REUTILIZATION OF RECYCLED CONCRETE AS CONCRETE COARSE AGGREGATE

Gamal, Ayman; A. Mirza, Faiz

doi:10.21608/erjm.2004.82604

REUTILIZATION OF RECYCLED CONCRETE AS CONCRETE COARSE AGGREGATE

Document Type : Original Article

Authors

Ayman Gamal ¹
Faiz A. Mirza ²

¹ Engineering Materials Dep., Faculty of Engineering, Zagazig University, Zagazig, EGYPT.

² Civil Engineering Dep., Faculty of Engineering and Islamic Arch. Umm - Elqura University, Maka, SUADI ARABIA

10.21608/erjm.2004.82604

Abstract

Demolished concrete which became million tons annually, so reuse of these concrete represents
a new source of aggregate. The aim of this paper is to study experimentally the effect of using
recycled crushed concrete as a coarse aggregate in concrete mix. The main variables considered in
this study were the recycled concrete aggregate (RCA) content (0, 25, 50, 75 and 100% by weight)
as substitution of natural aggregate (NA) and Cement content (250, 300, 350 and 400 kg/m”). The
strength development under compressive and tensile stresses was measured. Test results showed
that the behavior of concrete that contained recycled concrete aggregate and that contained natural
aggregate are nearly the same under compression and tension stress. The compressive strength
increases by increasing the recycled aggregate content from 25% up to 100%. The tensile strength
has optimum value at 50% recycled concrete aggregate content. Also it was found that the
compressive and tensile strengths of recycled concrete aggregate specimens were increased by
increasing cement content from 250 kg/m² up to 400 kg/m'. This is mainly due to the high
reactivity of the recycled concrete and cause alkali-silica bi-reaction.

Keywords