Chloride-binding capacity of ternary concretes containing fly ash and untreated sugarcane bagasse ash

In order to understand the role of untreated sugarcane bagasse ash (UtSCBA) in chloride binding of ternary concretes prepared with fly ash, an experimental program was carried out. Concrete specimens containing only Portland cement, Portland cement + fly ash and Portland cement + fly ash + UtSCBA were manufactured. After curing these specimens were exposed to a chloride solution for 3000 days. After exposure, a microstructural characterization using scanning electron microscopy and X-Ray diffraction was conducted. The compressive strength, electrical resistivity of the concretes and percentage of voids, were also obtained, while information on chloride binding was obtained from the difference between the amount of total and free chlorides. Diffractograms showed that chlorides chemically reacted with the Afm and Aft phases of all concretes to form Friedel's salt. In summary, ternary concretes containing UtSCBA showed the highest chloride-binding capacity.

Automated summary

The experimental program revealed that ternary concretes containing untreated sugarcane bagasse ash (UtSCBA) exhibit the highest chloride-binding capacity. Chemical reactions between chlorides and the Afm and Aft phases in all concretes were observed, forming Friedel's salt.