Title:
Strength Development of Concrete Incorporating High Levels of Ground Granulated Blast-Furnace Slag at Low Temperatures
Author(s):
Takashi Miura and Ichiro Iwaki
Publication:
Materials Journal
Volume:
97
Issue:
1
Appears on pages(s):
66-70
Keywords:
blast-furnace slag; compressive strength; concretes; curing; low temperature.
DOI:
10.14359/807
Date:
1/1/2000
Abstract:
This paper presents the effect of mixture proportions and curing method on the strength development of concrete incorporating high levels of ground granulated blast-furnace slag (GGBS) at low temperatures. In this study, the strength development of mortar specimens incorporating GGBS for various mixture proportions and curing methods is investigated. The test parameters include the specific surface area measured by the Blaine method (400, 600, and 800 m2/kg), the level of cement replacement by GGBS (50, 60, 70, and 80% by mass), curing method (water curing, sealed curing, and air curing), and curing temperature (20 and 5 C). The test results demonstrate that the strength development at early ages of GGBS mortar cured at 5 C is lower than that of plain mortar not containing GGBS. Thus, the effect of heat curing on the strength development of GGBS concrete is researched. First, the periods of heat curing suitable for each mixture proportion are determined, then strength development after heat curing is examined. The test results indicate that GGBS concrete with a specific surface area of 400 m2/kg has serious problems with strength development at early ages and low curing temperatures. Heat curing is one way to improve strength development at early ages at lower temperatures. On the other hand, GGBS concrete with a specific surface area of 800 m2/kg has no strength development problem at early ages, even when cured at 5 C, and heat curing seems to have a bad influence on strength development, particularly at later ages.