Influence of Waste Circuit Board Non-Metallic Powder on Properties of Alkali-Activated Slag/Fly Ash Cementitious Material.

A novel alkali-activated slag/ fly ash cementitious material was prepared by incorporating 0% ~ 25% (mass fraction) waste circuit board non-metallic powder (NMP). The properties of this new material were evaluated, including its mechanical strength, hydration heat release, phase composition, and pore size distribution. The microstructural features were also analyzed. The results indicate that the addition of NMP not only reduces the workability and cumulative heat release of cementitious material, but also slightly reduces its 7 and 28 d compressive strength. When the NMP content is less than 15% (mass fraction), the 28 d flexural strength of cementitious material is positively correlated with the NMP content due to the presence of glass fibers, resulting in a maximum increase of 55. 5%. Incorporating NMP reduces the proportion of pores with diameter between 100 nm and 1 000 nm, while improving the proportion of micropores with diameter below 100 nm, leading to an overall increase in total porosity. The resin particles in NMP are tightly bound to the cementitious material matrix, filling the voids between the fibers and the matrix. The addition of NMP does not affect the types of hydration products in the original cementitious material. [ABSTRACT FROM AUTHOR]