Title: Effect of Slag Cement on Drying Shrinkage of Concrete
Author(s): Jiqiu Yuan, Will Lindquist, David Darwin, and JoAnn Browning
Publication: Materials Journal
Appears on pages(s): 267-276
Keywords: bridge decks; cracking; curing; dry free shrinkage; internal curing; slag cement
The effect of a partial replacement of cement with slag cement on free shrinkage is evaluated for curing periods between 3 and 28 days. Mixtures include concrete containing different replacement levels of slag cement (30, 60, and 80% by volume) cast with limestone, granite, or quartzite coarse aggregate. Comparisons are only made with mixtures having the same paste content (by volume) and water-cementitious material ratio. The study shows that a partial replacement of cement with slag cement decreases free shrinkage compared to mixtures containing 100% portland cement; the reduction is greatest at early ages and is improved as the replacement level is increased. Increasing the curing period decreases free shrinkage for mixtures with and without slag cement. When slag cement is used in conjunction with a porous limestone coarse aggregate, where internal curing is provided by the water stored in the pores of limestone, an even greater reduction in free shrinkage is observed compared to mixtures cast with low-absorption coarse aggregate.