Title: Self-Restraining Shrinkage Ultra-High-Performance Concrete: Mechanisms and Evidence

Author(s): Ahmed M. Soliman and Moncef L. Nehdi

Publication: Materials Journal

Volume: 110

Issue: 4

Appears on pages(s): 355-364

Keywords: autogenous; hydrated skeleton; passive internal restraint; shrinkage.

DOI: 10.14359/51685782

Date: 7/1/2013

Abstract:
This paper describes a new concept for reducing early-age shrinkage in hydrating cement-based materials. The concept consists of adding a partially hydrated cementitious material (PHCM) as a concrete admixture. The added PHCM stimulates the formation of a hydrated cement paste structure and provides microcrystals of hydration products, which act as passive internal restraining clusters within the fresh concrete. The passive restraining system thus developed resists bulk deformations, leading to lower shrinkage. In this paper, the concept of a self-restraining shrinkage system is proposed and discussed, and its effect is examined experimentally including compressive strength, setting time, heat of hydration, autogenous shrinkage, thermal analysis, nuclear magnetic resonance, and scanning electron microscope (SEM) micrograph analysis. Experimental results indicate a high potential for producing self-restraining shrinkage concrete. In particular, using concrete returned to batch plants and intended for disposal as a PHCM, with sufficient precautions to maintain the quality of concrete, can yield significant economical and environmental benefits.