Abstract
Bauxite refinery residue (BRR), a byproduct of alumina production, has significant potential for applications in the construction industry due to its favourable chemical composition and abundant availability. However, its use as a supplementary cementitious material (SCM) is limited by its low pozzolanic reactivity. This study investigates the pozzolanic reactivity of BRR through both indirect and direct methods. BRR was used to replace Ordinary Portland Cement (OPC) at 5%, 10%, 15%, 20%, 25%, and 30% by weight. Mortar compressive strength was tested at 3, 7, and 28 days, while pozzolanic reactivity was directly assessed using the modified Chapelle test. BRR characterisation included the analysis of chemical composition and particle size distribution, and amorphous content. Results show that raw BRR contributes significantly to early strength development, with all replacement levels (5–30%) exhibiting higher 3-day compressive strength than the plain cement mortar (13.21 MPa). The strength peaked at 16.92 MPa with 5% BRR replacement and remained relatively high across the full replacement range, from 15.0 to 16.92 MPa. In contrast, 28-day compressive strength showed a declining trend with increasing BRR content beyond 10%, indicating limited long-term pozzolanic activity. To address this, BRR was subjected to calcination at 600 °C, 650 °C, and 700 °C. Among these, the BRR calcined at 650 °C showed the improvement in pozzolanic reactivity compared to raw BRR.
Keywords
bauxite refinery residue, supplementary cementitious material, pozzolanic reactivity, modified Chapelle test, compressive strength.
DOI
10.5703/1288284318127
Recommended Citation
Siwakoti, Pukar; Nepal, Jaya Acharya; Barbhuiya, Salim; and Ayati, Bamdad, "Enhancing the Pozzolanic Reactivity of Bauxite Refinery Residue for Cementitious Applications through Calcination Treatment" (2025). International Conference on Durability of Concrete Structures. 2.
https://docs.lib.purdue.edu/icdcs/2025/sce/2
Enhancing the Pozzolanic Reactivity of Bauxite Refinery Residue for Cementitious Applications through Calcination Treatment
Bauxite refinery residue (BRR), a byproduct of alumina production, has significant potential for applications in the construction industry due to its favourable chemical composition and abundant availability. However, its use as a supplementary cementitious material (SCM) is limited by its low pozzolanic reactivity. This study investigates the pozzolanic reactivity of BRR through both indirect and direct methods. BRR was used to replace Ordinary Portland Cement (OPC) at 5%, 10%, 15%, 20%, 25%, and 30% by weight. Mortar compressive strength was tested at 3, 7, and 28 days, while pozzolanic reactivity was directly assessed using the modified Chapelle test. BRR characterisation included the analysis of chemical composition and particle size distribution, and amorphous content. Results show that raw BRR contributes significantly to early strength development, with all replacement levels (5–30%) exhibiting higher 3-day compressive strength than the plain cement mortar (13.21 MPa). The strength peaked at 16.92 MPa with 5% BRR replacement and remained relatively high across the full replacement range, from 15.0 to 16.92 MPa. In contrast, 28-day compressive strength showed a declining trend with increasing BRR content beyond 10%, indicating limited long-term pozzolanic activity. To address this, BRR was subjected to calcination at 600 °C, 650 °C, and 700 °C. Among these, the BRR calcined at 650 °C showed the improvement in pozzolanic reactivity compared to raw BRR.
