scholarly journals Experimental and Mesoscopic Lattice Numerical Investigation of Increase of Chloride Diffusivity Coefficient during Uniaxial Loading Model

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Son Bui Truong ◽  
Pham DUC THO
Keyword(s):  
Diffusion Coefficient ◽  
Axial Loading ◽  
Damage Variable ◽  
Test Method ◽  
Chloride Diffusion ◽  
Diffusivity Coefficient ◽  
Chloride Diffusion Coefficient ◽  
Loading Test ◽  
Chloride Diffusivity ◽  
Coefficient Versus

This paper presents experimental and simulation results of the change in the chloride diffusion coefficient of concrete C40 (f’c=40 MPa) during axial loading. Test Method for Electrical Indication was used to measure the chloride diffusivity of the concrete sample during the axial loading. A mesoscopic lattice model is proposed to describe the variation of chloride diffusion coefficient versus damage variable. In such a model, the domain of material is discretized randomly by using Voronoi tessellation for the transport element and Delaunay triangulation for a mechanical element. At the mesoscale, the concrete is constituted by three phases: aggregate, cement paste and ITZ, in which aggregate is assumed to be elastic while cement matrix and ITZ are represented by a damage model with softening. The experimental and numerical results show that in the first stage, without crack (s < 40%smax), the chloride diffusion coefficient remains almost constant, however in the crack initiation and propagation stage (s = 60-80%smax) chloride diffusion coefficient increases significantly. An empirical power model is also proposed to describe the increase of the chloride diffusion coefficient versus stress level and damage variable.

Testing for the Influence of the Degree of Water Saturation of Concrete upon Chloride Diffusivity

2013 ◽  
Vol 405-408 ◽  
pp. 2639-2643
Author(s):  
Van Tuan Le ◽  
Yong Lai Zheng ◽  
Shu Xin Deng
Keyword(s):  
Diffusion Coefficient ◽  
Water Saturation ◽  
Chloride Ion ◽  
Test Method ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Ion Diffusion ◽  
Chloride Diffusivity ◽  
Water Saturated ◽  
The Impact

In order to estimate the impact of the degree of water saturation of concrete to chloride ion diffusion coefficient, the experimental setup allows to measure chloride diffusion coefficient through nonsaturated concrete specimens with controlled degree of water saturated. The different degrees of water saturation of concrete specimens were obtained, by using saturated solutions of NaCl and KCl controlling the relative humidity, then applied Rapid Cloride Permeability Test method to measure the cloride diffusion coefficient. The test results show that chloride diffusion coefficient depends strongly on the degree of water saturation of concrete. Beside, this relationship shows the non-linear relationship, in which, chloride diffusion coefficient reachs the maximum value in fully saturated concrete specimens.

Study on Permeability of Concrete under Sustaining Tension

2010 ◽  
Vol 163-167 ◽  
pp. 3306-3310
Author(s):  
Li Guo Ma ◽  
Yun Sheng Zhang ◽  
Lu Guang Song
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Experimental Method ◽  
Experimental Device ◽  
Chloride Diffusion ◽  
Tension Stress ◽  
Diffusivity Coefficient ◽  
Chloride Diffusion Coefficient ◽  
Chloride Diffusivity ◽  
Chloride Migration

An experimental device which provided uniaxial sustaining tension stress to concrete was especially designed with pressed spring. The accelerated, steady state chloride migration experimental method was used to test the permeability of concrete under tension resulting from designed device. Concrete with two mixture proportions was tested to get chloride diffusion coefficient under different tension stress. Mathematics models were built to show the change of chloride diffusivity coefficient of concrete under tension.

