Corrosion resistance of cement-based materials with sugarcane bagasse ash-metakaolin-Portland cement binder under carbonic acid water environment

Abstract

This paper investigated the corrosion process of sugarcane bagasse ash (SCBA)-metakaolin (MK)-Portland cement (PC) system under carbonic acid water environment. The phases of cement paste before and after corrosion and microstructure were analyzed by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscope. The results showed that the addition of SCBA to mortar does not significantly enhance overall strength or reduce corrosion depth, whereas MK exhibits superior strength (up to 13.1% higher than SCBA) and lower corrosion depth (up to 69.6% lower than SCBA after 90 days of corrosion). Furthermore, SCBA is more conducive to maintaining strength over time compared with MK. When both MK and SCBA are used in mortar, particularly with a MK content exceeding 15% and an SCBA content below 5%, the optimal corrosion resistance effectiveness can be achieved. This is attributed to the synergistic pozzolanic effect of MK and the filling effect of SCBA.