The use of ordinary Portland cement (OPC) in the production of concrete lead to serious environmental issues and high energy consumption. Moreover, a substantial amount of natural resources are consumed by OPC production. This study develops novel cementless one-part alkali-activated composites consisting of ground granulated blast furnace slag (GGBS) and recycled concrete powder (RCP) activated by sodium metasilicate-anhydrous. The setting time, rheology, and compressive strength of slag based alkali-activated paste mixes activated with sodium metasilicate-anhydrous at 8% and 12% ratios were investigated in the present paper. The RCP ratio and solid activator dosage significantly influenced the fresh-state properties of geopolymer mixtures. The paste mixes containing 8% activator showed prolonged setting times compared to those with 12% activator. In addition, an increase in the RCP ratio prolonged the initial and final setting times of the paste mixes. Increasing the RCP ratio increased yield stress and decreased plastic viscosity. Both yield stress and plastic viscosity were marginally increased due to the increase in the activator ratio. The highest compressive strength was observed in the L0-12 mix as 92.33 MPa at 28 days. On the other hand, the incorporation of RCP (L50-12) achieved compressive strength of 60.81 MPa at 28 days which is suitable for most of the civil engineering applications. ORCID ID: 0000-0003-3257-8256
Keywords: Blast furnace slag, Alkali activation, Rheology, Recycled concrete powder, Setting time, Rheology, Compressive strength
|
