Evaluation of surface color,compressive strength and carbonation resistance of ternary cement paste incorporating blast furnace slag and palm oil fuel ash

Abstract

Palm oil fuel ash (POFA) and blast furnace slag (BFS) have great potential as supplementary cementitious materials (SCMs) in the cement industry. In this study, the total replacement rate of POFA and BFS for cement is 60%. The color change, compressive strength development, and carbonation resistance properties were analyzed. The results show that incorporating BFS will slightly increase the brightness of the samples, and POFA will make the samples tend to be blue-black. As POFA was less reactive than BFS during testing. The 60P and 60S correspond to the lowest and highest mechanical performance and carbonation resistance performance respectively. In addition, the calcium carbonate content of samples at different depths was characterized by using FTIR, chemical composition analysis method, and compared carbonation depth by phenolphthalein method. It is found that the results obtained by the three methods are close, and due to the difference between the reaction rate and diffusion rate of CO2, The CaCO3 content on the surface of the sample is inconsistent with the change of carbonation depth. It is concluded that due to POFA has lower pozzolanic activity in early age, the properties of the samples decrease with increasing POFA content. In order to improve its utilization potential, it is feasible to use BFS and POFA to form a ternary cement system to improve performance.