Title:
Effects of Hauling Time on Air-Entrained Self-Consolidating Concrete
Author(s):
Nader Ghafoori and Mary Barfield
Publication:
Materials Journal
Volume:
107
Issue:
3
Appears on pages(s):
275-281
Keywords:
admixtures; air entrainment; air void; hauling time; selfconsolidating concrete
DOI:
10.14359/51663756
Date:
5/1/2010
Abstract:
Self-consolidating concrete (SCC) is a highly flowable concrete that is characteristically sensitive to mixing and hauling variables such as transportation time. In real-world applications, lengthy hauling times are often necessary for transportation to the job site and can result in deviations in the fresh properties of SCC. In this investigation, air-entrained SCCs were developed at a constant water-to-cementitious material ratio (w/cm) of 0.40 and air content of 6% for three distinct slump flows of 559, 635, and 711 mm (22, 25, and 28 in.). Test results revealed that the slump flow losses up to 39% were recorded after 90 minutes of hauling time. The air content increased with hauling time, ranging from 2.6% to 4.8%. The air void characteristics improved with hauling time, with an average increase in specific surface of 9.5 mm–1 (241.3 in.–1) and an average decrease in spacing factor of 64 μm (0.0025 in.).