Microstructure evolution of leached cement paste: Simulation and experiments: Fid-Bau Portal

Microstructure evolution of leached cement paste: Simulation and experiments

Chen, Bofu / Tian, Bin / Lu, Xiaochun / Xiong, Bobo

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Highlights • A reactive transport model is developed to simulate changes in microstructure of leached cementitious composites. • The transport properties of each pore size were quantified to predict the pore size evolution of each pore. • The model is successfully applied to predict the pore size distribution of leached cementitious composites. • The connected pores caused by the increasing threshold pore size accelerate the growth of threshold pore size.

Abstract In this paper, a reactive transport model is developed to simulate changes in the microstructure of leached cementitious composites. The model simultaneously takes into account the relation between the real microscopic pore size and macroscopic porosity via MIP and nitrogen adsorption, and the coupling between pore size and the transport properties. Quantitative validation of the model is achieved by comparison of simulation and leaching experiments, and the results show good agreement in terms of both the microscopic pore size distribution and the macroscopic porosity. In addition, SEM analysis and simulations indicates that decalcification may leads to a connection of the adjacent pores, and the increase in the critical pore size is much smaller than the threshold pore size. Some adjacent pores may be connected due to the growing threshold pore size, and the new connected pores will accelerate the growth of the threshold pore size. Besides, leaching induces additional peak on differential pore size distribution curve.