From Waste to Resource – Utilising Residue from Ready-Made Concrete as New Aggregate

Abstract

A new admixture is available, to reduce the sludge produced from the cleansing of production and transportation equipment in the fresh concrete industry. The result is agglomerations of hardening concrete, that might be utilised for aggregate. Utilisation depends on adequate properties. This paper reports from investigations on the physical and mechanical properties of the aggregate and discussions on the performance relative to natural and recycled aggregates and towards requirements for utilisation. The findings indicate substantial potential for utilisation, supporting the reduction of waste for deposit and development of the concrete industry towards a circular economy.

Technical and Environmental Properties of Recycled Aggregates Produced from Concrete Sludge and Excavation Materials

“…Other studies have also reported the density for recycled aggregates obtained from ready mixed concrete waste within the range 1.65-2.72% [11,16,20,26]. It can also be mentioned that Norwegian rocks typically have a density within the range of 2.65-3.10 g/mL [16]. The values obtained for density clearly show that RCZ have similar density characteristics compared to other recycled and natural aggregates.…”

“…Given the variation of WA in RCSA, it is important to consider factors such as substitution level and water-cement ratio if used in concrete. [16,23]. Overall, the results demonstrated that RCZ have better quality performance.…”

“…However, the results from acid solubility still revealed that RCZ100 contained a significant cement paste after wet treatment (see Section 3.3). Typical LA value for recycled aggregates from returned concrete waste has been reported to be 25% [16]. Generally, comparing the performance of materials investigated in this study to others e.g.…”

“…Regarding RCZ0, reported similar values in a study that investigated the mechanical performance of recycled aggregates derived from EM. Other studies have also reported the density for recycled aggregates obtained from ready mixed concrete waste within the range 1.65-2.72% [11,16,20,26]. It can also be mentioned that Norwegian rocks typically have a density within the range of 2.65-3.10 g/mL [16].…”

“…The authors, however, mentioned that the interface transition zone of concrete produced with RCSA improved and this contributed to the resistance to water penetration. Similar procedure of applying dry washing technology with high water absorbing polymers has gained interest in Norway and a study demonstrated the Los Angeles strength of RCSA to be 25% by applying this type of polymer [16].…”