CONCRETE'S SELF-HEALING POTENTIALS FOR PROMOTING DURABILITY; NUMERICAL EVALUATION OF CONTRIBUTIONS FROM UNHYDRATED CEMENT

Transport of harmful substances through the pore space of concrete can give rise to deterioration of concrete structure or to corrosion of steel reinforcement. Internal and external influences, e.g. shrinkage and freeze-thawing, will additionally lead to the fort-nation of myriads of tiny cracks in the virgin state. These cracks can have detrimental impact on concrete durability. Cement particle nuclei left unhydrated in concrete after complete maturation can provide under favorable conditions self-healing capability to micro-cracked concrete. Basically, the self-healing capability can be expected depending on the amount of unhydrated cement, however, also on the number and spacing of the nuclei of unhydrated particles. This is obviously a configuration-sensitive material problem for which common RSA-based computer simulation systems cannot provide reliable estimates. Therefore, the concurrent algorithm-based computer simulation system with the acronym SPACE has been employed. The impact of principal design parameters of concrete (cement fineness, water to cement ratio) on maximum healable micro-crack opening is emphasized.