Performance investigation of demolition wastes-based concrete composites

Due to man-made and natural anomalies occurring on planet Earth, there are a lot of destroyed cities, settlements and houses. The issue is how to rebuild these cities and how to use parts of the destroyed buildings and structures in making greener concrete. This paper aims to study the efficiency and effect of using concrete demolition wastes on the microstructure of greener concrete composites. We prepared demolition wastes-based concrete composite containing a greener supplemental cementing binder (GSCB) and fine aggregates of the previously produced concretes with high mechanical properties. The design of the compositions was determined by taking into account the law of affinity of microstructures of greener concretes. We studied the strengths, microstructural, morphological and thermal properties of raw materials and concretes at 28 days of curing. The dense microstructure was examined via the use of Portland cement and hydration products, which partially included previously unreacted clinker minerals presented in concrete waste and activated during its grinding. Results showed that replacing up to 20 % of Portland cement with the demolition waste of concrete structures as a GSCB improves compressive strength for different concrete applications. This is ensured by the affinity of the microstructure of concrete waste and newly synthesized concrete.