Cement sensors with acoustic bandgaps using carbon nanotubes

Abstract

Cement is widely used in wellbores to stabilize the steel casing used in wellbore operations for oil and gas production, enhanced geothermal systems and carbon sequestration, and to limit fluid movement between sub-surface strata. Flaws such as microcracks in wellbore cement can lead to leakage along the wellbore compromising wellbore integrity. There is an increasing need for methods to monitor cement crack propagation in wellbore environments. In this study, we develop and report the first cementitious sensors capable of exhibiting high frequency acoustic bandgaps (ABGs) using carbon nanotubes (CNTs). Computational simulations of a sensor unit cell are used to design cement-multi walled carbon nanotubes (MWCNTs) sensors that show a wide bandgap. When the cement-MWCNTs sensors is embedded in cement specimens, bandgaps were measured experimentally under 300 kHz and under 600 kHz, consistent with the computationally predicted bandgaps in the range of 290–360 kHz, 410–460 kHz and 515–585 kHz. These bandgap features were absent in homogeneous cement specimens. X-ray tomographic reconstructions showed microscopic debonding at cement-MWCNTs sensor interface. Frequency response analysis of a three-dimensional computational model indicated a shift of frequency of minimum transmission due to the interface debonding, but no perturbation of bandgap response was observed. The cement-MWCNTs sensors developed in this study show the potential of a packed CNT inclusion material in cementitious matrix to create ABGs in a cement matrix.

Development and Characterization of a Sustainable Bio-Polymer Concrete with a Low Carbon Footprint

“…Hence, for the rest of the experiments, the 16 vol.% PU and 4.0 wt.% benzoic acid were selected as the reference mix to investigate the impact of benzoic acid and COOH-functionalized MWCNTs on the behavior of the BPC. Before mixing, the polyol was nano-modified utilizing COOH-functionalized MWC-NTs at an optimum dosage of 0.5 wt.% of binder; the optimum dosage was chosen based on previous work [9]. The dispersion procedure was performed following previous work done by Douba et al [10].…”

“…Before mixing, the polyol was nano-modified utilizing COOH-functionalized MWCNTs at an optimum dosage of 0.5 wt.% of binder; the optimum dosage was chosen based on previous work [ 9 ]. The dispersion procedure was performed following previous work done by Douba et al [ 10 ].…”

“…To enhance the properties of PUs, fillers have been considered as a viable alternative [ 6 , 7 ]. Multi-walled carbon nanotubes (MWCNTs) have extensively been utilized in the preparation of polymer nanocomposites due to their high flexibility, low mass density, high aspect ratio, and exceptional mechanical and electrical properties [ 6 , 8 , 9 ]. Chemically modified MWCNTs, such as carboxyl- (COOH) functionalized graphitized MWCNTs (COOH-functionalized MWCNTs), have been widely used to reinforce polymers due to their high adhesion efficiency [ 3 , 10 ].…”

Auxetic hybrid metamaterial with tunable elastic wave bandgap

“…In 2000, Liu et al [18] reported local resonance phononic crystal, the structure can manipulate large wavelength acoustic energy by small size structure [19], broadening the study of low-frequency bandgap [20]. The emergence of the local resonance mechanism broke through the limitations of the traditional Bragg scattering bandgap [21,22] and promoted the research of the local resonance mechanism to generate the bandgap [23,24]. For example, He et al [25] proposed a column structure of locally resonant elastic metamaterial based on composite materials.…”

An Undergraduate Research Experience: A Computational Approach to Understand Acoustic Bandgap Features in Cement

“…A band structure is a graph that describes the propagation of waves at certain frequencies through a parametric sweep, hence showing the band gap. Research has been done to develop equations that determine wave propagation, speed of sound, filling fractions and more equations that govern the design of these materials [6][7][8]. The equations used for our particular simulations are listed in the next section.…”