LWA Absorption and Desorption: The Influence on the Microstructure and Transport Properties of Internally Cured Mortars

Published

September 1, 2010

Author(s)

Javier Castro, Ryan Henkensiefken, Tommy Nantung, Dale P. Bentz, Jason Weiss

Abstract

The increased propensity for shrinkage cracking in low water-to-cement ratio (w/c) concrete has resulted in the development of new methods that can reduce the risk of early-age cracking, including internal curing. Internal curing can use water-filled lightweight aggregate (LWA) to supply curing water to low w/c paste as it hydrates. Significant research has been performed to determine the effects of internal curing on shrinkage and stress development; however, relatively little detailed information exists about the effects of internal curing on transport properties such as water absorption or ion diffusivity. This study examines the influence of internal curing on absorption of water and the electrical conductivity in mortar specimens. In addition, procedures for determining the absorption and desorption of LWA are also discussed, as this can play a substantial role in determining the volume of LWA that is needed and the amount of curing water that can be supplied to the paste The results indicate that the inclusion of water-filled LWA can increase the long term degree of hydration of the cement paste and reduce both the total porosity and the interconnection of the pore structure of mortar specimens. The sorptivities and electrical conductivities exhibited by these mortars were better than expected. For example, results for an internally-cured mortar with a w/c of 0.30 indicate performance that is consistent with a conventional mortar prepared with a w/c of 0.23 or a paste with a w/c of 0.30.

Proceedings Title

CONSEC'10: Sixth International Conference on Concrete under Severe Conditions, Environment, and Loading

Conference Dates

June 7-9, 2010

Conference Location

Merida, MX

Pub Type

Conferences

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Keywords

Absorption, building technology, desorption, lightweight aggregate, transport.

Citation

Castro, J. , Henkensiefken, R. , Nantung, T. , Bentz, D. and Weiss, J. (2010), LWA Absorption and Desorption: The Influence on the Microstructure and Transport Properties of Internally Cured Mortars, CONSEC'10: Sixth International Conference on Concrete under Severe Conditions, Environment, and Loading, Merida, MX, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=903822 (Accessed October 16, 2025)