Effects of spatial structure of superabsorbent polymer particles on autogenous shrinkage behavior of cement paste

Title: Effects of spatial structure of superabsorbent polymer particles on autogenous shrinkage behavior of cement paste
Author(s): S-I. Igarashi, N. Aragane, Y. Koike
Paper category : conference
Book title: International RILEM Conference on Use of Superabsorbent Polymers and Other New Additives in Concrete
Editor(s): O.M. Jensen, M.T. Hasholt and S. Laustsen
Print-ISBN: 978-2-35158-104-9
e-ISBN: 978-2-35158-105-6
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 137 - 147
Total Pages: 11
Nb references: 9
Language: English

Abstract: Superabsorbent polymer (SAP) was used for reducing autogenous shrinkage in cement paste. Reduction in the shrinkage was discussed in relation to spatial structure of the SAP particles. The spatial structure was evaluated by some second-order functions in spatial statistics. Hydration of cement in the vicinity of the SAP particles was investigated by microhardness testing. When internal water to compensate chemical shrinkage at the maximum degree of hydration was incorporated into cement paste with a w/c of 0.25, the SAP particles were distributed at random and uniformly such that a mean distance from an arbitrary point in the cement paste matrix to the nearest surface of SAP was about 400µm. A nearest neighbor point can be found within the distance of 2000µm from a point representing the SAP. The microhardness measurement around the SAP particles suggested that the region protected from self-desiccation extended at most for about 200µm around the surface of SAP. These characteristic distances evaluated by the spatial functions suggest that there existed a large area in which self-desiccation could not be compensated by the internal water. However, remarkable reduction in the shrinkage was observed in the specimens with SAP. A concept of coverage of the whole matrix with the protected regions should be reconsidered if the purpose of testing the shrinkage is to evaluate performance of a SAP as an internal curing material.

Online publication: 2010-10-04
Publication type : full_text
Public price (Euros): 0.00