Inhibition of carbonation attack in cement-based matrix due to adding graphene oxide

Abstract

Transport properties of cementitious materials are very important as they effectively influence the durability of these materials. Carbonation rate depends on the ease of carbon dioxide (CO2) movement from outer to internal surfaces. In this study, graphene oxide (GO) was incorporated in cement matrix to improve resistance of cementitious mix against carbon dioxide attack. The results showed very low carbonation depth of cementitious mix with GO (GM), only 8% of carbonation depth of the control cement mixture without GO (CM) after 6 months’ carbonation period. The most notable finding was the limited carbonation depth of GM despite the increasing of exposure to CO2. As carbonation depth increased for CM with time, full carbonation occurred after 24 months. However, GM showed no progress in carbonation front. This significant result can be attributed to interlocking influence of the CO2 molecules. Moisture loss monitoring confirms that GO sheets can act as reservoirs for water (H2O) molecules which limit transport of CO2 towards calcium phases of cement hydration. Physical interlocking was examined through molecule dynamic modelling, Monte Carlo atomistic simulation was conducted to evaluate the effects of GO sheets on carbon dioxide adsorption by cement matrix. The results showed that GO sheets reduce van der Waals adsorption energy of CO2 molecules. In addition, concentration of CO2 molecules around GO sheets was higher than the other porous areas which indicates the capability of these sheets for adsorbing of the gaseous molecule because of their high surface area.