Investigation of the effect of commercial limestone on alkali-activated blends based on Algerian slag-glass powder

We have investigated the potential use of commercial limestone powder (LP) of 10 to 40%.wt to replace slag in a new ternary alkaline system (BFS-GP-LP) activated by both (Na2SiO3 and NaOH). Ten mixtures of AAPs and AAMs are prepared; the aim is to understand the influence of precursor on fresh property, reaction kinetics and products, mechanical and microstructural properties; then it's compared with those of OPC. The findings indicate that the setting times of AAPs are prolonged when increasing LP content to by 40% (870, 1042 min); however, they are slower compared to OPC (320, 425 min). Despite the incorporation of LP improves spreading values to 184 mm, AAMs registered less workability than OPC. Using 20% GP provides a better CS (68 MPa) and FS (10 MPa); using LP harms strengths, but its use by 10%.wt improves the early age FS of MSG from 3.67 to 5.25 MPa and provides a higher CS (62.90 MPa) than OPC (60.90 MPa). The formation of reaction products is prolonged to 162 h when using 40% LP. Characterization testing identified that the main reaction product of AAMs is C-S-H gel. Microstructural analysis indicates that the samples contain LP have a heterogeneous and less compact structure.

Automated summary

This study investigates the use of commercial limestone powder in a new ternary alkaline system, and the results show that increasing LP content prolongs setting times but with slower rates compared to OPC; samples containing LP have a less compact structure.