Cement Paste Reference Material (SRM2492) Shelf-Life Extension

Published

September 30, 2016

Author(s)

Alex Olivas, Chiara C. Ferraris, Brian Lang, Jennifer Richter, Raissa Ferron

Abstract

Cement-based materials (e.g. cement paste, mortar and concrete) are complex rheological fluids that display time-dependent and shear-dependent rheological behavior. Over the years, various concrete rheometers have been proposed and made available commercially; however, there is no method to calibrate them. Furthermore, typical calibration fluids used in commercial rheometers are not well suited for the concrete rheometer calibration due to their high cost and they are Newtonian (i.e., not a complex fluid). Therefore, there was a clear need for a reference material specifically designed for concentrated, granular suspensions, such as cement paste, mortar and concrete; this need led to the development of a new series of reference materials for calibration of devices used in cement-based suspension rheological testing. The reference material to simulate cement paste, SRM 2492, was composed of a fine limestone powder in a corn syrup matrix. While the ranking of mixtures tested using these rheometers tend to match, the absolute values for the rheological properties of the mixtures evaluated with different rheometers are not well correlated [1, 2]. Additionally, due to microbial growth in the paste matrix, the shelf life of standard reference material 2492 was limited to 7 d. This paper presents the results of a study to analyze how to minimize microbial growth within the paste matrix. Various biocides that extend the shelf-life of the reference material were examined, with the most promising method being sodium propionate, a non-toxic chemical. Furthermore, recommendations to improve the storage of SRM are provided to extend the usable shelf life.

Citation

Technical Note (NIST TN) - 1934

Report Number

1934

NIST Pub Series

Technical Note (NIST TN)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.TN.1934

Local Download

Keywords

Rheology, Reference Materials, Biocide, Microorganisms, Microbes

Citation

Olivas, A. , Ferraris, C. , Lang, B. , Richter, J. and Ferron, R. (2016), Cement Paste Reference Material (SRM2492) Shelf-Life Extension, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.TN.1934, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920962 (Accessed October 31, 2024)