Financial assessment of manufacturing recycled aggregate concrete in ready-mix concrete plants

Abstract

Concrete waste is crushed in the present recycling operation to produce crushed concrete (CC), which is mostly used as a road base filler material. The coarse portion of CC, referred to as recycled concrete aggregate (RCA) can be used in structural concrete replacing coarse natural aggregate (NA). The resultant concrete which is referred to as recycled aggregate concrete (RAC), would create a sustainable end use for concrete waste, and reduce the demand for NA, leading to its preservation. However, the concrete industry has been reluctant to embrace production of RAC to its full potential. Beside uncertainty regarding material performance, options available to effectively set up the existing plant operations to manufacture RAC is yet to be explored. This paper attempts to simulate the manufacturing set up to produce RAC by integrating processes involved in concrete waste recycling and readymix concrete (RMC) production environments. It presents a model to evaluate the financial effect of manufacturing RAC in lieu of normal concrete, calibrated with data from RMC manufacturing and recycling plants. Analysis of the response to produce RAC highlights that the price of RAC differ significantly based on the type of RMC manufacturing plant and the cement content of the mix. It is observed that it is highly probable that the price of RAC is 0–10% higher than that of natural aggregate concrete (NAC). Probabilistic estimation of the price difference between RAC and NAC concludes that RMC plants having aggregate feeding mechanism with front-end loader (FEL) would be an appropriate entry for industrial scale manufacturing of RAC.