Experimental Study on the Chloride Diffusivity of Recycled Aggregate Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1404-1408
Author(s):  
He Ying Qin ◽  
Yan Lin Zhao ◽  
Bo Guang Luo ◽  
Yi Hu Chen
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Silica Fume ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Chloride Diffusion ◽  
Partial Replacement ◽  
Chloride Diffusion Coefficient ◽  
Aggregate Concrete ◽  
Chloride Diffusivity

The study presented herein has been carried out in order to investigate the chloride diffusivity of recycled aggregate concrete (RAC). Meanwhile, the effect of the binder type, involving cement replacement materials such as, fly ash, slag and silica fume on the chloride diffusivity has also been investigated. For this purpose, RAC and concrete containing the different type of binders with w/b ratios of 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60 were used. As a result, the chloride diffusion coefficient of RAC is higher than that of natural concrete and the partial replacement of cement with fly ash, slag and silica fume is effective in decrease in the chloride diffusion coefficient, measured by a rapid chloride conductivity test.

scholarly journals Sustainability of Reinforced Concrete Beams with/without BF Influenced by Cracking Capacity and Chloride Diffusion

2020 ◽  
Vol 12 (3) ◽  
pp. 1054 ◽  
Author(s):  
Yurong Zhang ◽  
Chaojun Mao ◽  
Jiandong Wang ◽  
Yanhong Gao ◽  
Junzhi Zhang
Keyword(s):  
Diffusion Coefficient ◽  
Reinforced Concrete ◽  
Basalt Fiber ◽  
Load Level ◽  
Reinforced Concrete Beams ◽  
Chloride Diffusion ◽  
Rc Beam ◽  
Chloride Diffusion Coefficient ◽  
Coupling Interaction ◽  
Chloride Diffusivity

Concrete’s production causes pronounced environmental impacts. It is confirmed that adding basalt fiber (BF) into concrete can improve the mechanical properties and reduce the chloride diffusion coefficient of concrete. Moreover, research on the environmental impact of BF and its application in concrete has gradually emerged in recent years. However, there is little research on the chloride diffusivity of concrete structures with BF under the coupling interaction of external loads and chloride action. Therefore, at first, six beams were cast to obtain the depth-dependent chloride diffusivity of concrete under the coupling interaction of chloride penetration and 50% and 80% of the cracking capacity. Then, a functional unit (FU) combining durability, cracking capacity and volume was proposed to evaluate the sustainability of the concrete structure. In addition, three extra FUs (volume, considering volume and cracking capacity simultaneously and considering volume, cracking capacity and durability simultaneously) were also proposed and compared with the first FU. Results indicate that, regardless of the applied load level, the average chloride diffusion coefficient of a reinforced concrete (RC) beam with BF is larger than that of an ordinary RC beam. Moreover, the sorting of life cycle assessment (LCA) results will vary significantly with the different preset functional units. When taking the cracking capacity into consideration, adding BF into concrete is a suitable solution to improve the sustainability of RC beams.

Damage and Chloride Penetration of Cement Mortar under Conventional Triaxial Compression

2011 ◽  
Vol 71-78 ◽  
pp. 744-747
Author(s):  
Zu Quan Jin ◽  
Qiu Yi Li ◽  
Chuan Li ◽  
Tie Jun Zhao
Keyword(s):  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Triaxial Compression ◽  
Axial Loading ◽  
Chloride Content ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Axial Deformation ◽  
Free Chloride ◽  
Conventional Triaxial Compression

In this paper, the influence of conventional triaxial compression on damage and chloride ion penetration of cement mortar are investigated. Conventional triaxial compression experiment was carried out with confining loading of 10Mpa. And the stress-strain curve was measured when axial stress was 50%, 80% and 100% of peak axial loading, and 80% axial loading post-maximum. Then the damaged cement mortars was stored in Qingdao sea water for 30 days, and the free chloride content as well as chloride diffusion coefficient of damaged mortars were quantitatively determined. The experimental results show that the cement mortar is compacted in the end, and shear damaged in the middle under conventional triaxial compression. Compared to cement mortar under uniaxial compression, its compressive strength and axial deformation increases by 1.94 times and 5.6 times when cement mortar under conventional triaxial compression. When the axial stress is less than 48% of peak axial loading, and the axial deformation is less than 0.63mm, the mortar is compacted and its relative dynamic elastic modulus increases with raising axial loading and deformation. The free chloride content in the pressure-bearing side is higher than that in the bottom side. And the free chloride content in the interior of mortar increases with raising axial loading. The chloride diffusion coefficient and axial loading are related in quadratic function. When the axial deformation of mortar is higher than 0.72mm and 1.57mm, the chloride diffusion coefficient of non-load mortar, is less than that of loaded mortar in the pressure-bearing side, and in the bottom side, respectively.

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