Structural use of concrete with recycled aggregates
The use of crushed construction and demolition waste as recycled aggregates in partial or full replacement of natural aggregates provides a sustainable solution that saves land space, reduces the transportation cost and decreases the consumption of natural resources. Recycled aggregates can be divided in different types, e.g. mixed aggregates, normal quality recycled concrete aggregates (RCAs) and high quality RCAs based on the properties of the materials. Presently, all types of recycled aggregates are mainly used in low-grade applications such as sub-foundations and foundations in the road work. High-value-added applications of recycled aggregates, especially for high quality RCAs are required. In this PhD research, an extensive study on the utilisation of high quality RCAs in precast structural concrete components will be conducted.
The incorporation of recycled aggregates in concrete will lead to a different behaviour of the concrete in comparison to conventional concrete with natural aggregates. To meet the related requirements for structural concrete, performance based design for concrete with recycled aggregates will be developed. The influence of various factors such as recycled aggregates content, mixing method, curing condition, type of cement, water reducing admixtures will be investigated. Various laboratory tests on the material behaviour of concrete with recycled aggregates including strength, modulus of elasticity, shrinkage and creep behaviour of the different concrete mixtures will be carried out. In addition, the use of different types of fibres, e.g., steel fibres, polypropylene fibres to enhance the properties of concrete with recycled aggregates will be studied.
Experimental study on structural elements with recycled aggregates will also be performed. Finally, analysis procedure and design concepts for precast concrete structural elements containing recycled aggregates will be developed taking into account the effect of recycled aggregates.