Page 494 - New Trends in Eco efficient and Recycled Concrete

444 New Trends in Eco-efficient and Recycled Concrete

heterogeneous material. The number of possible techniques used to establish the
microstructural features of cementitious products is vast and continues to increase,
allowing to explore and explain microstructural details at several length-scales.
The main limitations associated to the most common RAs, those produced from
concrete or CDW, are related to the presence of weaker materials such as mortar or
brick. These materials have higher porosity than their natural counterparts and are
deleterious to the ITZs established with new paste. The performance of RA con-
crete thus mostly depends on the quality and origin of the RAs used. RAs morpho-
logical, physical and chemical properties, together with the presence of light and
heavy contaminants are key features that will influence microstructural develop-
ment and, thus, the macroscopic behaviour of RAC.

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