Frost-resistance performance and improvement of concrete incorporating coarse mixed recycled aggregate

Mixed recycled aggregates (MRAs) are the majority of recycled aggregates from construction and demolition waste (C&DW). However, due to its diverse composition, when used in concrete manufacture, MRAs generally lead to lower concrete strength and poorer concrete durability than natural aggregates or even recycled concrete aggregates (RCAs). To improve the recycling and reusing of C&DW, the research aims at understanding the frost-resistance performance of concrete incorporating mixed recycled aggregates, overcoming technical problems to promote the application of MRAs in concrete under the freeze-thaw environment. The research mainly focuses on physical and mechanical properties, internal damage and surface scaling evaluation, and frost-resistance based mix proportion optimisation and the frost- resistance improvement through adding fibres. Parameters in the research are supposed to be water compensation ways, water to cement ratios, air entrainments, volumes of fibres, etc.