| Abstract [eng] |
The aim of thesis is to evaluate crystalline admixtures influence to concrete and its products. Results of tests show that usage of the crystalline admixtures does not determine temperature, density and air content of concrete mixtures, but different consist of admixtures and concentration can change the slump of mixed concrete. Also, crystalline admixtures decrease concrete`s early strength comparing with control tests and reach about 85% after 1 day of curing. But after 7 and 28 days of consolidation these specimens became stronger. The impact of frost for concrete products was examined with hydration kinetics test. Results of this test shows that specimens with crystalline additives have less resistance to frost than control specimen. But the resistance is changed after 1-3 months of curing. Specimens with crystalline additives reach not lower theoretically calculated resistance to frost than control specimen. It is important to notice that damaged specimens of self- healing concrete recover from frost resistance faster after curing than control specimen. Results of freezing slab test do not show any significant differences, but freezing cube test shows that specimens with crystalline additives are more resistance than control specimen. The last test related to frost impact was capillary suction test which shows that crystalline admixture determines higher resistance of concrete. Other tests were done to examine carbonation depth and chloride ion ingress in concrete with different consist. The carbonation depth of specimens was measured before and after 21 days in carbonization chamber. Results show that carbonation is up to 3 mm depth in control specimen, but carbonation was completely absent in self-healing concrete specimens. Test of chloride ion ingress show that chloride ions have less influence for concrete with crystalline additives than without them. In conclusion, using crystalline admixtures for self-healing concrete has worse impact to strength and resistance to frost for early formed concrete, but they become equal after 28 days of hardening. Specimens from self-healing concrete are more resistance to effects of carbonization, chloride ion ingress and frost. |
