Long-term performance evaluation of slag-cenosphere geopolymer mortar

In recent years, geopolymer formulations have emerged as environmentally sustainable alternatives to traditional concrete due to their potential to mitigate environmental impact and aid in waste management. This research investigates the effect of cenosphere on the mechanical and durability properties of ground-granulated blast furnace slag (GGBFS)--based geopolymer. In the study, different replacement percentages of cenosphere (0 %, 25 %, 50 %, and 75 %) are used. The resulting geopolymers are examined for mechanical strength, elastic modulus, drying shrinkage, and different durability properties such as sulfate attack resistance, carbonation, and fire resistance. Results indicate that the inclusion of cenospheres in GGBFS-based geopolymer adversely affects the mechanical properties. However, up to 50 % substitution of cenospheres maintains mechanical strength above those of ordinary portland cement. Regarding durability assessments, cenosphere addition improves sulfate attack and fire resistance, while increasing drying shrinkage and carbonation depth. Due to the higher carbonation depth, the significant CO2 capture observed in cenosphere-based geopolymers highlights their potential to reduce net CO2 emissions in certain applications. These findings suggest the potential of GGBFS-cenosphere geopolymer as a viable, sustainable non-structural construction material. •Geopolymers with 25 %, 50 %, and 75 % cenosphere at 6 M NaOH were investigated.•Water curing significantly influenced the mechanical properties of geopolymers.•Geopolymers with up to 50 % cenospheres exhibited better acid resistance than OPC.•Geopolymers with high cenosphere content showed enhanced thermal resistance.•Increased cenosphere incorporation accelerated carbonation, suggesting CO2 benefits.