A New Technology for Full Replacement of Natural Aggregates with Bioremediated Recycled Aggregates and Its Lifecycle Assessment

Abstract

The problem of construction and demolition wastes can be mitigated by recycling them as aggregates in concrete. However, high absorption and poor interfacial properties due to the attached mortar from old concrete use a major weakness resulting in only a partial replacement of natural aggregates with the recycled ones. This paper discusses a technique, bioremediated recycled aggregates (BRA), to bring their performance at par with the natural aggregates (NA). A biocement treatment has been applied to strengthen the attached mortar. The performance concrete with NA and 100% BRA is assessed for strength, water absorption, microstructure (using SEM with EDS) and micromechanical properties (using nanoindentation). It is observed that bio treatment recovers the performance of recycled aggregates at par with that of NA. The lifecycle analysis has demonstrated that BRA is clearly more sustainable than NA.