Application and Texture of Ground RC as Supplementary Cementitious Material

Abstract

This paper investigates the application of milled recycled concrete aggregates (RC) as supplementary cementitious material (SCM). To enhance usage of fine RC aggregates 6 different source materials of type 1 as per DIN 4226-101 were investigated for its potential application as SCM. The RC aggregates have been partly organized by recycling companies and partly prepared in the laboratory. The RC aggregates were processed by a ball mill to produce SCM. The particle distribution was investigated with a laser diffraction device. Together with a Portland cement the SCMs were mixed in different dosages (10, 20 and 30 wt% cement replacement), a limestone filler (L) served as reference. Mortar prisms were made and tested according to EN 196-1. In terms of strength performance the SCM types showed a decrease with increasing dosage indicating only an inert filling effect. Interestingly, the SCMs with higher loss of ignition (LOI) performed better than the SCMs made in laboratory out of old concrete samples. The particle density distribution of the SCM were qualitatively comparable – however differences in specific diameters of 15 - 20% occurred. The finer SCM types showed a better performance.