Mitigation of autogenous shrinkage in repair mortars via internal curing

Published

October 22, 2015

Author(s)

Dale P. Bentz, Scott Z. Jones, Max A. Peltz, Paul E. Stutzman

Abstract

Repair mortars are being used with increasing frequency to maintain the aging US infrastructure. Durability is a key concern for such repair materials and both their volume stability and bond to the existing concrete are key attributes, the former to avoid excessive cracking of the repair and the latter to ensure that it remains in place as an integral part of the (repaired) concrete structure. This paper examines the volume stability of two commercially available repair mortars by measuring their autogenous deformation to an age of 28 d. Internal curing is examined as a strategy to mitigate the significant autogenous shrinkage encountered for both materials. The performance of pre-wetted lightweight aggregates (LWA), a superabsorbent polymer (SAP), and a superabsorbent polymer-coated sand (AQS) with respect to compressive strength and autogenous deformation are evaluated. Because these three internal curing agents have water absorptions spanning two orders of magnitude, they have differing influences on the proportioning of the mortars and on subsequent performance. In general, when proportioned with the same amount of internal curing water, the mortars based on LWA exhibit the highest compressive strengths and the greatest relative reductions in autogenous shrinkage in comparison to the controls formulated without internal curing.

Citation

Concrete in Australia

Volume

41

Issue

4

Pub Type

Journals

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Keywords

Autogenous shrinkage, internal curing, repair material, strength.

Citation

Bentz, D. , Jones, S. , Peltz, M. and Stutzman, P. (2015), Mitigation of autogenous shrinkage in repair mortars via internal curing, Concrete in Australia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918510 (Accessed October 13, 2024)