Effect of bottom ash powder replacement rate, water cement ratio and sand cement ratio on alkali activated slag mortar

The main objective of this study is to clarify the effect of bottom ash (BA) powder replacement rate, water-cement ratio, and sand-cement ratio on alkali-activated slag mortar (AASM) by comprehensively investigating the following parameters: fluidity, consistency, setting time, pH, compressive strength, and flexural strength, as well as observing the microstructure by XRD and SEM. Finally, the relationship between the parameters was explored by means of correlation coefficient heatmaps in concert with scatter plots (including quadratic polynomial linear fitting). The results show that it is feasible to use up to 60% of BA powder to replace slag for AASM. Meanwhile, it is suggested that the AASM with a water-cement ratio of 0.44 and a sand-cement ratio of 2.6 can obtain better workability, mechanical properties, and a denser microstructure. The incorporation of BA powder produces the unique hydration product Magadiite. In addition, the mechanical models of compressive strength and flexural strength of AASM were proposed . This study provides a reference for the application of BA powder in the alkali-activated system, which is beneficial for resource recycling.