Role of industrial by-products and metakaolin in the development of sustainable geopolymer blends: Upscaling from laboratory-scale to pilot-scale

In this experimental work, the geopolymer blends were synthesized from metakaolin, fly ash, and sugarcane bagasse ash based on their low cost and easy availability to improve the strength and durability of the newly developed product. In this research, a multilevel investigation has been carried out in two phases i.e., initially at the laboratory-scale which was then upscaled to pilotscale. In the laboratory-scale study, the precursors namely, metakaolin, fly ash, and sugarcane bagasse ash were used in the multilevel materials investigation i.e., these materials were tested at mono level, binary level, and ternary level. Cylindrical specimens with 500 mm diameter and 100 mm height in size were cast by applying a constant pressure of 10-MPa. The samples were prepared with 10 M solution of NaOH and a Na2SiO3/NaOH ratio of 1.5 and were cured under normal room temperature. Upscaling of the optimized mixes, as revealed from the laboratoryscale investigation, was carried out at the pilot-scale by simulating the laboratory conditions for casting the full-sized brick specimens. The mechanical properties and durability aspects of the upscaled-brick specimens were investigated and compared with the standard codes of practice for conventional burnt clay bricks, leading to satisfactory results overall. The strength and durability of the developed product were enhanced due to the formation of the sodium- and calcium-based aluminosilicate hydrates i.e., N-A-S-H and C-A-S-H, which were validated through FTIR and SEM analysis. Interestingly, multilevel investigation of the blends helped in identification of the geopolymerization potential of these materials at different levels (mono, binary, and ternary level in this study).

Automated summary

In this experimental work, geopolymer blends were synthesized using low-cost materials to improve the strength and durability of the developed product. A multilevel investigation was conducted at both laboratory-scale and pilot-scale, and the results showed satisfactory mechanical properties and durability of the upscaled-brick specimens. The formation of sodium- and calcium-based aluminosilicate hydrates contributed to the enhanced strength and durability. Multilevel investigation helped identify the geopolymerization potential of the materials at different levels.