High performance geopolymer concrete incorporating nano silica: experimental and economic assessment
Neha Sharma, Seema, Sagar Paruthi
Abstract
The environmental burden posed by traditional cement production has accelerated the search for sustainable alternatives in construction. This study explores the performance and cost-effectiveness of heat-cured geopolymer concrete (GPC) developed using heat curing at 60°C, ground granulated blast furnace slag (GGBS) with nano-silica (NS) as a partial replacement. GPC mixes incorporating 0%, 1%, 2%, and 3% NS by weight of GGBS were evaluated for mechanical properties, durability under aggressive chemical exposures (NaCl, Na2SO4, HCl, H2SO4), and water transport behavior through sorptivity, bulk diffusion, rapid chloride penetrability and absorption tests. SEM and EDX analyses were conducted to investigate microstructural changes and elemental composition. The results revealed that a 2% NS dosage yielded the highest strength value of 63.49 MPa (compressive), 7.5 MPa (split tensile), and 5.8 MPa (flexural) after 90 days of curing, improved durability, and a denser microstructure due to enhanced gel formation (C-A-S-H and N-A-S-H). Additionally, an economic assessment demonstrated that GPC with NS is more cost-effective than conventional OPC concrete due to the use of industrial byproducts and lower long-term maintenance requirements. These findings support the technical and economic viability of NS-modified GGBS-based GPC as a sustainable alternative to traditional concrete.