmentally friendly geopolymer concrete (GPC), a sustainable substitute for Ordinary Portland Cement (OPC), are examined by (Thapa et al., 2024). Research on GPC formulations using fly ash, ground granulated blast furnace slag (GGBS), metakaolin, and silica fume activated with 14M and 16M NaOH solutions is being carried out by Sandeep Thapa. Important results show that compressive strength is improved by greater NaOH molarity and curing temperatures (60°C and 100°C); the GP1 mix achieved 43.6 N/mm² (16M, 28 days), while the GP3 mix achieved 35.2 N/mm² (14M, 7 days). Through the production of calcium silicate hydrate gel, GGBS content increases strength; yet, because of particle interlocking and viscosity, workability declines as GGBS and silica fume levels rise. While ambient curing produces poorer results, optimal curing at 100°C increases early strength. In addition to highlighting GPC's potential to lower carbon emissions, the paper suggests mechanized mixing and more microstructural research for useful, affordable applications. Through the optimization of GPC mix designs for high performance and environmental benefits, this work promotes sustainable building despite lab-controlled restrictions. To examine the properties of environmentally friendly engineered geopolymer composites (EGC) (Tahwia et al., 2024), partially replaced (10 – 50%) ground granulated blast furnace slag (GGBFS) with sustainable pozzolanic waste materials — rice husk ash (RHA), granite waste powder (GWP), and volcanic pumice powder (VPP. Through SEM examination, the study investigates their effects on workability, unit weight, cohesive, tensile, and flexural mechanical strengths, water absorption, porosity, residual compressive strength at high temperatures (200 – 600°C), and microstructure. The findings indicate that 50% VPP increases workability by 38.5%, but RHA and GWP decrease it by up to 23.1% and 30.8%, respectively. The maximum mechanical strengths and thermal resistance are attained by optimal combinations (30% RHA, 20% GWP, and 10% VPP); nevertheless, compressive strength often declines with increasing substitutes. Water absorption and porosity decrease with VPP (up to 24.7% and 22.6%), but increase with RHA (up to 106.1% and 75.1%) and GWP (up to 23.2% and 18.6%). SEM shows that the control and VPP-10 combinations have denser matrices, while RHA-30 and GWP-20 have more porosity. With ideal ratios balancing performance and environmental friendliness, the study indicates that these waste materials can improve EGC sustainability and suggests more durability research. The key findings on GPC’s Mechanical properties are shown in Table 1 . Table 1. Summary of Key Research Findings on the Mechanical Performance, Sustainability and Practical Implementation of GPC Study Strength Sustainability/Practical Applications Curing & Workability Hewayde et al. (2006)

50% OPC replacement with geopolymer cement increases 28-day strength by ~50%; recommended for sewer pipes. GPC achieves 40–90 MPa, similar to OPC, with better tensile strength, less creep, and shrinkage. 12M NaOH yields 47.5 MPa at 91 days; tensile-to compressive strength ratio (f_sp = 0.17(f_c)^0.3) similar to OPC. Additives (GGBFS, OPC, CH) yield 1-day strength of 3.6–10.5 MPa, 28-day strength of 26–58 MPa;

emitting up to 90% less CO₂ and using 50% less energy than OPC. It enhances concrete sewer pipe durability against sulphuric acid, suggesting potential for full-scale manufacturing applications. Reduces CO₂ emissions as a sustainable OPC alternative, suitable for structural use.

cured concrete at 23°C, >95% humidity for 7–120 days, A water-reducing admixture improved workability (w/c 0.35). Heat curing at 60°C for 24 hours optimizes strength; ambient curing gains strength slowly. is recommended for precast applications. Ambient curing at 23°C; workability maximized at 550–650 kg/m³ binder content. Curing at 60°C

Rangan (2009)

Ryu et al. (2013)

Eco- friendly material reducing CO₂ emissions, suitable for precast products; needs more data for broader use.

Nath et al. (2015)

Cement-free cast-in-situ applications, enhancing practicality and sustainability. GPC for