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Jonathan W. Martin, Xiaohong Gu, Tinh Nguyen, Joannie W. Chin
NIST has initiated a research program for improving the quality of the data input for making economic sustainability assessments of polymeric infrastructure materials through improvements in the measurement science for this data. Sustainability assessments
The water absorption behavior of cement pastes (w/c = 0.30) containing varying concentrations (i.e., 0 %, 0.2 % and 5 %) of a shrinkage reducing admixture (SRA) was measured. Moisture ingress was monitored using x-ray absorption. A decrease in both the
The Outer Shell of the jacket and pants of the firefighter s protective clothing is constructed of a fabric that is commonly a blend of polyaramid, polybenzimidazole, and/or poly(melamine-formaldehyde) fibers. The Outer Shell contributes to the thermal and
Donald L. Hunston, Kar T. Tan, Bryan D. Vogt, Sushil K. Satija, Cyril Clerici, David E. White
The ability of water to dramatically weaken many types of adhesive bonds has been widely studied. One surprising result is the existence of a critical moisture level in the bond. Above this level the strength drops to very low values. Numerous studies have
Kar T. Tan, Christopher C. White, Donald L. Hunston, Kristen L. Steffens, Hatlee Timothy, Kristen Hamilton, Vogt D. Bryan
Adhesion loss due to moisture is a fundamental problem in a large diversity of industries ranging from microelectronics and automotive to aerospace. This study investigates the durability of model adhesive joints consisting of a homologous series of poly(n
There are many improvements needed in concrete, especially for use in renewal and expansion of the world's infrastructure, e.g. increased durability, decreased brittleness and increased tensile strength, and use of non-traditional materials like fly ash
Ryan Henkensiefken, Peter Briatka, Dale P. Bentz, Tommy Nantung, Jason Weiss
The incorporation of pre-wetted lightweight aggregates (LWA) has been used to reduce the shrinkage cracking associated with self-desiccation in the hardened state. Little research however exists which shows the influence of internal curing on the formation
Jeffrey W. Bullard, Edith Enjolras, William L. George, Steven G. Satterfield, Judith E. Terrill
A recently described stochastic reaction-transport model on three-dimensional lattices is parallelized and is used to simulate the time-dependent structural and chemical evolution in multicomponent reactive systems. The model, called HydratiCA, uses
Min-Hong Zhang, Chiara C. Ferraris, Huaning Zhu, Vincent Picandet, Max A. Peltz, Paul E. Stutzman, Daniel De Kee
Slump has often been correlated with the yield stress of concrete as defined by the Bingham model. The discussion is still open as to what the yield stress value actually is and how to measure the yield stress of a suspension in general and for a
A new approach for increasing the service life of concrete structures is evaluated in a series of mortar specimens. The new approach consists of employing nanoscale viscosity modifiers to increase the viscosity of the concrete pore solution and
The mineralogical and microstructural changes that occur in cementitious systems during hydration are summarized. The discussion concentrates on changes that may occur in iso-thermal systems that do not interact with the environment. The discussion
Stephanie S. Watson, Tarek Marray, Yongyan Pang, Li Piin Sung
Metal oxide fillers, such as titanium dioxide (TiO2) are commonly used in building and construction applications and are added to increase the opacity and/or to improve the mechanics of a coating. However, their photoreactivity can contribute to
Andrew J. Allen, Jeffrey J. Thomas, Hamlin M. Jennings
Microstructure development and the kinetics of hydration of pure tricalcium silicate (C3S) and CaCl2-accelerated C3S pastes were investigated by performing isothermal calorimetry and in situ small-angle neutron scattering (SANS) measurements on parallel
Kenneth A. Snyder, Paul E. Stutzman, Jacob Philip, David W. Esh
The hydration products of varying proportions of portland cement, fly ash, ground granulated blast furnace slag, and silica fume in blended systems were identified and quantified. The proportion of portland cement varied from 100 % down to 10 %. The
The purpose of this study is to develop relevant metrology to measure the appropriate structure-property relationship at a proper length scale to understand the interplay between nanoparticle and polymeric matrix. In this paper, we present the preliminary
Jeffrey W. Bullard, Paul E. Stutzman, Luis M. Ordonez-Belloc, Edward J. Garboczi, Dale P. Bentz
The NIST-Industry Virtual Cement and Concrete Testing Laboratory (VCCTL) Consortium has developed an integrated software package for performing simulations of a number of engineering test measurements, including isothermal calorimetry, adiabatic
Dale P. Bentz, Edward J. Garboczi, Nicos Martys, Kenneth A. Snyder, W. S. Guthrie, Konstantinos Kyritsis, Narayanan Neithalath
The transport properties of concrete are critical to its field performance. Commonly encountered degradation mechanisms are dependent on ionic diffusivity, sorptivity, and permeability. In this paper, virtual testing of two of these concrete transport
Ryan Henkensiefken, Javier Castro, Dale P. Bentz, Tommy Nantung, Jason Weiss
The increased propensity for shrinkage cracking in low w/c concrete has spawned the development of new technologies that can reduce the risk of early-age cracking. One of these is internal curing. Internal curing uses saturated lightweight aggregate to
Nicos Martys, William L. George, Didier Lootens, Pascal Hebraud
Spatio-temporal correlations in start-up flows of attractive colloids are explored by numerical simulations. The suspension is first allowed to flocculate during a time tw, then the stress necessary to induce its flow is computed. Whereas at low volume
Organofunctionalized montmorillonite clays (MM) have been prepared with ammonium cations having a distribution of alkyl chain lengths. Relative to clays treated with alkylammonium cations having no distribution of chain lengths, the ultimate tensile stress
The influence of water-to-cement mass ratio (w/c) on early-age properties of cement-based materials is investigated using a variety of experimental techniques. Properties that are critical to the early-age performance of these materials are tested
Ryan Henkensiefken, Javier Castro, Haejin Kim, Dale P. Bentz, Jason Weiss
Internal curing (IC) provides a set of water reservoirs within the concrete to prevent self-desiccation and promote hydration. While early research in this area focused on reductions in early-age deformation and cracking, recent efforts have demonstrated
Li Piin Sung, Dongmei Zhe, Aaron M. Forster, Peter Krommenhoek, Nancy J. Lin, Sheng Lin-Gibson
Investigation on the effect of nano-silica on the effect of nano-silica on the surface morphology and mechanical properties has been carried out on two-dimensional (2D) gradient polymer-silica composite samples varied in chemical composition (e.g., filler
Ryan Henkensiefken, Dale P. Bentz, Tommy Nantung, Jason Weiss
Increased occurrences of early-age shrinkage cracking in low water to cement ratio (w/c) concrete have spawned innovative developments in mixture design that reduce the risk of cracking. One such development is internal curing, which utilizes the inclusion