Investigation of the effect of commercial limestone on alkali-activated blends based on Algerian slag-glass powder
Hichem Alioui, Tarek Chiker, Fatma Saidat, Mohamed Lamara, Salima Aggoun, Oualid Mahieddine Hamdi
Abstract
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.