This thesis deals with the properties of fresh and hardened highly flowable concrete of various
compositions with the same water-binder ratio. We examined four different concrete mixtures
which differed by the type of aggregate and/or binder. All concrete mixtures were prepared
with a polycarboxylate superplasticizer. We studied the influence of two types of crushed
carbonate aggregate, i.e. Portland cement CEM I and mineral additive fly ash, with witch we
replaced 20 % of the Portland cement in the binder.
In the first part of the study we tested the influences of the type of aggregates and mineral
additive through rheological properties of fresh concrete mixtures in the period of one hour
after mixing. Using slump test and flow table test we estimated the consistency of fresh
concrete. We used porosimeter to determine the amount of air bubbles in concrete and
rheometer to measure yield stress value and plastic viscosity of the concrete mixtures.
In the second part of the study we determined mechanical properties. Using samples of
hardened concrete, we evaluated its compressive strength, modulus of elasticity and resistance
to penetration of water after 3, 28 and 90 days. The results of the study were used to compare
the above mentioned properties and to evaluate the influences of various types of aggregates
and mineral additive on the properties of fresh and hardened concrete.