Properties of cement screeds using recycled fine aggregates with respect to cement percentage

Abstract

This article deals with the effect of 100% replacement of natural aggregate by recycled aggregate and at the same time the effect of cement percentage on the observed properties of cement screeds. For these purposes, concrete and brick recycled aggregate is used in combination with CEM I 42.5R Portland cement, constituting 10 %, 15 %, 20 % and 25 % of the mixtures weight. To determine the properties of the cement screeds, test intervals of 3, 7, 14, 21 and 28 days are set, during which changes in bulk density are monitored. Simultaneously, destructive tests are carried out on test beams of 4 × 4 × 16 cm in size. The results found that the use of recycled fine aggregates allows the production of lighter cement screeds, for example, for reconstruction. Potentially usable mixes appear to be those containing 15 %, 20 % and 25 % cement compared to recycled aggregate. For the contaminated recyclate fine fraction, the flexural strength has been shown to improve. However, this improvement is not reflected in an increase in compressive strength.