Effects of nano palm oil fuel ash on hydration of cement under the accelerated carbonation curing

•Accelerated carbonation reaction of cement paste due to the nPOFA.•Conversion of CSH to Ca-modified silica gel and poorly crystalline CaCO3.•The synergetic effects of carbonation curing and usage of nPOFA for carbon sequestration. The ultimate goal of usage of supplementary cementitious materials and accelerated carbonation curing in concrete is to reduce the generation of CO2. This study firstly investigated the effect of nano Palm Oil Fuel Ash (nPOFA) on the accelerated carbonation curing of cement paste. The results showed that P30 (30% of nPOFA) had larger amounts of Ca-modified silica gel from the decalcification of CSH and calcium carbonate compared to P0 (0% of nPOFA). It might be assumed that high contents of potassium oxide in nPOFA accelerates the ionization of CO2 and carbonation of calcium silicates and hydration products.