Title:
Internal Curing - Real World Ready Mix
Production and Applications: A Practical
Approach to Lightweight Modified Concrete
Author(s):
V.H. Villarreal
Publication:
Symposium Paper
Volume:
256
Issue:
Appears on pages(s):
45-56
Keywords:
internal curing; lightweight aggregate; moisture conditioning
DOI:
10.14359/20230
Date:
10/1/2008
Abstract:
The benefits of using lightweight aggregate (LWA) to replace a portion of the normalweight aggregates in concrete mixtures have been investigated by many researchers. The main purpose of this substitution has been to provide a source of moisture for internal curing that will promote more complete hydration of the cementitious materials. The adequate initial moisture conditioning of
the LWA is the most crucial step in the ready mixed concrete production cycle. Once the LWA has been satisfactorily saturated, the potential for field problems is insignificant. Any shortcuts in this fundamental procedure can result in the failure of the concept and reluctance on the part of the concrete contractor to adapt this technology. The problems can range from yield issues to slump loss, segregation, finishability, and pumpability. The slow release of moisture from the lightweight aggregate to the concrete matrix has resulted in the mitigation or elimination of plastic and drying shrinkage cracking, as well as limiting the effects of self-desiccation. Enhanced workability and better
consolidation due to an improved total grading provided by the use of an intermediate aggregate is also evident; contractors have reported that it reduces the total placing time.