Title: Superabsorbent Polymers to Mitigate Autogenous Shrinkage of Cement Mortar

Author(s): Christof Schrofl and Viktor Mechtcherine

Publication: Symposium Paper

Volume: 288

Issue:

Appears on pages(s): 1-14

Keywords: autogenous shrinkage; cement pore solution; internal curing; high-performance concrete; kinetics of absorption and desorption; neutron radiography; superabsorbent polymers (SAP).

DOI: 10.14359/51684234

Date: 9/14/2012

Abstract:
Superabsorbent polymers (SAP) made of acrylic acid and acrylamide were studied as chemical admixtures for mitigating autogenous shrinkage of high-performance concrete or mortar, respectively. The absorptivity of the particles in saline solutions and in cement pore solution was investigated. Ca2+ in the alkaline solution modified the absorp¬tivity essentially, which closely depended on the polymer structure. Furthermore, the release of internal curing water from SAP particles into the hardening cement-based matrix was monitored by neutron radiography. The kinetics of uptake and release of cement pore solution by SAP and hence, their molecular structure, could be linked with their efficiency in mitigating autogenous shrinkage of a high-strength mortar. Finally, the compressive strength of these mortars was determined. The addition of SAP had no negative effect, but could even lead to an increase in the compressive strength.