APPLICATION OF A PORE-SCALE REACTIVE TRANSPORT MODEL TO STUDY THE INFLUENCE OF PORE NETWORK CHARACTERISTICS ON CALCIUM LEACHING IN CEMENTITIOUS SYSTEMS

Author(s): Ravi A. Patel, Janez Perko, Diederik Jacques, Geert De Schutter, Guang Ye and Klaas Van Breugel
Book Title: RILEM International Symposium on Concrete Modelling - CONMOD 2014
Editor: Kefei Li, Peiyu Yan and Rongwei Yang
ISBN: 978-2-35158-139-1
e-ISBN: 978-2-35158-140-7
Publisher: RILEM Publications SARL
Publication year: 2015
Pages: 359-366
Total Pages: 8
Language: English

Abstract: Calcium leaching in cement paste causes dissolution of portlandite and AFm phases which results in the opening of capillary pores and decalcification of amorphous C-S-H resulting in an increase of gel porosity. These alterations in turn affect transport and mechanical properties of cement paste. The aim of this study is to analyse the influence of microstructure on leaching behaviour. A lattice Boltzmann based pore scale reactive transport model is used with a reactive term computed using a simplified reaction model for portlandite system. This simplified reaction model is pre-computed using full geochemical model. This approach is computationally more efficient and was found to be reasonably accurate for porescale simulation when compared to full geochemical model. To explore the role of pore network characteristics on transport properties and the calcium leaching front, the developed approach was applied to a series of simulations on randomly simulated pore structure. In particular the influence of particle shape, particle size, porosity and tortuosity was investigated. It was found that the parameters governing transport of species such as porosity and tortuosity have a more dominant effect on leaching compared to parameters related to the particle shape and size such as surface area. These results also lead to the important conclusion that transport of species at the pore scale model is essential to capture correct behaviour.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00