Influence of composition on the corrosion of steel bar of reinforced geopolymer concrete

The three key oxide molar ratios of geopolymer concrete: n(SiO2)/n(Al2O3), n(Na2O)/n(Al2O3) and n(H2O)/n(Na2O) were studied in this paper to determine their effects on reinforced geopolymer concrete by testing the corrosion weightless rates of reinforcing steel bar and carbonation depth. It was found that both of them were decreased first but increased at a certain point with increasing n(SiO2)/n(Al2O3); they showed a downtrend with the increase of n(Na2O)/n(Al2O3). Increasing n(H2O)/n(Na2O) caused an increase in both of them while a small decline was observed in carbonation depth when n(H2O)/n(Na2O)<28. With the the same amount of cementitious material, resistance to corrosion of steel bar of geopolymer concrete was better than that of common concrete.