A polydispersed particle system representation of the porosity for non-saturated cementitious materials

• Published in: Cement and concrete research Vol. 36; no. 11; pp. 2061 - 2073
• Main Author: Bary, B.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Ltd 01.11.2006; Elsevier Science; Elsevier
• Subjects: Applied sciences; Buildings. Public works; Cement concrete constituents; Cements; Concretes. Mortars. Grouts; Exact sciences and technology; General (composition, classification, performance, standards, patents, etc.); Materials; Modeling; Nuclear Experiment; Nuclear Theory; Numerical simulation; Physical properties; Physics; Polydispersed particle system; Pore size distribution; Properties and test methods; Properties of anhydrous and hydrated cement, test methods; Numerical simulation; Pore size distribution; Modeling; Physical properties; Polydispersed particle system; Composite material; Pore size; Adsorption; Cement; Isotherm; Capillary pressure; Polydispersed particle; Porosity; Pore Size Distribution; Polydispersed Particle System; Numerical Simulation; Physical Properties
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2006.07.001

In this paper, the porosity of cementitious materials is described in terms of pore size distribution by means of a 3-dimensional overlapping sphere system with polydispersivity in size. On the basis of results established by Lu and Torquato [B. Lu, S. Torquato, Nearest-surface distribution functions for polydispersed particle systems, Phys. Rev. A 45(8) (1992) 5530–5544] and Torquato [S. Torquato, Random Heterogeneous Media: Microstructure and Macroscopic Properties. Springer-Verlag: New York, 2001] providing relations for nearest-neighbor distribution functions, the volume fraction of pores having a radius larger than a prescribed value is explicitly expressed. By adopting an appropriate size distribution function for the sphere system, it is shown that the pore size distribution of cementitious materials as detected for instance by mercury intrusion porosimetry (MIP), which generally points out several pore classes, can be well approached. On the basis of this porosity representation, the evaluation of the capillary pressure in function of the saturation degree is provided. The model is then applied to the simulation of the saturation degree versus relative humidity adsorption curves. The impact of the pore size distribution, the temperature and the thickness of the adsorbed water layer on these parameters are assessed and analyzed for three model materials having different pore characteristics.