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Patent
Giatec Scientific | Date: 2017-03-22

Concrete can be one of the most durable building materials and structures made of concrete can have a long service life. Consumption is projected to reach approximately 40 billion tons in 2017. Despite this the testing of concrete at all stages of its life cycle is still in its early stages although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Embodiments of the invention provide concrete suppliers, construction companies, regulators, architects, and others with rapid testing and performance data regarding the cure, performance, corrosion of concrete at different points in its life cycle based upon a simple electrical tests that remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment. Wireless sensors can be embedded from initial loading through post- cure into service life.


Nguyen D.-T.,University of Ottawa | Alizadeh R.,Giatec Scientific | Beaudoin J.J.,National Research Council Canada | Raki L.,National Research Council Canada
Materials and Structures/Materiaux et Constructions | Year: 2013

Microindentation creep measurements were obtained on compacted specimens of several secondary hydrated cement phases in equilibrium with water vapor at 11%RH. Values of creep modulus, indentation modulus and indentation hardness for calcium hydroxide, ettringite, gypsum and calcium carbonate are reported. The porosity dependence of these parameters was established and the significance of porosity on the time-dependent deformation of these materials was discussed. In addition the microindentation creep behavior of pure C-S-H and C3S paste hydrated 32 years was determined. The discussion focuses on the relative importance of the contribution of the secondary phases in hydrated cement-based materials to creep with respect to the more 'active' C-S-H phase. © 2012 RILEM.


Khoshnazar R.,National Research Council Canada | Beaudoin J.J.,National Research Council Canada | Raki L.,National Research Council Canada | Alizadeh R.,Giatec Scientific
Materials and Structures/Materiaux et Constructions | Year: 2016

The influence of nitrobenzoic acid on the nanostructure of calcium-silicate-hydrate (C–S–H) systems has been recently investigated by the authors. This study focuses on the assessment of durability and mechanical performance of the C–S–H/nitrobenzoic acid composite systems. In this context different nitrobenzoic acid isomers in various concentrations were studied. The C–S–H-based preparations were compacted into porous bodies. Their dimensional stability and the leaching of calcium ions in aqueous salt solutions containing Mg2+, Li+, Cl− or SO4 2− ions were evaluated. The resistance of the compacted samples to the diffusion of isopropyl alcohol was also obtained by the mass-change measurements. The microindentation technique was used to measure the creep modulus and the hardness of the samples. Evidence was obtained that nitrobenzoic acid has the potential to significantly improve the durability and mechanical properties of the C–S–H systems. This improvement, however, only occurred in the systems with the lower concentration of nitrobenzoic acid. The systems with higher concentration of nitrobenzoic acid had reduced durability and mechanical performance due to the limited interaction of the organic and inorganic phases in these systems. © 2016 RILEM


Pourbeik P.,National Research Council Canada | Beaudoin J.J.,National Research Council Canada | Alizadeh R.,Giatec Scientific | Raki L.,National Research Council Canada
Advances in Cement Research | Year: 2015

Dynamic mechanical thermal analysis (DMTA) measurements for layered calcium silicate systems (1.4 nm tobermorite, jennite, synthetic calcium-silicate-hydrate and hydrated Portland cement paste) are reported. Elastic modulus results were obtained for samples initially conditioned to 11% relative humidity (RH) and dried during the DMTA test and for samples subjected to prolonged vacuum and thermal drying prior to a DMTA test. Decreases in elastic modulus relative to the 11% RH starting condition typically observed during a DMTA test were recovered subsequent to the prolonged thermal treatment. A possible 'regeneration' mechanism for the elastic modulus is discussed. The 'regeneration' occurs for all the calcium silicate systems studied. The results are consistent with the notions expressed for nanostructural models of calcium-silicate-hydrate in cement paste that comprise structural units based on 1.4 nm tobermorite and jennite.


Pourbeik P.,National Research Council Canada | Beaudoin J.J.,National Research Council Canada | Alizadeh R.,Giatec Scientific | Raki L.,National Research Council Canada
Materials and Structures/Materiaux et Constructions | Year: 2016

Microindentation creep and dynamic mechanical thermo-analysis measurements were carried out on compacted specimens of cement paste prepared at water/cement ratios of 1.00, 0.50 and 0.40 and hydrated for 45 years. Similar data was obtained for pastes prepared at w/c = 0.40 and hydrated only 2 months. Creep modulus–mass-loss curves were plotted for all the systems studied. These curves were used to emphasize salient differences between all the paste systems. The influence of degree of hydration, volume concentration of C–S–H, capillary porosity, C–S–H chain-length and the restraining effect of the unhydrated cement particles on creep are parameters that are used to provide a possible explanation for the observation that the creep of the old pastes is higher than creep of the young pastes. The structural role of water in the creep process at various stages of equilibrium drying from the 11 % RH condition is discussed. © 2015, RILEM.


Nguyen D.-T.,University of Ottawa | Alizadeh R.,Giatec Scientific | Beaudoin J.J.,National Research Council Canada | Pourbeik P.,University of Ottawa | Raki L.,National Research Council Canada
Cement and Concrete Composites | Year: 2014

Microindentation creep results for monophasic synthetic C-S-H (C/S = 0.6-1.5), 1.4 nm tobermorite, jennite and calcium hydroxide at 11%RH are reported. Creep results for well hydrated cement paste and C3S 'composite' systems are also described. The significance of the co-linear behavior of creep modulus functions of indentation modulus and indentation hardness for C-S-H obtained by microindentation and nanoindentation methods is discussed. The porosity dependence of creep modulus and the general equivalence of density values determined by helium pycnometry and by calculations employing unit cell dimensions (obtained using X-ray crystallography techniques) are also discussed in terms of postulates for the existence of two types of C-S-H. Comment on the compatibility of the creep modulus data for 1.4 nm tobermorite and jennite with models of C-S-H present in cement paste is provided. © 2013 Elsevier Ltd. All rights reserved.


Trademark
Giatec Scientific | Date: 2017-01-19

Concrete testing devices, sensors, software, and technologies for measuring the non-destructive properties of concrete. Providing corrosion evaluation, quality control, testing and assessment of infrastructure, namely buildings, bridges, roads, paths, tunnels, walls, floors, pre-fabricated building panels, and prefabricated concrete structures during fabrication and use; providing engineering and technological consulting services, namely, advising on concrete mixture proportioning for specific applications, durability design of concrete materials, corrosion detection, and detailed condition assessment of concrete structures; development of concrete testing technologies in the field of construction industry.


Trademark
Giatec Scientific | Date: 2016-09-27

Monitoring devices, namely, sensors such as for humidity, pressure, pH, vibration, and temperature with electrical assessment such as resistance, current, potential, and impedance; self-contained monitoring devices, namely, sensors such as for humidity, pressure, pH, vibration, and temperature with electrical assessment such as resistance, current, potential, and impedance; downloadable software in the field of electrical and environmental measurements and characterisation; downloadable software for configuring, reading, and interfacing to monitoring devices, namely, sensors such as for humidity, pressure, pH, vibration, and temperature with electrical assessment such as resistance, current, potential, and impedance. Providing non-downloadable software in the field of electrical and environmental measurements and characterization.


Trademark
Giatec Scientific | Date: 2017-01-19

Hand-held devices for corrosion evaluation of reinforced concrete structures; hand-held devices for measuring corrosion rate of concrete reinforcement bar, electrical resistivity of concrete, corrosion potential of concrete reinforcement bar, and ambient temperature and relative humidity.


Patent
Giatec Scientific | Date: 2014-01-30

Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified. Beneficially a method of determining the state of a rebar without electrical contact is taught.

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