Taguchi-optimized triple-aluminosilicate geopolymer bricks with recycled sand: A sustainable construction solution

Rapid infrastructure development has led to an enormous demand for cement and a huge production of construction and demolition (C&D) waste. The ever-growing demand for cement is leading to a very high amount of CO2 emissions in the atmosphere. This research article focuses on addressing these two major issues of CO2 emission and inadequate handling of C&D waste by developing novel geopolymer bricks by utilizing the three-aluminosilicate waste materials, which includes rice husk ash (RHA), ground granulated blast furnace slag (GGBS), and red mud, and using recycled washed sand as filler. Taguchi's method was used to develop the geopolymer mix design by making use of four factors, i.e., binder percentage with six levels and three levels for alkaline solutions, sodium silicate/sodium hydroxide (SS/SH), and alkaline to binder ratio(A/B). A novel approach is adopted for preparing the alkaline solution using three different techniques which are highlighted in this research study. The compressive strength and water absorption were tested, and the optimum percentage of mix was found with B5 binder, which includes 60 % RHA, 20 % GGBS, and 20 % red mud with an alkaline solution of A2, SS/SH as 2, and alkaline/binder as 0.45. The maximum compressive strength found to be 27.34 MPa, and the minimum water ab-sorption was also recorded at this combination, which was 5.68 %. The compressive strength and water absorption were negatively correlated with a degree of 96 % found by using the parametric map. Desirability analysis and statistical analysis using ANNOVA techniques were used to discover the optimum percentage. Microscopic analysis was performed on the highest and lowest values of the L18 design of the experiment by Taguchi's method. Along with this, a clustering algorithm was used to evaluate the scanning electron microscope (SEM) images. The overall research study suggested that the percentage of binder and alkaline solution were the governing factors for the properties of geopolymer bricks.