Investigation of effect of zeolitic tuff addition on concrete properties and corrosion of reinforced concrete steel

In this study, effect of zeolitic tuff (ZT) addition on concrete properties and corosion of reinforced concrete steel were investigated. The usability of zeolitic tuff sample that was obtained from rocks belonging to Balikesir Bigadiç region as pozzolan was investigated. ZT was replaced with Portland cement (CEM I) in ratio of % 0, % 10, % 20, % 30 and % 40 by weight and different of samples were prepared with tap water and cured in tap water and in sea water. Standard consistency, setting time, volume expansion of cements pastes; compressive and flexural strength of cement mortar were investigated. The 40x40x160 mm mortar prism specimens for mortar tests; 100×200 mm concrete cylinder specimens for concrete compressive strenght and accelerated chloride ion penetration; 200×200×120 mm concrete prism specimens for depth of penetration water and ultrasonic pulse velocity; 50×100 mm specimens of cylinder reinforced concrete for corrosion measurement were prepared. The corrosion of reinforcement on the reinforced concrete added ZT specimens was investigated by different electrochemical measurement methods. The reinforced concrete bar for determination parameter of electrochemical corrosion used three electrode method. After the corrosion tests, the steel-concrete interface and concrete micro structure using scanning electron microscope (SEM) was investigated. Concrete compressive strenght value of 360 days of concrete with ZT addition in ratio of %10, %20, %30, %40 were higher %18,3, %14,0, %8,8 ve %5,3 than control samples was observed. ZT addition with high silica composition provide by pozzolonic effect thanks to reactions of cement gel carry and porosity decrease of concrete. As the ZT addition increased, polarisation resistance of reinforced concrete increased and corrosion current decreased. The risk of localized corrosion was decreased by the layer of ZT that was blocked ion transition on the reinforced concrete steel surface. Consequently the reinforced concrete steel was protected well than localized corrosion by concrete with ZT addition in ratio of %30 especially in the effect of splash sea water environment.