Corrosion resistance of ultra-high performance fibre- reinforced concrete

Abstract

The corrosion resistance of ultra-high performance concrete (UH) made with different fibre contents and under distinct curing conditions was studied. No signs of carbonation were observed after 1 year of accelerated carbonation testing (3% CO2). The fibreless UHs’ electrical resistivity was above 5000 Ω·m, although these values were 2-fold higher than a UH with 1% fibres and approximately 5-fold higher than a UH with 2% fibres. Concrete resistance to chloride penetration was also extremely high (the diffusion coefficient equalled 1.3·10−13 m2/s) and curing temperatures of 60 °C or 90 °C improved even more these properties, while lack of curing made them slightly worse. Given these excellent properties, the corrosion rate in specimens submerged in chloride solution for 1 year was negligible (iCORR from 0.007 to 0.025 µA/cm2). These values remained stable with time, unlike the 50 MPa concrete at 2 months when iCORR starting to increase and was 12-fold higher after 1 year. The time estimated for corrosion onset in UH is on average about 150-fold higher than that of 50 MPa.