Effect of interfacial transition zone on the Young's modulus of carbon nanofiber reinforced cement concrete

Zhu, Xingyi; Gao, Yuan; Dai, Ziwei; Corr, David J.; Shah, Surendra P.

doi:10.1016/j.cemconres.2018.02.014

Cited by 103 publications

(23 citation statements)

References 46 publications

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“…It is found that the calculated results are in good agreement with the experimental data. Zhu et al [12] simulates the failure process of concrete under uniaxial compression by using the finite element analysis system MFPA 2-D. The results are compared with those of physical tests, verifying the feasibility of the numerical simulation method.…”

Section: State Of the Artmentioning

confidence: 91%

Numerical simulation and analysis of the temperature effect on the fission of concrete

Liu

2019

Therm sci

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In order to further improve the crack resistance of concrete engineering, a numerical simulation method is constructed to study the effect of temperature on the fission of concrete. Based on the finite element method, the mathematical model is constructed, and the numerical calculation and image display are used to simulate and analyze the engineering problems. The temperature sensor is used to observe the whole variation law of typical temperature field, and the temperature of concrete entering and pouring is obtained. Thus, the temperature control real-time automatic acquisition system is set up. According to the temperature field and temperature stress distribution rules, the ideal temperature control curve model of concrete is proposed. Finally, the numerical calculation and experiment of the model are carried out. The results show that the maximum surface stress level decreases in varying degrees after different surface insulation measures are taken, and if the thermal insulation material's β ≤ 10 kJ/m 2 h℃, the maximum surface stress of concrete can be reduced to 0.06~0.14 MPa. In this paper, it is shown that the negative effect of the large diurnal temperature difference on concrete surface insulation can be controlled.

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Section: State Of the Artmentioning

confidence: 91%

Numerical simulation and analysis of the temperature effect on the fission of concrete

Liu

2019

Therm sci

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“…After these procedures and the image calibration, the sector in the scope of the ITZ was built (theoretical ITZ thickness located between the aggregate and paste throughout all areas). To do so, the sector previously established as the filter mask was used to establish the (theoretical) ITZ thicknesses of 10, 20, 30, 40 and 50 μm [14,27]. The image process used to achieve this was “dilation of objects”, applied to the original image of the aggregate mask and establishing the various thicknesses within the reach of the ITZ as “desired” (measured in pixels).…”

Section: Methodsmentioning

confidence: 99%

“…Those studies which have analyzed the microstructure of the RA show that there are two ITZ a) between the old natural aggregates and the old matrix of the cement and b) between the RA and the new cement matrix [11]. The ITZ is considered by many researchers to be the weak link in the concrete [12,13], in which the normal concrete fails, significantly compromising both mechanical properties and permeability; this is also characterized by being an area of high porosity [14]. This differentiated zone can form due to the “wall” effect caused by the looser packing of the cement granules against the surface of the aggregate, or because of the accumulation of free water around the surface of the aggregate [15].…”

Section: Introductionmentioning

confidence: 99%

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

Chinchillas-Chinchillas

Rosas-Casarez

Arredondo-Rea

et al. 2019

Materials

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Recycled aggregates (RA) from construction and demolition can be used in permeable concretes (PC), improving the environment. PCs have a significant porous network, their cement paste and the interaction between the paste and the RA establishing their strength. Therefore, it is important to evaluate the porosity in the interfacial transition zones. The porosity of the cement paste, the aggregate and the interfacial transitional zones (ITZ) of a PC with recycled coarse aggregates (RCA) and silica fume (SF) is measured by means of image analysis–scanning electron microscope (IA)-(SEM) and by mapping the chemical elements with an SEM-EDS (energy dispersive spectrometer) detector microanalysis linked to the SEM and, as a contrast, the mercury intrusion porosimetry technique (MIP). In the IA process, a “mask” was created for the aggregate and another for the paste, which determined the porosity percentage (for the anhydrous material and the products of hydration). The results showed that using SF caused a reduction (32%) in the cement paste porosity in comparison with the PC with RA. The use of RA in the PC led to a significant increase (190%) in the porosity at different thicknesses of ITZ compared with the reference PC. Finally, the MIP study shows that the use of SF caused a decrease in the micropores, mesopores and macropores.

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“…Many works have been done to search the properties of ITZ, such as the elastic modulus, constitutive relationship, and failure mechanism . Based on the nanotechnology, the interface between aggregate and CM is found to be around 50–60 μm.…”

Section: Simulations Of Rac Under Uniaxial Tensionmentioning

confidence: 99%

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

Wang

Peng

Kamel

2019

Structural Concrete

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In order to study the mesomechanical properties of recycled aggregate concrete (RAC) under uniaxial tension, a numerical model of RAC with two different aggregate shapes (circular and convex) and five different replacement ratios of recycled aggregate (0, 30, 50, 70, and 100%) was established. A new finite element method-base force element method (BFEM) was used to derive the element strain and the element stiffness matrix with an explicit expression without Gauss integral. The two-dimensional numerical model of the RAC was simulated to study the effect of aggregate shape, replacement ratio of recycled aggregate, aggregate distribution and interfacial transition zone (ITZ) properties on mesomechanical properties of RAC. Simulation results demonstrated that once the first crack appeared, the peak stress and peak strain were reached. The first crack appeared in old ITZ, which was located in whether the upper part or the lower part of the large-size recycled aggregate. The continuous cracks were mainly around the recycled aggregate and the aggregate concentrated area. Comparing with natural concrete, when the replacement ratio of recycled aggregate was 100%, the elastic modulus decreased by 16~25%, the peak stress decreased by 12~15%, and the peak strain changed slightly. The ITZ had a significant influence on the mechanical properties of RAC and must be considered in the analysis.

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Effect of interfacial transition zone on the Young's modulus of carbon nanofiber reinforced cement concrete

Cited by 103 publications

References 46 publications

Numerical simulation and analysis of the temperature effect on the fission of concrete

Numerical simulation and analysis of the temperature effect on the fission of concrete

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

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