TY - JOUR
T1 - Effects of key factors on the compressive strength of metakaolin and limestone powder-based alkali-activated concrete mixtures
T2 - An experimental and statistical study
AU - Ahmad, Shamsad
AU - Bahraq, Ashraf A.
AU - Shaqraa, Abbas Albu
AU - Khalid, Hammad R.
AU - Al-Gadhib, Ali H.
AU - Maslehuddin, Mohammed
PY - 2022/6/1
Y1 - 2022/6/1
N2 - The present study aimed at utilizing locally available metakaolin (MK) and limestone powder (LSP) as base binders for developing alkali-activated concrete. Ordinary Portland cement (OPC) was used as a secondary binder. Specimens with different primary binder (MK or LSP), its content (70%, 85%, or 100%), activator type (NaOH- or KOH-based), and activator composition (sodium silicate/hydroxide ratio: 1, 2.5, or 4) were prepared, and tested for compressive strength. The obtained strength data were statistically analyzed using ANOVA and response surface methods (RSM) to explore the effects of the studied variables. Test results showed that all the considered parameters had significant effects on the tested properties where the effect of the primary binder content was more pronounced than the alkaline composition. Two mixtures (70% MK with sodium silicate/KOH ratio of 2.5 and 70% LSP with sodium silicate/KOH ratio of 4.0) showed more than 20 MPa strength, which can be categorized as structural concrete. While all the remaining mixtures exhibited less than 20 MPa strength. These can find non-structural applications such as backfill, footpath slab, or controlled low strength materials (CLSM).
AB - The present study aimed at utilizing locally available metakaolin (MK) and limestone powder (LSP) as base binders for developing alkali-activated concrete. Ordinary Portland cement (OPC) was used as a secondary binder. Specimens with different primary binder (MK or LSP), its content (70%, 85%, or 100%), activator type (NaOH- or KOH-based), and activator composition (sodium silicate/hydroxide ratio: 1, 2.5, or 4) were prepared, and tested for compressive strength. The obtained strength data were statistically analyzed using ANOVA and response surface methods (RSM) to explore the effects of the studied variables. Test results showed that all the considered parameters had significant effects on the tested properties where the effect of the primary binder content was more pronounced than the alkaline composition. Two mixtures (70% MK with sodium silicate/KOH ratio of 2.5 and 70% LSP with sodium silicate/KOH ratio of 4.0) showed more than 20 MPa strength, which can be categorized as structural concrete. While all the remaining mixtures exhibited less than 20 MPa strength. These can find non-structural applications such as backfill, footpath slab, or controlled low strength materials (CLSM).
KW - Alkali-activated binders
KW - Limestone powder
KW - Metakaolin
KW - Optimization
KW - Response surface method
UR - https://www.scopus.com/pages/publications/85123420550
U2 - 10.1016/j.cscm.2022.e00915
DO - 10.1016/j.cscm.2022.e00915
M3 - Article
AN - SCOPUS:85123420550
SN - 2214-5095
VL - 16
JO - Case Studies in Construction Materials
JF - Case Studies in Construction Materials
M1 - e00915
ER -