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Pang X.,Columbia University | Darbe R.,Cementing Applied Science and Processes Group | Meyer C.,Columbia University
ACI Materials Journal | Year: 2012

For the purpose of finding the best fatigue-resistant cement that can be used in oil wells, an experimental investigation of low-cycle compressive fatigue was conducted on oil well cement specimens made with 10 different formulations. A total of nearly 400 samples were tested under both static and cyclic loads. The general deformation behavior of cement paste under cyclic load was obtained. The effect of cement-slurry composition on the fatigue strength of hardened cement paste was the main focus of this study. The main admixtures studied were a foaming agent, a heavyweight agent, elastomer beads, fly ash, and glass fibers. A model that can be used for oil well cement fatigue life or fatigue strength predictions was derived from the experimental data. Comparisons between fatigue behaviors of oil well cements and those of concrete are also presented. Copyright © 2012, American Concrete Institute. All rights reserved.

Pang X.,Columbia University | Meyer C.,Columbia University | Darbe R.,Cementing Applied Science and Processes group | Funkhouser G.P.,Cementing Applied Science and Processes group
ACI Materials Journal | Year: 2013

It is shown in this study that chemical shrinkage tests can be used to evaluate the hydration kinetics of cement cured under different temperatures and pressures. Test results suggest that the effect of curing condition on cement hydration is represented by a scale factor on hydration rate as a function of degree of hydration. Therefore, the hydration kinetic curves of cement at any curing condition can be predicted from those of a reference condition by simple coordinate transformations (that is, scaling the x- and/or y-axis using the scale factor). The dependence of the scale factor on curing temperature and curing pressure is related to the activation energy and the activation volume of the cement, respectively. Test results of five different types of oil well cements in this study give an apparent activation energy ranging from 42.5 to 52.6 kJ/mol and an apparent activation volume ranging from -22.3 to -29.5 cm3/mol. Copyright © 2013, American Concrete Institute.

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