Influence of self-healing, mixing method and adding silica fume on mechanical properties of recycled aggregates concrete

The objective of this study is to investigate the properties of concrete made with recycled concrete coarse aggregates. Two grades of concrete compressive strength are considered. Results showed reduction in concrete properties (compressive strength, tensile strength, bond strength and porosity) of concrete containing recycled aggregates especially at higher contents. Hence, this study proposed three techniques to enhance properties of recycled aggregates concrete. These techniques involve process of self healing of recycled aggregates, mixing method and adding silica fume. Self healing, by immersing recycled aggregates in water up to 30 days, improved mechanical properties of recycled aggregates concrete especially for low cement content. Mixing water, cement, addition and recycled aggregates then natural sand and natural coarse aggregates were added, two stages mixing approach, enhance properties of recycled aggregates concrete. Adding 10.0% silica fume as cement addition to recycled aggregates concrete enhanced properties of concrete.

► Compressive strength, tensile strength, bond and porosity of recycled concrete aggregates were studied.
► Self-healing, mixing method and adding silica fume were used to improve the properties of recycled aggregates concrete.
► Self healing process of recycled aggregates improved properties of recycled concrete aggregates.
► Mixing method of recycled concrete aggregates has pronounced effect on properties of recycled concrete aggregates.
► Adding 10% silica fume to recycled aggregates concrete enhances properties of recycled concrete aggregates.