Development of Concrete Mixtures Based Entirely on Construction and Demolition Waste and Assessment of Parameters Influencing the Compressive Strength
in: RILEM Bookseries, Springer International Publishing Ag, pp.510-520, 2023
- Publication Type: Book Chapter / Chapter Research Book
- Publication Date: 2023
- Doi Number: 10.1007/978-3-031-33211-1_45
- Publisher: Springer International Publishing Ag
- Page Numbers: pp.510-520
- Keywords: Compressive strength, Construction and demolition waste, Geopolymer concrete, Recycled concrete aggregate
- Ankara Yıldırım Beyazıt University Affiliated: No
Abstract
Demolition and reconstruction of degrading structures alongside with the repetitive repair, maintenance, and renovation applications create significant amounts of construction and demolition waste (CDW), which needs proper tackling. The main emphasis of this study has therefore been placed on the development of concrete mixtures with components (i.e., aggregates and binder) coming entirely from CDW. As the binding phase, powdered CDW-based masonry units, concrete and glass were used collectively as precursors to obtain geopolymer binders, which were then incorporated with CDW-based fine and coarse concrete aggregates. Together with the entirely CDW-based concretes, designs were also proposed for companion mixtures with mainstream precursors (e.g., fly ash and slag) occupying some part of the CDW-based precursor combination. Sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and calcium hydroxide (Ca[OH]2) were used at various concentrations and combinations as the alkaline activators. Several factors that have impact on the compressive strength results of concrete mixtures, such as mainstream precursor replacement rate, alkaline molar concentrations, aggregate-to-binder ratios and curing conditions, were considered and these were also backed by the microstructural analyses. Our results showed that through proper optimization of the design factors, it is possible to manufacture concrete mixtures entirely out of CDW with compressive strength results able to reach up to 40 MPa under ambient curing. Current research is believed to be very likely to promote more innovative and up-to-date techniques to upcycle CDW, which are mostly downcycled through basic practices of road base/sub-base filling, encouraging further research and increasing the awareness in CDW issue.