Reclaimed concrete material (RCM), also occasionally referred to as “recycled concrete pavement” or “crushed concrete,” is a material composed of graded aggregates bound together by a hardened cementitious paste. The aggregates in the material make up anywhere from 60 to 75 percent of the concrete’s total volume.
Usually RCM is made after the demolition of Portland cement concrete, which is most frequently used for building roads, paved surfaces and some types of structures. When crews complete road reconstruction, demolition or utility excavations, they’ll take the concrete they pull up and send it for concrete recycling in Toledo, OH, which results in RCM. The RCM will generally be removed with a backhoe or payloader and then sent off site in dump trucks. That excavation process may include a significant amount of soil material from the subbase, as well as asphalt pavement, which is why RCM doesn’t just feature Portland cement concrete, but also some soil and bituminous concrete.
Once excavated, the concrete that will be recycled gets taken to a facility where it will be stockpiled, and ultimately processed. At the processing facility, the RCM goes through the processes of screening, crushing and ferrous metal recovery. During this process, steel can be removed and recycled itself.
How is RCM used?
RCM is most commonly used in highway settings. It is most frequently found as an aggregate substitute in the construction of pavement, and that includes how it is used in base and engineered fill, as well as various Portland cement concrete applications. It can also be used as an aggregate material in flowable fill, certain types of surface treatments and some hot mix asphalt concrete.
If it is to be used as an aggregate, the RCM must be processed thoroughly to remove as much steel and foreign debris as possible. Reinforcing steel is commonly found in RCM, and can be removed before it gets loaded and hauled to a processing plant.
However, processing plants generally account for the need to remove steel as well, and will have both a primary and secondary crusher. The jaw crusher that serves as the primary crushing tool breaks the reinforcing steel away from the concrete, and brings the rubble down to a size of no more than three to four inches in diameter. As the material gets sent over to the secondary crusher, the steel gets removed by an electromagnetic separator. The secondary crushing process then breaks down the RCM even further, before it gets screened to the ideal gradation for the application in which it will be used.
Processed RCM has a rougher surface texture than other types of aggregates, as well as a lower specific gravity and a higher water absorption. It is angular in its shape, and as the particle size of RCM gets smaller, you’ll also notice decreases in specific gravity and increases in absorption.
For more information about the use of recycled concrete material in Toledo, OH, we encourage you to contact the team of paving professionals at Klumm Bros. today.
Categorised in: Recycling