Title: Permeation Properties of Recycled Concretes Containing Recovered Aggregates

Author(s): Stephen O. Ekolu

Publication: Symposium Paper

Volume: 326

Issue:

Appears on pages(s): 42.1-42.8

Keywords: recycled concrete, brick, demolition rubble, sorptivity, water absorption, oxygen permeability, durability, porosity

DOI: 10.14359/51711024

Date: 8/10/2018

Abstract:

This paper reports an experimental study conducted to assess durability characteristics of concretes made using different types of recycled aggregates. Different types of recycled coarse aggregates comprising natural dolomite (DOL), crushed concrete (RCA), demolition rubble (RUBL) and brick (BRIC) were studied using concrete mixtures of water-cement ratios (w/c) = 0.60 and 0.45 containing 100% of the recycled stone. The same type of crushed natural sand was used in all the mixtures. In addition to compressive strength and workability, water sorptivity and oxygen permeability (K) properties of the concretes were measured. It was found that the recycled aggregates showed higher porosity than the control crusher dolomite aggregate. Oxygen permeability results of the recycled aggregate concretes were of the same order of magnitude, giving about K = 2.0 x 10^-10 m/s (6.56 x 10^-10ft/s). Recycled brick aggregates produced concretes of consistently higher permeability and water sorptivity than the others. The oxygen permeability values for the various recycled aggregate concretes increased in the order KDOL < KRCA < KRUBL < KBRIC. Permeability of brick aggregate concrete was four times higher than that of control dolomite concrete. This relatively adverse influence of recycled brick on concrete properties is attributed to its highly porous characteristics.