Einfluss rezyklierter Gesteinskörnung auf das Verbundverhalten von Betonstahl in Beton.

Influence of recycled aggregate on the bond behaviour of reinforcing steel in concrete The use of recycled aggregates in common structural concretes is considered a promising approach to conserve natural resources. The present study focuses on investigating the bond behaviour of reinforcing steel in concrete with high portions of recycled aggregate from crushed concrete. To clarify a possible influence of the aggregate properties, 5 different aggregates were tested in 12 concretes. The results of the pull‐out tests were evaluated with the help of an analytical bond equation to be able to draw conclusions about the resulting design bond stress. A tendency towards a decrease in the maximum absorbable bond stress with high portions of recycled aggregate was observed. The resulting design values of the bond strength are lower than for the reference concrete, but above the specifications of Eurocode 2. The decrease in the design bond stress appears to correlate with the volume fractions of recycled aggregate and the concrete bulk density. Overall, the study shows that the bond behaviour of concrete with recycled aggregate is similar to that of normal concrete in terms of bond, shear and friction, although the actual effects also depend on the specific properties of the aggregate used. [ABSTRACT FROM AUTHOR]