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Full-Text Articles in Engineering
Chloride-Binding Isotherms In Concrete Submitted To Non-Steady-State Diffusion-Migration Model, Wen-Hu Tsao, Ming-Te Liang, Ta-Peng Chang
Chloride-Binding Isotherms In Concrete Submitted To Non-Steady-State Diffusion-Migration Model, Wen-Hu Tsao, Ming-Te Liang, Ta-Peng Chang
Journal of Marine Science and Technology
We propose a mathematical non-steady-state, time/depth dependent diffusion-migration model based on the modified Fick’s second law of diffusion. It considers the effects of different chloride binding mechanisms for the transport process of chloride ions diffused in a porous concrete on the variation of its chloride profile. Four different chloride-binding isotherms, i.e., no binding, linear binding, Langmuir binding and Freundlich binding, together with the time/depth dependent chloride diffusivities are investigated. Results of this study show that the variations of amounts of available free chloride ions in the solution of saturated concrete resulting from different chloride-binding isotherms have significant effects on the …
Carbonation Resistance Of Concrete With Mortar Coating, Wen-Hu Tsao, Ming-Te Liang, Nai-Ming Huang, Ke-Hung Liao
Carbonation Resistance Of Concrete With Mortar Coating, Wen-Hu Tsao, Ming-Te Liang, Nai-Ming Huang, Ke-Hung Liao
Journal of Marine Science and Technology
The principal purpose of this paper was theoretically to study the carbonation resistance of a semi-infinite medium which concrete has a mortar coating having diffusion properties different from those of the rest of the medium. The analytical solution of a semi-infinite composite medium was used to predict the time required for subsidence due to concrete with mortar coating. The inaccurate analytical solution was published in previous books. Thus, the analytical solution of a semi-infinite composite medium is re-derived in this article. The governing equations without initial and boundary conditions in the previous books are also pointed out. In order to …
Evaluation Of Penetration Depth And Protective Effectiveness Of Concrete-Penetrating Sealer Materials, Sung-Ching Chen, Ran Huang, Hui-Mi Hsu, Si-Yu Zou, Li-Wei Teng
Evaluation Of Penetration Depth And Protective Effectiveness Of Concrete-Penetrating Sealer Materials, Sung-Ching Chen, Ran Huang, Hui-Mi Hsu, Si-Yu Zou, Li-Wei Teng
Journal of Marine Science and Technology
Crystal penetrating sealer materials (PSMs) are commonly used on the surface of concrete to protect the surface from damage and thereby extend its service life. Such materials penetrate into existing pores or cracks and form crystals, which block potential paths through which unknown materials could enter and degrade the concrete. In this study, the constituent compounds of a PSM were divided into seven categories, labeled CAT I to CAT VII, and five discrete particle size fractions corresponding to sieve Nos. 30, 50, 100, 200, and 200 were considered. Energy dispersive spectrometry revealed that the constituent elements of the PSM were …
Corrosion Of Rebar Under Carbonation And Salt Environment, Wei-Chung Yeih, Jiang-Jhy Chang, Yu-Ping Huang, Ran Huang
Corrosion Of Rebar Under Carbonation And Salt Environment, Wei-Chung Yeih, Jiang-Jhy Chang, Yu-Ping Huang, Ran Huang
Journal of Marine Science and Technology
In this study, the behavior of reinforced concrete under carbonation and in a salt environment was investigated. Three types of cements- Type I cement, Type II cement and highalumina cement (HAC) - were used to study the influence of cement on reinforced concrete behavior. To simulate chloridecontaminated concrete, 1% NaCl (by cement weight) was added to some groups of specimens. Results revealed that the carbonation released chloride ions from Friedel's salt, which increased the chloride content near the carbonation front. The carbonation rate of HAC concrete was higher than that of Type I and Type II cement concrete. The corrosion …
Analytical Model Of Ultrasonic Pulse Velocity Of Waste Lcd Glass Concrete, Chien-Chih Wang, Her-Yung Wang, Shyh-Haur Chen, Chi Huang
Analytical Model Of Ultrasonic Pulse Velocity Of Waste Lcd Glass Concrete, Chien-Chih Wang, Her-Yung Wang, Shyh-Haur Chen, Chi Huang
Journal of Marine Science and Technology
