A Comparative Study of Control and Recycled Aggregate Concrete Containing Silica Fume and Steel Fibres

Abstract

The growing environmental concerns and proper disposal of construction and demolition waste is a challenge for construction industry. The use of demolition waste as a resource for recycling or recovery is gaining grounds in many countries. The proper selection and processing of demolition waste can be helpful in producing concrete. Production of concrete using recycled aggregate concrete has many benefits, such as, proper management of demolition waste, natural aggregates shortage is addressed, reduction in transport cost of raw materials. This thesis, aims to find the possibility of the structural usage of recycled aggregate concrete as alternative or mixed with natural aggregates, by conducting a comprehensive laboratory investigation for better understanding of mechanical and durability properties of recycled aggregate concrete. A mix proportion was established to produce twelve different concrete mixtures using 0%, 50% and 100% of recycled coarse aggregate with and without silica fume and steel fibre. The water-cement ratio of 0.42 is used. Control mixture using natural aggregate showed better results compared with the mixture of using recycled aggregate. Results shows that more recycled aggregate is used, the compressive strength of concrete decreases. However, recycled aggregate used with silica fume and steel fibres showed improved strength and durability. By using supplementary materials it was possible to achieve higher mechanical properties of the RAC containing 100% recycled aggregate than that of control mixture concrete.