| Title |
A Model for Predicting the Autogenous Shrinkage of High-strength Concrete |
| Keywords |
High-strength Concrete ; Autogenous Shrinkage ; Hydration Ratio ; Pore-Size Distribution |
| Abstract |
Autogenous shrinkage of concrete has been defined as decrease in volume due to hydration. For ordinary concretes, autogenous shrinkage is so little that it has been dignored. It has recently been reported, however, that cracking can be caused by autogenous shrinkage, when high- strength concretes were used.??In this study, we propose an analytical system to represent autogenous shrinkage in cement paste and concrete in order to control crack due to autogenous shrinkage. The system composed of the hydration model and pore structure model. The hydration model which refined Tomosawa's represents the situation that inner and outer products are made in cement paste.??The pore structure model is based upon the physical phenomenon of ion diffusion in cement paste. The proposed model can predict the pore volume ratio and the pore structure in cement paste under variable enviromental conditions satisfactorily. The fomula for elastic modulus change of cement paste according to hydration was made in order to calculate autogenous shrinkage. The model for predicting autogenous shrinkage of cement paste and high-strength concrete shows a reasonable agreement with the experimental data of various mix-proportions. |