Fine recycled concrete powder used as filler and cement replacement in new concrete Jaroslav TOPIČ, Zdeněk PROŠEK, Jan TREJBAL, Josef FLÁDR, Tomáš PLACHÝ Department of Mechanics, Faculty of Civil Engineering, CTU in Prague, jaroslav.topic@fsv.cvut.cz

OBJECTIVES Ecological re-use of recycled concrete powder Thermal dehydration of C-S-H gel Raw material for Portland clinker production high power demands and CO2 production Part of geopolymer binder Microfiller and partial cement replacement - high speed milling => cement grains exposure

METHODS Fresh cement paste with 50 wt. % of recycled concrete powder, w/c=0.35 Hydration heat measurement Cement pastes with 0, 33, 67 and 100 wt. % of recycled concrete powder Flexural strength test Compressive strength test Dynamic Young´s modulus - resonance method

RESULTS Hydration heat measurement Mechanical properties

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