Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
Composites Science and Technology, Volume 75, 11 February 2013, Pages 77-83.
Agathe Robisson, Sudeep Maheshwari, Simone Musso, Jeffrey J. Thomas, Francois M. Auzerais, Dingzhi Han, Meng Qu, Franz-Josef Ulm.
Schlumberger-Doll Research, 1 Hampshire St., Cambridge, MA 02139, United States and
A.T. Kearney, 7 Times Square #36 New York, NY 10036, United States and
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Abstract
This paper describes a novel reactive composite material comprised of hydrogenated nitrile butadiene rubber (HNBR) compounded with slag cement. The composite initially looks and behaves like rubber, but when exposed to water it simultaneously swells and stiffens due to hydration of the cement component. The material eventually reaches a stiffness that is intermediate between that of HNBR and hydrated cement, while maintaining a relatively large ductility that is more characteristic of rubber. This behavior, which is ideal for sealing applications, differentiates this material from conventional swellable materials that become less stiff upon swelling. The development of this new type of material was motivated by the requirements of oilfield zonal isolation, where alternatives to cement are needed for some challenging sealing applications. A mechanism for the swelling and stiffening of the reactive composite is proposed: water diffuses into the HNBR matrix and is converted to bound water through hydration reactions with the cement, causing the effective solid filler content of the composite to increase. A model is proposed that treats the composite as a cellular solid with a continuous filler phase (hydrated cement). This model is able to reproduce the observed increase in the elastic modulus with time during exposure to water.
