Simulation of internal damage in water-saturated cement paste by frost action

Author(s): L. Liu, H. S. Chen, W. Sun
Paper category: Proceedings
Book title: Proceedings of the Seventh International Conference on Concrete under Severe Conditions – Environment and Loading
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 305-312
Total Pages: 8
Language : English

Abstract: Frost damage of concrete is an important issue with regard to the durability and service life prediction of concrete structures in cold climates. According to the thermodynamics of ice growth and fracturing of hydrated cement paste, the internal damage of water-saturated cement paste is quantified by numerical simulation in this paper. Based on a microstructure of cement paste from a HYMOSTRUC3D model, its pore structure is extracted and characterized as a series of pore clusters with various sizes. As temperature decreases, crystals of ice propagate in the pore clusters. Under the condition of heterogeneous nucleation at a temperature lower than zero and a fast temperature decreasing scheme, hydraulic pressure is generated because of a significant expulsion of unfrozen water from the freezing sites. Assuming hydraulic pressure as the main damage source of stress during the freezing process, the internal fracturing of cement paste is obtained by use of three-dimensional (3D) lattice fracturing model. For cement paste with 0.4 water-to-cement ratio and 0.69 degree of hydration, the creation of micro-cracks in its microstructure with a size of 50 μm × 50 μm × 50 μm is illustrated. Simulations show that the lower the nucleation temperature is, the more serious the internal damage is caused.At low ice crystal saturation degree, the created micro-cracks are randomly distributed in the microstructure of cement paste. While at high ice crystal saturation degrees, the propagation of micro-cracks occurs and a continuous crack is formed.

Online publication : 2013
Publication type : full_text
Public price (Euros) : 0.00