Effects of pozzolanic treatment method of aggregate on recycled aggregate high strength concrete properties

The construction industry is now confronted with two major challenges: the depletion of natural resources and the increase in trash from building and demolition projects. Reusing and recycling building and demolition waste is one approach that addresses both problems simultaneously. The effects of pre-mixing treated coarse aggregate (RA) and natural aggregate (NA) on the characteristics of high-strength concrete (HSC) are examined in this research. Moreover, studying HSC performance based on different replacement ratios of coarse RA from coarse NA. Nine HSC mixtures were prepared in this study with various parameters. The first parameter includes three replacement ratios of coarse RA that were 0 %, 50 %, and 100 %. The second parameter is the treatment method of the coarse NA and RA. Three treatment methods were conducted in this investigation on each RA replacement ratio which were water, rice husk ash (RHA) slurry, and sugar bagasse ash (SBA) slurry. The concrete waste has been collected, crushed, sieved, and treated using methods stated previously before adding to other concrete components. The HSC mixes were tested freshly, mechanically, and physically. Slump test and air content are measured at the fresh state. To ascertain the mechanical characteristics of HSC, tests are conducted on the hardened state to measure compressive, indirect tensile, flexural, and modulus of elasticity strengths. Permeability to chloride ions, sorptivity to water, and water permeability are among of the physical characteristics of HSC mixtures discussed in this study. The microstructure of HSC mixes was analyzed using scanning electron microscope (SEM), and energy dispersive x-ray (EDX) of RHA and SBA also analyzed. The RHA slurry treatment exhibits a lower reduction in the slump value than SBA slurry treatment method. SBA slurry treatment is a better treatment method than water and RHA slurry treatments especially with mix 50 %NA and 50 %RA. The treatment of coarse aggregate using RHA and SBA slurries can enhance the concrete mix to resist the chloride penetration, water sorptivity, and permeability.