Impact of Graphene Nanoplatelets in Developing a Low-Calcium Fly Ash and GGBS-Based Geopolymer Binder Concrete

This study explores a single-component geopolymer concrete (GPC) formulated with a blend of low-calcium fly ash and ground-granulated blast furnace slag (GGBS). The objective is to develop a Portland cement-free GPC with minimal energy-intensive alkali activators, resulting in a general-use composite with a compressive strength exceeding 10 MPa. Additionally, the study explores the effects of specific grade graphene nanoplatelets (GnP) on GPC at the nanoscale. The research includes testing of fresh properties, compressive strength, water absorption, and chloride resistance. An optimized GPC mixture achieved compressive strengths of 16.16 MPa at 8 days and 18.31 MPa at 34 days. GnP demonstrated promising enhancements to GPC, including a 54% increase in strength and a 13% reduction in water absorption capacity. GnP exhibits notable resilience to efflorescence, with a positive influence on the mechanical properties of GPC.