Novel Nanostructured Aluminosilicates to develop Carbon Neutral Cement

Cement is responsible for approximately 5% of all anthropogenic CO2 emissions in the world. It is possible tocapture CO2 within cement via carbonation. The captured CO2 reacts with hydration products to form calciteminerals. Cement pastes naturally carbonates over time however this process is slow and is generally limitedto the exposed surfaces. The aim of this research was to accelerate the carbonation in the initial stage ofhydration to develop a high strength and less permeable material. Aluminosilicates were synthesised usingsol-gel technology by varying sol-gel parameters. Faujasite was used as a bench mark material due to its welldefined aluminosilicate structure and known capacity to capture CO2. This paper investigates the compatibilityof the tailored aluminosilicates with the cement and subsequent changes in the cement paste morphologymodified with 15% aluminosilicate used as a replacement for Portland cement. The studies have shown thatthe synthesized aluminosilicate (Na-T-10) have developed a denser morphology even at the initial stages ( 3and 7 day) indicating highly reactive nucleation sites that act as seeding agents for the production of porousC-S-H. Development of such highly reactive porous aluminosilicates has shown good potential for CO2 capture.High compatibility with cement paste is evident with the microstructural characterisation as though 15% ofcement was replaced with the nano structured aluminosilicate. The materials have shown the development ofC-S-H and portlandite which further suggests that these aluminosilicates are highly reactive in cement pastes