Research on Enhancing the Corrosion Resistance of Concrete in a MgSO4 Corrosive Environment Using CTF Synergist

Abstract

Concrete structure is easy to be damaged by corrosion in natural environment. In order to find a new way to improve the corrosion resistance of concrete. In this paper, the effect of Coal Tar Fuel (CTF) synergist on the corrosion resistance of concrete was analyzed by using MgSO4 solution with concentration of 5% as corrosion medium. The change rule of concrete pore structure was studied. And the performance of concrete interfacial transition zone (ITZ) is studied. Finally, the effect of CTF synergist on hydration reaction of cementitious materials was revealed. The results show that the addition of 0.7% CTF synergist can significantly enhance the corrosion resistance of concrete, even with 10% reduction in cement dosage. After 28 days of being cured under this dosage, there is 13.54% increase in the proportion of pores with a diameter less than 100 µm and a 5.36% decrease in the proportion of pores with a diameter greater than 600 µm. Meanwhile, the microhardness of ITZ increases by 41.14%, while the width of ITZ decreases by 12.5%. Additionally, there is a reduction in the maximum crack width at the interface between ITZ and aggregate by 1.8 µm. The exothermic reaction of the cementitious material during hydration is more pronounced when the hydration time exceeds one hour.