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Particulate structure and microstructure evolution of concrete investigated by DEM
Part 2: Porosimetry in hydrating binders

Nghi L.B. Le1, Huan He1,2, P. Stroeven1
1 Faculty of Civil Engineering and Geosciences, Delft University of Technology, the Netherlands
2 College of Architecture and Civil Engineering, Beijing University of Technology, China

Durability of concrete in engineering structures is becoming more and more of a major problem. Research into such problems is complicated and expensive, however. Developments in computer technology make it possible nowadays realistically simulating cementitious materials and studying its pore network structure. In this paper use is made of the dynamic DEM (Discrete Element Method) denoted HADES (Habanera’s Discrete Element Simulator), introduced earlier, and a new vector-based hydration simulation system, XIPKM (Extended Integrated Particle Kinetics Model). Inspired by developments in robotics, a pore exploration system is developed in DraMuTS (Double Random Multiple-Tree Structuring). The tree structure inside pores governs pore topology, including pore continuity. For determination of pore geometry such as pore size, a second uniform random point system is used. In each of these points, star volume measurements govern local pore size, while the collected data allow constructing a volume-based pore size distribution. The method is illustrated by means of data pertaining to Portland cement (PC) paste and rice husk ash-blended PC. This approach is demonstrated providing all necessary pore network information relevant for durability estimation.

Key words: Concrete, cement, DEM, hydration simulation, pore connectivity, pore size distribution, blended cement