Pore structure of hardened portland cement pastes and its influence on properties

Beaudoin, J.J.; Feldman, R.F.; Tumidajski, Peter J.

doi:10.1016/1065-7355(94)90028-0

Cited by 80 publications

(28 citation statements)

References 49 publications

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“…Portland cement-based concrete is a multicomponent, microporous, microstructure-sensitive construction material (Beaudoin et al, 1994). The pores in concrete are randomly sized, arranged, and connected, and the movement of water and ions through those tortuous channels is governed by permeation, absorption, and diffusion mechanisms (Samaha and Hover, 1992).…”

Section: Introductionmentioning

confidence: 99%

Effect of moisture content on concrete resistivity measurement

Su¹,

Yang²,

Wu³

et al. 2002

Journal of the Chinese Institute of Engineers

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The resistivity of concrete was investigated in this study by employing the Wenner technique. Cylindrical specimens with various water/cement ratios (w/c=0.45, 0.55, and 0.65) were cast and tested. In order to study the effect of moisture content on concrete resistivity, the resistivity and weight were measured for air-dried specimens and oven-dried specimens. Test results show that the resistivity decreases with an increase in w/c ratio, but for the saturated concrete specimens with high w/c ratios (w/c>0.55) the resistivity difference is small. For specimens after 8-hours of air drying, the water loss ratio was about 0.7% and the normalized resistivity increased from 5% to 10% in comparison with the saturated concrete specimens. When the water loss ratio was higher than 3%, the concrete resistivity abruptly increased for all mixes. Therefore, the effect of moisture content on concrete resistivity measurement should be considered in durability evaluation.

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Section: Introductionmentioning

confidence: 99%

Effect of moisture content on concrete resistivity measurement

Su¹,

Yang²,

Wu³

et al. 2002

Journal of the Chinese Institute of Engineers

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“…For the phase composition resulting from the hydration reaction, an experiment-based hydration reaction formula was proposed quite some time ago (Osbaeck 1992), and more recently, the development of data for thermodynamic equilibrium calculations has been progressing, leading to more sophisticated prediction methods (Lothenbach and Winnefeld 2006;Blanc et al 2010;Nonat 2004). With regard to the pore structure in cement paste, although a sufficient scientific foundation is not yet in place due to the complexity of C-S-H behavior, various engineering models have been proposed, and there are many methods to predict properties based thereon (Jons and Osbaeck 1982;Beaudoin 1994;Shimomura and Maekawa 1997).…”

Section: Introductionmentioning

confidence: 99%

Cement Reaction and Resultant Physical Properties of Cement Paste

Maruyama

Igarashi

2014

ACT

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The body of data about the reaction kinetics of cement has greatly grown in recent years, and in terms of techniques for the prediction of the resulting hydrate formation phases, databases contributing to thermodynamic equilibrium calculations have been developed and are growing increasingly sophisticated. On the other hand, though many studies on cement aim to contribute to concrete engineering and numerical model researchers have pointed out the necessity of shedding light on the relationship between the microstructures generated by hydration and physical properties, such data remains scarce. This study investigated Portland cements using two commonly used water-cement ratios and three types of mineral compositions in the material age range of up to one year. The phase composition in relation to cement hydration was determined by X-ray powder diffraction and Rietveld analysis. In terms of physical properties, compressive strength and Young's modulus were measured through loading tests, and Young's modulus and Poisson's ratio were also obtained from the ultrasonic pulse propagation velocity of longitudinal and transverse waves. Further, water vapor adsorption tests to shed light on moisture behavior were conducted, yielding the BET specific surface area. Thermal conductivity, an important determinant of thermal behavior, was measured using the transient hot wire method. On the premise of the application of these physical properties to numerical calculations, their correlation with the information obtained from the phase composition was considered, leading to the proposal of simple and relatively high-accuracy empirical formulas. Further, background information about raising the correlation of these empirical formulas was also discussed.

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“…It includes porosity, pore size distribution and surface area. Pore structure at both micro and meso levels is an important characteristic, which determines macro properties of concrete such as strength [8][9][10][11][12][13][14], elasticity, shrinkage [15], durability [16][17][18][19] and, etc. Cement paste, mortar, and concrete are all porous materials.…”

Section: Porous Structure For Cementmentioning

confidence: 99%