Preparation of Ecotype Cementing Material: Alkali-activated Modified High Carbon Content Fly Ash / Granulated Blast Furnace Slag Binder

摘要

In the presence of some modifiers, high carbon fly ash (HCFA) is clacinated at 700~900°C. The modified HCFA is mixed with granulated blast-furnace slag (GBFS) and an activator, and ground to form an ecotype cementing material. The optimized formulation of the cementing material is obtained with the aid of orthogonal array technique: slag-47%, Modified HCFA-47%, activator-6%. The "partial super-fine grinding process" is adopted to improve the characteristics, I.e. before mixing, 85 percent of the product is ground to Blaine fineness of 3,500cm2 /g, 15 percent further ground to around 5,000 cm2 /g . The compressive strength of the cement mortar of 3d is up to 19.6 Mpa and flexural strength 5.0 Mpa. The compressive strength of 28d is up to 51.0 Mpa and flexural strength 8.6 Mpa. The hydration products, studied by SEM and XRD, are mainly ettringite and C-S-H (I).