Title: Effect of High Levels of Fines Content on Concrete Properties

Author(s): Amnon Katz and Hadassa Baum

Publication: Materials Journal

Volume: 103

Issue: 6

Appears on pages(s): 474-482

Keywords: aggregate; hardened concrete; workability

DOI: 10.14359/18226

Date: 11/1/2006

Abstract:
The content of fines (particles smaller than 0.075 mm [No. 200] mesh) in aggregates used for the production of concrete is generally limited by most standards worldwide. In the current study, the effect of the addition of fines to normal-strength concrete at levels of up to 227 kg/m3 (383 lb/yd3) was studied in concrete mixtures prepared with constant workability. It was found that as long as workability can be controlled by reasonable amounts of admixture, the addition of fines improves concrete strength by as much as 30%, somewhat reduces the carbonation rate, and slightly increases the volume changes of fresh and hardened concrete. When high dosages of admixture were required to maintain workability due to the presence of large amounts of ultra-fine particles (less than ~5 micron), properties of the concrete were seriously affected.