Multi-response optimization of ceramic waste geopolymer concrete using BWM and TOPSISbased taguchi methods

This study examines the effect of using ceramic waste (CW) and granulated blast furnace slag (GBFS) as a blended binder on the mechanical and durability characteristics of geopolymer concrete. The experimental design was carried out following the Taguchi approach for five factors, each having four levels, to produce an L16 orthogonal array. The factors included the binder content, CW replacement by GBFS (CW:GBFS), ratio of alkaline solution to binder (AS:B), ratio of sodium silicate solution to sodium hydroxide solution (S:H), and sodium hydroxide (NaOH) solution concentration. The quality criteria were compressive strength, elastic modulus, splitting tensile strength, flexural strength, abrasion resistance, water absorption, sorptivity, ultrasonic pulse velocity, and bulk resistivity. The proportions of CW-GBFS geopolymer concrete mixes were optimized using the best-worst method and TOPSIS approach considering 9, 5, and 2 quality criteria in three scenarios. Experimental test results revealed that the optimum mix was the same for both optimization techniques irrespective of the number of quality criteria considered. The optimum mix comprised a binder content of 450 kg/m3, CW:GBFS ratio of 2:3, AS:B ratio of 1:2, S:H ratio of 3:2, and NaOH solution concentration of 10 M. The anticipated results of the optimum mix were validated through experimental testing. Its experimental test results included compressive, flexural, and splitting tensile strengths of 58.9, 5.72, and 3.81 MPa, respectively. Meanwhile, it had a water absorption of 3.45%, elastic modulus of 27.4 GPa, sorptivity of 0.025 mm/s0.5, bulk resistivity of 4652 ω•cm, abrasion resistance of 8.98%, and UPV of 6745 m/s.