Investigation of Influence of Rice Husk Ash and Corn Cob Ash as Mineral Concrete Admixtures on Chloride Migration Using Electrochemical Technique

The EIS method was used in the current study to investigate the chloride ion migration depth of Portland cement blended with rice husk ash (RHA) or corn cob ash (CCA), which was based on quantitative analyses of EIS data and electrochemical parameters of the equivalent circuit model to describe the ingress of chloride ions into cementitious media and determination of migration depth. The SEM and compressive strength analyses were also used to investigate the depth of chloride migration in the blended cement. The results of EIS analyses showed that increasing the content of RHA and CCA decreased chloride ion migration in cementitious media, and based on the findings, EIS analyses could predict the depth of chloride ion penetration in cementitious environments with different mineral admixture replacements. Furthermore, adding 10% RHA and 30% CCA to concrete cement (RHA10+CCA30) improves resistance to chloride ion migration and corrosion while also increasing the compressive strength of concrete after four weeks of curing time. Because the synergetic effect of RHA and CCA in RHA10+CCA30 can fill in the gaps between cement particles and aggregates, SEM analyses of steel rebar incorporated into the RHA10+CCA30 sample revealed lower pitting corrosion and corrosion products compared to the control sample (PC0).