Title: Delayed Ettringite Formation in Concrete Containing Limestone Filler

Author(s): Mohammad Aqel and Daman K. Panesar

Publication: Materials Journal

Volume: 115

Issue: 4

Appears on pages(s): 565-574

Keywords: compressive strength; delayed ettringite formation; freezing and thawing; limestone filler; self-consolidating concrete; steam curing

DOI: 10.14359/51702013

Date: 7/1/2018

Abstract:
This paper investigates the influence of cement and limestone filler (LF) particle size on self-consolidating concrete expansion due to delayed ettringite formation. LF was used to replace 15% of the cement. All concrete mixtures had 5% silica fume and a water-cement ratio (w/c) of 0.34. The concrete mixtures were steam-cured at a maximum temperature of 55, 70, and 82°C (131, 158, and 180°F). The results showed that LF increases the 16-hour compressive strength when concrete was steam-cured at 55°C (131°F). LF did not have any significant adverse effect on the later-age (28- to 300-day) compressive strength, regardless of steam-curing temperature. The permeability of concrete at 28 and 300 days was reduced in the presence of LF. Steam-cured concrete mixtures at 82°C (180°F) expanded and developed microcracks after 300 days. This expansion and cracking caused a significant reduction in the freezing-and-thawing resistance compared to steam-cured concrete mixtures at 55°C (131°F). Concrete mixtures made with LF and steam-cured at 70 and 82°C (158 and 180°F) showed lower expansion due to delayed ettringite formation after 300 days compared to concrete mixtures made without LF. This reduction was caused by the reduction in cement content and reduction in concrete permeability when LF was used.