Influence of Aggregate on Properties of Semi-dry Concrete in Hardened State

The article deals with the influence of various aggregate compositions used to semi-dry concrete on some properties of hardened concrete. The concrete mix compositions were aimed at using in precast production of manholes and pipes for sewerage systems. Five fractions of aggregate (0/1, 0/2, 0/4, 2/4 and 4/8, respectively) were used, while grains of fraction 0/1 had rounded shape and fractions 0/2 and 0/4 were pre-crushed. Fraction 2/4 and 4/8 included half of rounded as well as half of crushed grains. Concrete mix compositions also varied within the content of cement paste according to experiences from production plant. The concrete surface (from -2 to 1), density of hardened concrete in saturated and dried state (from 2265 to 2416 and from 2142 to 2336 kg.m-3), splitting strength (from 4.9 to 6.2 MPa) and water absorption (from 3.4 to 5.8 wt%) were observed.