Title: Characteristics of Concrete Containing a Shrinkage-Reducing Superplasticizer for Ultra-High-Strength Concrete
Author(s): T. Sugamata, T. Kinoshita, M. Yaguchi, and K. Harada
Publication: Symposium Paper
Appears on pages(s): 51-66
Keywords: autogeneous shrinkage strain; compressive strength; setting time; shrinkage reducing; superplasticizer; ultra-high-strength concrete
In Japan, the applications of ultra-high-strength concrete having a design strength of 100 MPa are increasing. Such high-strength concrete offers a number of advantages: reduced column cross section for greater useable floor area; broader elasticity range for suppression of earthquake-induced cracking; and longer service life to meet recent demand in Japan. The potential for the use of this class of concrete will increase in Japan. However, ultra-high-strength concrete of this strength range suffers from critical autogeneous shrinkage strain due to its low water-binder ratio (Silica fume is normally used in such the strength range in Japan). The authors developed a shrinkage-reducing superplasticizer by mixing a glycol-based shrinkage reducing component with a superplasticizer for ultra-high-strength concrete developed by the authors, and studied the properties of concrete containing this new shrinkage-reducing SP in this strength range. Compared with plain concrete (without shrinkage reducing component), the shrinkage-reducing SP reduced the autogeneous shrinkage strain by 15 to 30%, and drying shrinkage strain by 3 to 25%. The rate of reduction increased as the W/C decreased and the amount of shrinkage component increased. The authors determined that the new shrinkage-reducing SP is effective in reducing the autogeneous shrinkage strain in ultra-high-strength concrete.