Crushed concrete aggregates in new structural concrete. Part I

The use of crushed concrete debris from old buildings as aggregate in new concrete structures is still very limited, despite the seemingly obvious prospects for such an approach. The main reason for this is the lower quality of crushed concrete aggregates (CCA) compared to natural aggregates, which worsens the performance of CCA concrete: it reduces its strength, increases porosity and permeability and can ultimately lead to a shorter service life of the structure. However, decades of research, combining laboratory development and longterm monitoring of ÑÑA concrete structures, as well as advances in modern construction chemistry, have yielded encouraging results. Methods to improve the properties of concrete with ÑÑA are currently being developed in two directions: 1) preliminary physical or chemical treatment of aggregates from crushed concrete, increasing their quality; 2) optimization of concrete mixture composition with the help of highly effective mineral and plasticizing additives, allowing to make the structure of concrete with CCA denser. In the first part of the article the origin, classification of CCA and their influence on the basic properties of newly manufactured concrete mixtures and concretes are considered.

Author: A.S. Brykov, K.O. Chugunova

Section: Waste utilization

Keywords: concrete, recovered concrete aggregate, durability