Title: Efficiency of Using Recycled Coarse Aggregate for Internal Curing of Blended Cement Concretes

Author(s): Troian Viacheslav, Gots Volodymyr, Bruno Alex, Panek Rafał, and Flatt Robert J.

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 916-929

Keywords: internal curing, recycled aggregate concrete, rheology, workability

DOI: 10.14359/51742018

Date: 6/18/2024

Abstract:
It is known that the use of recycled coarse aggregates (RCA) can raise a variety of problems, which are mainly due to the porosity of the old mortar contained in RCA. One of the simpler ways to solve these problems is the pre-wetting of RCA, which allows not only to minimize disadvantages but also to obtain the advantages associated with the effect of internal curing. Undoubtedly, the strongest positive effect of pre-wetted RCA is on the rheology of recycled concrete. But there are also possible positive effects of internal curing for strength and durability of blended cement concretes, which require longer curing times compared to normal Portland cement concrete. In this paper, we mostly study the influence of porous RCA on the rheology of cement paste, based on slag cement with a 75% slag content. For this purpose, the absorption properties of RCA of different sizes were studied. From this, mathematical dependences of the workability of cement systems on w/c and time could be obtained. These further underline the positive effect of pre-wetting of RCA with regard to retaining the workability of cementitious systems. This lays the basis for a broader study of pre-wetting RCA on the rheology of mixtures, strength, and durability to be covered in future publications.