The demand to consider novel sustainable material development within the concrete construction industry is growing. To consider this trend, the overarching goal of this research paper is to support sustainable concrete development with novel ideas. Recognizing that the bulk of research into demolished concrete waste currently pertains to Recycling Concrete Aggregates (RCA) for conventional aggregate substitution, this research paper Instead considers this waste stream for the development of Reclaimed Concrete Cement (RCC). Received concrete demolition waste was sieved as predominately fine RCA (less than 4.75 mm by grain size). A procedure was then developed based on thermo-mechanical analysis of the RCA which justified an optimum preparation for this particular RCC. The procedure also reduced deleterious aggregates which were present within the waste stream. Bench-scale concrete cylinders were prepared according to a conventional 50 MPa structural grade concrete mix design. Trial mixes were considered with RCC replacing conventional cement by mass percentage (0, 20, 30, 50, and 100%). Results indicated that RCC substitutions of less than 20% by mass had no negative impact on mechanical strength properties, and a structural grade concrete could be achieved with up to 50% cement substituted RCC by mass. A short application exercise of this RCC mix is described herein as well as suggested applications and future research directions. It must be acknowledged that the thermo-mechanical procedure used in this study for developing RCC is currently challenging to adapt to conventional practice without adjoining novel cement making technologies. Despite this, the research provides a good introduction to the potential use and development of RCC in sustainable concrete mix designs in the future.

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Conference 6th International Conference on Engineering Mechanics and Materials 2017
Citation
Gales, J, & Li, M. (Mina). (2017). Developing reclaimed concrete cement for structural grade sustainable concretes. In 6th International Conference on Engineering Mechanics and Materials 2017 (pp. 293–301).