Abstract
Computer modelling of the properties and performance of cement-based materials is complicated by the large range of relevant size scales. Processes occurring in the nanometersized pores ultimately affect the performance of these materials at the structural level of meters and larger. One approach to alleviating this complication is the development of a suite of models, consisting of individual digital-image-based structural models for the calcium silicate hydrate gel at the nanometer level, the hydrated cement paste at the micrometer level, and a mortar or concrete at the millimeter level. Computations performed at one level provide input properties to be used in simulations of performance at the next higher level. This methodology is demonstrated for the property of ionic diffusivity in saturated concrete. The more complicated problem of drying shrinkage is also addressed.
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Abbreviations
- α:
-
degree of hydration
- γ:
-
liquid surface tension
- ø:
-
porosity
- ψ:
-
stress
- σ:
-
conductivity
- c, d:
-
constants in equation to estimate mortar relative diffusivity
- D:
-
diffusivity
- H(x):
-
heaviside function = (1: x ≥0; 0 otherwise)
- P:
-
pressure
- r:
-
pore radius
- R:
-
universal gas constant
- T:
-
absolute temperature
- V:
-
volume fraction
- w/c:
-
water to cement ratio
- Agg:
-
aggregate
- 0:
-
bulk solution
- IZ:
-
interfacial zone cement paste
- m:
-
molar
- M:
-
mortar
- P:
-
bulk cement paste
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Bentz, D.P., Garboczi, E.J., Jennings, H.M. et al. Multi-Scale Digital-Image-Based Modelling of Cement-Based Materials. MRS Online Proceedings Library 370, 33–41 (1994). https://doi.org/10.1557/PROC-370-33
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DOI: https://doi.org/10.1557/PROC-370-33