Title: Quantifying the Impact of Internally Cured Concrete on Duration of External Curing

Author(s): L. Bouchelil, R. M. Ghantous, G. Clark, M. N. Goodwin, W. J. Weiss, and M. Khanzadeh Moradllo

Publication: Materials Journal

Volume: 119

Issue: 5

Appears on pages(s): 269-280

Keywords: curing compound; internal curing; lightweight aggregate; neutron radiography; supplementary cementitious materials; wet burlap

DOI: 10.14359/51735980

Date: 9/1/2022

Abstract:
Relatively limited work has been performed to quantify how internal curing influences curing specifications. This paper examines the performance of internally cured mixtures (made using fine lightweight aggregates) compared to conventional concrete cured with wet burlap and curing compounds. Mortar mixtures were prepared using ordinary portland cement (OPC), fly ash, and silica fume (SF) with water-cementitious materials ratios (w/c) of 0.35 and 0.45. Neutron radiography (NR) was used to determine the nonevaporable water content as a function of curing time and distance from the exposed surface. The curing-affected zone (CAZ) was determined using the nonevaporable water profiles. The CAZ was used to develop equivalent curing durations for conventionally cured and internally cured samples. Internally cured mixtures reduced the depth of the CAZ, especially in the samples with limited external curing durations (reduction up to 15 mm [0.6 in.]). The application of internal curing in all mixtures reduced the duration of external curing by 50 to 60%, except for the internally cured SF samples, which showed a slight reduction. This dramatically impacts the construction schedule.