Title: Innovative Admixtures to Address Operational and Sustainability Issues with Returned Concrete
Author(s): Charles Nmai, Chris Eagon, John Luciano
Publication: Symposium Paper
Appears on pages(s): 325-336
Keywords: backfill; base material; chemical admixtures; crushed concrete; hydration stabilizer; operational costs; returned fresh concrete; road base; sustainable construction
In the late 1980s, an innovative hydration-stabilizing admixture was introduced to help concrete producers effectively extend the working time of fresh concrete mixtures for challenging applications, particularly, in hot weather or long time-to-discharge applications. The hydration-stabilizing admixture also provided concrete producers with a means of managing returned concrete to address environmental issues associated with concrete waste. In recent years, admixtures that allow concrete producers to convert returned concrete into a very low-strength granular material that can be used for construction backfill, road base, or in other applications have been introduced. Together with the hydration-stabilizing admixture, concrete producers can now use chemical admixtures to significantly reduce concrete waste. In this paper, the operational and sustainability benefits of the hydration-stabilizing admixture and a new one-component engineered polymer admixture that facilitates the beneficial reuse of returned fresh concrete are presented and discussed.