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This guideline presents methods for the preparation and investigation of samples of multiwall carbon nanotube-polymer composites by scanning electron microscopy. It is focused on multiwall carbon nanotube epoxy composite, but the strategy should be
In recent years, there has been great interest in reducing the cement content of concrete, due to the high energy and carbon dioxide footprints of cement production. There are numerous (waste) materials that can be substituted for cement in the concrete
The role of the interphase on mechanical performance of glassy polymer/single-walled carbon nanotube composites has been investigated by finite element (FE) method. The matrix and the interphase are modeled using continuum elements and the nanotube is
Michelle A. Helsel, Chiara F. Ferraris, Dale P. Bentz
The accurate measurement of the density of hydraulic cement plays an essential role in the determination of concrete mixture proportions. As more supplementary cementitious materials (SCM), such as fly ash and slag, or cement replacement materials, such as
Igor de la Varga, Jose Munoz, Dale P. Bentz, Benjamin Graybeal
Prefabricated Bridge Element and System (PBES) construction commonly relies on field-cast grout-type materials to complete the connections between precast concrete elements. The interface bond between the grout and the substrate concrete can be a key
This paper examines the pressure-dependent gas permeability as measured using a falling head gas permeameter. A series of experiments were performed on mortars with varying mixture proportions, and measurements were made with different initial applied
Alejandro Duran-Herrera, Joana K. Campos-Dimas, P Valdez, Dale P. Bentz
In this study, a copolymer composed of hollow spherical particles with an average particle size of 90 µm was evaluated as a lightweight aggregate in Portland cement-fly ash mortars to improve the thermal conductivity (k) of the composite. Mortars were
Montmorillonite clay (MMT) is frequently used to create fire resistance in Layer-by-Layer (LbL) applied coatings. This manuscript reports that switching the MMT with layered double hydroxides (LDH) produced a more effective fire resistant coating on
Kar T. Tan, Christopher C. White, Donald L. Hunston, Justin M. Gorham, Michael Imburgia, Aaron M. Forster, Vogt D. Bryan
Engineering joints consisting of polymer/inorganic interfaces are commonly exposed to less than ideal conditions during normal service; these environmental conditions present a significant challenge for maintaining the structural integrity of the interface
Edward D. McCarthy, Jae H. Kim, N. Alan Heckert, Stefan D. Leigh, Jeffrey W. Gilman, Gale A. Holmes
The mechanical integrity of a structural composite is strongly affected by the strength and toughness of the fiber-matrix interface/interphase [1], with interfacial shear strength (IFSS) being the accepted quanti-fying metric. However, the value of the
Dale P. Bentz, Scott Z. Jones, Max A. Peltz, Paul E. Stutzman
Repair mortars are being used with increasing frequency to maintain the aging US infrastructure. Durability is a key concern for such repair materials and both their volume stability and bond to the existing concrete are key attributes, the former to avoid
Emilio Hernandez-Bautista, Dale P. Bentz, Sadoth Sandoval-Torres, Prisciiano Cano Barrita
The mass and heat transport during steam curing of concrete has a bearing on both the mechanical and durability properties. Therefore, it is essential to take into account the temperature evolution and the moisture distribution to prevent premature damage
Christopher C. White, Donald L. Hunston, Kar tean Tan
In outdoor exposures used to establish durability of sealant formulations, applied strain is typically absent. It is a critical aspect of the in-service environment. This research employs two recently available techniques to examine how the presence of
Dale P. Bentz, Scott Z. Jones, Max A. Peltz, Paul E. Stutzman
Repair materials are playing an increasingly important role in the maintenance of our nations aging infrastructure. Understanding their properties and performance is critical to planning and executing appropriate repairs that will provide the requisite
Yaghoob Farnam, Sarah Dick, Andrew Wiese, Jeffrey M. Davis, Dale P. Bentz, Jason Weiss
The conventional CaCl2-H2O phase diagram is often used to describe how a calcium chloride behaves when it is used on a concrete pavement undergoing freezing and thawing damage. However, the existence of additional chemical compounds in concrete can alter
Chiao-Chi Lin, Yadong Lyu, Donald L. Hunston, Jae Hyun Kim, Kai-Tak Wan, Deborah S. Jacobs, Xiaohong Gu
The channel crack and delamination phenomena that occurred during tensile tests were utilized to study surface cracking and delamination properties of a multilayered backsheet. A model sample of commercial PPE (polyethylene terephthalate (PET)/PET/ethylene
Chiara F. Ferraris, Alex Olivas, William F. Guthrie, Blaza Toman
Rheological measurements are often performed using a rotational rheometer. In this type of rheometer, the tested fluid is sheared between two surfaces, one of which is rotating [1]. Usually, an angular velocity is imposed on the fluid (through the rotating
Chiara Villani, Catherine Lucero, Dale P. Bentz, Daniel S. Hussey, David L. Jacobson, Jason Weiss
Shrinkage Reducing Admixtures (SRAs) are increasingly being used in concrete as a method to minimize shrinkage and restrained shrinkage cracking. SRAs reduce shrinkage by decreasing the surface tension of the pore solution; however, SRAs also impact the
Catherine Lucero, Dale P. Bentz, Daniel S. Hussey, David L. Jacobson, Jason Weiss
Air entrainment is commonly added to concrete to help in reducing the potential for freeze thaw damage. It is hypothesized that the entrained air voids remain unsaturated or partially saturated long after the smaller pores fill with water. Small gel and
Christopher C. White, Donald L. Hunston, Kar T. Tan
The toughness of polymer and glass laminates or win-dow glazing, are used to protect buildings and occupants from shattered glass resulting from natural disasters (e.g., hurricanes, tornadoes, seismic events), and intentional events (e.g., robbery
Myoungsung Choi, Chiara C. Ferraris, Nicos Martys, Didier Lootens, Van Bui, Trey Hamilton
With the increasing use of pumping to place concrete, the development and refinement of the industry practice to ensure successful concrete pumping is becoming an important need for the concrete construction industry. To date, research on concrete pumping
Yaghoob Farnam, Andrew Wiese, Dale P. Bentz, Jeffrey M. Davis, Jason Weiss
MgCl2 is used in deicing applications due to its capability to depress freezing temperatures to a lower point than other salts like NaCl. The constituents of concrete (i.e., pores solution, calcium hydroxide, aluminate phases, and calcium silicate hydrate
Yaghoob Farnam, Hadi S. Esmaeeli, Dale P. Bentz, Pablo Zavattieri, Jason Weiss
In North America, some concrete pavements and sidewalks have shown severe damage during freezing. Research has been performed to better understand the cause of damage. A test method (called longitudinal guarded comparative calorimeter (LGCC)) has been
X-ray powder diffraction analysis is used in the cement industry as a direct analytical method for phase identification and quantitative analysis of clinker and cements. Quantitative methods initially relied on the development of calibration curves
Existing concrete microstructural models of particles embedded in matrix materials are only represented by regular shape particles like spheres, ellipsoids, or multi-faceted polyhedrons. However, the real particle shapes are more complex and sometimes play