Modelling the diffusivity of mortar and concrete using a three-dimensional mesostructure with several aggregate shapes

被引:163
作者
Abyaneh, S. Dehghanpoor [1 ]
Wong, H. S. [1 ]
Buenfeld, N. R. [1 ]
机构
[1] Univ London Imperial Coll Sci Technol & Med, Dept Civil & Environm Engn, Concrete Durabil Grp, London SW7 2AZ, England
关键词
Concrete; Mortar; Cement-based materials; Modelling; Diffusivity; Aggregate shape; CEMENT-BASED MATERIALS; INTERFACIAL TRANSITION ZONE; CHLORIDE DIFFUSIVITY; TRANSPORT-PROPERTIES; PERMEABILITY; PASTE; PERCOLATION; SIMULATION; MICROSTRUCTURE;
D O I
10.1016/j.commatsci.2013.05.024
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
This paper presents a numerical investigation into the effect of ITZ and aggregate shape on the diffusivity of mortar and concrete using a three-dimensional model. Concrete is treated as a three-phase composite consisting of aggregate particles, bulk cement paste and aggregate-paste interface, i.e. the 'interfacial transition zone' (ITZ). The model is set up in two stages. First, a three-dimensional representative volume element of the concrete mesostructure is generated. Then, a finite difference method is used to simulate molecular diffusion through the mesostructure. The transport properties of the conductive phases (bulk cement paste and ITZ) are determined based on the water/cement ratio, degree of hydration and porosity gradients away from aggregate particles. The model is validated against available experimental data and compared with analytical relationships for ideal cases. The model is then used to study the effect of aggregate shape on diffusivity, which has not been attempted before in three-dimensions. The model is also applied to assess the effects of water/cement ratio, degree of hydration, aggregate size, volume fraction, shape and orientation, ITZ width and percolation on diffusivity. Some of these effects are impractical to quantify from laboratory experimentation alone. It was found that the shape and orientation of aggregate particles have a significant effect on diffusivity. Diffusivity decreased when spherical aggregate particles are replaced with ellipsoidal particles due to the consequent increase in tortuosity of the cement paste. (c) 2013 Elsevier B.V. All rights reserved.
引用
收藏
页码:63 / 73
页数:11
相关论文
共 40 条
[1]  
Bentz DP, 1998, CEMENT CONCRETE AGGR, V20, P129
[2]  
BENTZ DP, 1991, ACI MATER J, V88, P518
[3]   PERCOLATION OF PHASES IN A 3-DIMENSIONAL CEMENT PASTE MICROSTRUCTURAL MODEL [J].
BENTZ, DP ;
GARBOCZI, EJ .
CEMENT AND CONCRETE RESEARCH, 1991, 21 (2-3) :325-344
[4]   Effects of cement particle size distribution on performance properties of Portland cement-based materials [J].
Bentz, DP ;
Garboczi, EJ ;
Haecker, CJ ;
Jensen, OM .
CEMENT AND CONCRETE RESEARCH, 1999, 29 (10) :1663-1671
[5]  
BENTZ DP, 1995, MATER RES SOC SYMP P, V370, P437
[6]   Influence of silica fume on diffusivity in cement-based materials I. Experimental and computer modeling studies on cement pastes [J].
Bentz, DP ;
Jensen, OM ;
Coats, AM ;
Glasser, FP .
CEMENT AND CONCRETE RESEARCH, 2000, 30 (06) :953-962
[7]   Predicting the evolution of mechanical and diffusivity properties of cement pastes and mortars for various hydration degrees - A numerical simulation investigation [J].
Bernard, Fabrice ;
Kamali-Bernard, Siham .
COMPUTATIONAL MATERIALS SCIENCE, 2012, 61 :106-115
[9]  
BUENFELD NR, 1991, MAG CONCRETE RES, V43, P135
[10]  
Crumbie A.K., 1994, THESIS IMPERIAL COLL