Influence of initial hydration conditions of cement on the process and fracture parameters of hardened cement paste structure of different age

摘要

The experimentally obtained kinetic dependencies of the influence of super plasticizer on the fracture process and structural quality parameters of the compared series of the hardened cement paste samples are shown. Its analysis shows that modification of cement stone structure by superplastiticizer in quantity of 1% from cement mass at equal water - cement ratio leads, on the one hand, to the decrease of axial strength compression (R_(cs)) in the examined time intervals, on the other hand, to the sound increase of structural crack resistance, coefficient of stress intensity (K_(1C)) at the age of 420 days and 18 years which is explained by the peculiarities of hydration hardening of cement binding at the change of hardening conditions in the presence of superplasticizing additive which make possible according to X-rayogram to conclude about the influence of crystal structuring degree, value of specific surface of appearing phases and density of dislocations in the structure on the process and parameters of cement stone destruction from the position of mechanics of materials destruction.