Moisture profile measurements of concrete samples in vertical water flow by gamma ray transmission method

Rocha, M.; Silva, L.M. da; Appoloni, Carlos Roberto; Filho, Otávio Portezan; Lopes, Fábio; Melquiades, FÃ¡bio Luiz; Santos, Eylisson André dos; Santos, A.O. dos; Moreira, Amanda Aleixo; Pötker, W.E; Almeida, Edinei de; Tannous, C.Q; Kuramoto, Renato Yoichi Ribeiro; Cavalcante, Fábio Henrique de Moraes; Barbieri, P.F.; Caleffi, A.F; Carbonari, B.T; Carbonari, Gilberto

doi:10.1016/s0969-806x(01)00334-6

Cited by 15 publications

(7 citation statements)

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“…GRAM has commonly been used to quantify porosity and water content profiles within concrete [54,55,52]. Moreover, by making reasonable assumptions (no significant water transfer occurs by drying in the short run of an accelerated carbonation test), GRAM can also be used to assess carbonation profiles within concrete by measuring the local density increase due to carbonation (i.e., CO 2 binding) [52].…”

Section: Gamma-ray Attenuation Methods (Gram)mentioning

confidence: 99%

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Morandeau

Thiéry

Dangla

2014

Cement and Concrete Research

716

285

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The purpose of this article is to investigate the carbonation mechanism of CH and C-S-H within type-I cement-based materials in terms of kinetics, microstructure changes and water released from hydrates during carbonation. Carbonation tests were performed under accelerated conditions (10% CO 2 , 25• C and 65± 5% RH). Carbonation profiles were assessed by destructive and non-destructive methods such as phenolphthalein spray test, thermogravimetric analysis, and mercury intrusion porosimetry (destructive), as well as gamma-ray attenuation (non-destructive). Carbonation penetration was carried out at different ages from 1 to 16 weeks of CO 2 exposure on cement pastes of 0.45 and 0.6 w/c, as well as on mortar specimens (w/c = 0.50 and s/c = 2). Combining experimental results allowed us to improve the understanding of C-S-H and CH carbonation mechanism. The variation of molar volume of C-S-H during carbonation was identified and a quantification of the amount of water released during CH and C-S-H carbonation was performed.

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Section: Gamma-ray Attenuation Methods (Gram)mentioning

confidence: 99%

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Morandeau

Thiéry

Dangla

2014

Cement and Concrete Research

716

285

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“…Gammadensimetry is a non-destructive method used to determine the density or moisture content of civil engineering materials (Da Rocha et al, 2001;Villain and Thierry, 2006;Ferraz and Aguiar, 1985). This technique is based on the absorption of gamma rays emitted by a radioactive source (in our case Cesium Cs 137 ) and follows Lambert's law.…”

Section: -Gammadensimetry Methodsmentioning

confidence: 99%

Numerical and experimental approaches to characterize the mass transfer process in wood elements

et al. 2017

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The scope of this paper is an experimental characterization of diffusion parameters for wood material. Based on a nonlinear mass transfer algorithm, the present study focuses on the need to capture experimental moisture profiles in the sample, along with its evolution in weighting during both the desorption and adsorption phases, especially when the moisture content of the samples is far from the equilibrium state inducing a great gradient between heart and exchange surfaces of specimen. These moisture profiles are derived by means of a gammadensimetry laboratory method based on the water adsorption of gamma rays. The determination of the diffusion parameters obtained through optimizing a simulation by means of implementing the mass transfer kinetics into a finite difference method. Both the diffusion coefficient and convective exchange coefficient are deduced by considering a Nelder-Mead simplex inversion method. This work highlights the efficiency of the approach dedicated to uncoupling nonlinear diffusion in the cross-sections from boundary conditions in terms of convective

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“…[17,49,58,[64][65][66] X-ray absorption [67][68][69] and scanning neutron radiography [70] are based on the same principle (weakening of radiation passing through a material) but can offer a higher spatial resolution (in the range of 1 mm, against several mm for the γ sources commonly used).…”

Section: Internal Rh By Rh-sensormentioning

confidence: 99%

Aging and durability of concrete in lab and in field conditions – pore structure and moisture content gradients between inner and surface zones in RC structural elements

Baroghel-Bouny¹,

Thiéry²,

Dierkens³

et al. 2016

Journal of Sustainable Cement-Based Materials

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To cite this article: V. Baroghel-Bouny, M. Thiery, M. Dierkens & X. Wang (2016): Aging and durability of concrete in lab and in field conditions -pore structure and moisture content gradients between inner and surface zones in RC structural elements, Journal of Sustainable Cement-Based Materials, In real structures, gradients between inner and surface zones, which depend on the mix-design, as well as on curing and environmental conditions, are critical issues for durability, in particular when the mixture incorporates supplementary cementitious material (e.g. fly ash (FA)). This paper deals with pore structure and moisture content gradients, investigated not only on concrete samples in lab conditions, but also on reinforced concrete (RC) structural elements exposed for several years to three different outdoor environments (temperate climate, tidal zone in marine environment, as well as road and cold environment) and on full-scale structures (bridges). The experimental study was launched a lot of years ago within the framework of the large-scale and long-term "BHP 2000" French national project. The various mixtures studied (28-day cylinder compressive strengths ranging from 20 to 130 MPa) include high-performance concretes (HPCs) with or without silica fume (SF), as well as normal strength FA concretes. MIP pore size distributions obtained on the RC structural elements have been compared to lab results. In addition, in order to investigate the long-term drying(-wetting) behavior of the various types of materials studied here, water vapor desorption isotherms, internal relative humidity (RH), and degree of saturation profiles have been measured, respectively, by the saturated salt solution method, RH sensors, and gamma-ray attenuation on lab samples or on cores extracted from the elements and bridges at various times. The data have been analyzed as a function of the exposure conditions and of the mix-parameters. For example, the impact of early age external drying, carbonation, as well as freezing and thawing cycles in the presence of deicing salts has been highlighted on the field data. In addition, good performance of SF-HPCs and mature FA-concretes has been pointed out in the outdoor conditions considered.

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Moisture profile measurements of concrete samples in vertical water flow by gamma ray transmission method

Cited by 15 publications

References 0 publications

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Numerical and experimental approaches to characterize the mass transfer process in wood elements

Aging and durability of concrete in lab and in field conditions – pore structure and moisture content gradients between inner and surface zones in RC structural elements

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