The purpose of this study is to establish a prediction model for the ultrasonic pulse velocity (UPV) of waste LCD glass concrete and then analyze the results obtained from a series of laboratory tests. The power function is used to perform the nonlinear-multivariate regression analysis of the UPV prediction model, with parameters such as water-binder ratio (w/b), curing age (t) and waste glass content (G). According to the relative regression analysis, the UPV prediction model is developed. The calculated results are in accord with the laboratory-measured data, which are the concrete UPV of various mix proportions. The regression analysis results …
Effect Of Mortar Coating On Concrete Carbonation, Wen-Hu Tsao, Ming-Te Liang, Jiang-Jhy Chang, Nai-Ming Huang
Effect Of Mortar Coating On Concrete Carbonation, Wen-Hu Tsao, Ming-Te Liang, Jiang-Jhy Chang, Nai-Ming Huang
Journal of Marine Science and Technology
The mechanism of the effect of mortar coating on carbonation of concrete is investigated. Theoretical methods of Fick's first and second laws of linear diffusion are used to calculate the carbonation depth of concrete without and with mortar coating, respectively. Theoretical analyses are also done to obtain the carbonation retard coefficients of mortar coating on concrete with surface coatings. A great deal of well organized experimental tests are carried out to verify the values of calculation. The results of present study indicate that the suitable mortar coating on concrete can effectively delay carbonation of concrete. The carbonation depth is inversely …
Sensitivity Analysis Of Time/Depth Dependent Chloride Diffusion Coefficient In Concrete, Yung-Ming Sun, Ta-Peng Chang, Ming-Te Liang
Sensitivity Analysis Of Time/Depth Dependent Chloride Diffusion Coefficient In Concrete, Yung-Ming Sun, Ta-Peng Chang, Ming-Te Liang
Journal of Marine Science and Technology
This paper presents the results for a sensitivity analysis of the time/depth dependent chloride diffusion model in concrete using differential analysis techniques. Four governing prameters of the model are taken to determine the sensitivity of the chloride diffusion coefficient: the time of exposure, inspecting depth, surface chloride concentration, and chloride concetration at the inspecting point. The results of this sensitivity analysis are discussed in detail, including variations in the diffusion coefficient according to the four parameters and the implications for durability design of concrete structures.
Biodeterioration Of Coastal Concrete Structures By Macro Algae - Ulva Fasciata, Stri Hari Babu Jayakumar, Rama Saravanane, Thirumalai Sundararajan
Biodeterioration Of Coastal Concrete Structures By Macro Algae - Ulva Fasciata, Stri Hari Babu Jayakumar, Rama Saravanane, Thirumalai Sundararajan
Journal of Marine Science and Technology
Puducherry is a coastal region in India where the growth of Ulva fasciata (Delile) is very abundant on all marine structures. Though the detrimental effect of this macro algae U. fasciata is a secondary one, its effect has to be investigated. To know its effect, the basic mechanism by which U. fasciata deteriorates concrete structures has been highlighted. To ascertain its detrimental effect on coastal concrete structures, M20 grade concrete cubes were casted and immersed in the coastal area where there is abundant growth of U. fasciata. In addition laboratory simulation has been carried out. Concrete samples collected from the …
Penetration Lag Of Chloride Diffusion Through Concrete Plate Based On Advancing Model, Chih-Hsing Wang, Cho-Liang Tsai, Ching-Chang Lin
Penetration Lag Of Chloride Diffusion Through Concrete Plate Based On Advancing Model, Chih-Hsing Wang, Cho-Liang Tsai, Ching-Chang Lin
Journal of Marine Science and Technology
The solution, based on Neumann's theory, for the content distribution of a diffusion material in a semi-infinite medium is applicable for the case in which a diffusion material diffuses from one side of a plate medium to the other side. After the diffusion material reaches the other side, the penetration rate of the diffusion material is solved using Fick's diffusion law. In this study, concrete plates are manufactured and submerged individually in special containers with saltwater on one side and freshwater on the other side, and no electric charge is applied. The amount of chloride penetrating the plate is monitored. …
Elastic Modulus Of Concrete Affected By Elastic Moduli Of Mortar And Artificial Aggregate, Chung-Chia Yang, Yon-Yer Lin, Ran Huang
Elastic Modulus Of Concrete Affected By Elastic Moduli Of Mortar And Artificial Aggregate, Chung-Chia Yang, Yon-Yer Lin, Ran Huang
Journal of Marine Science and Technology
The effect of two artificial aggregate types and three kinds of mortar on the elastic modulus of concrete are reported. Bighteen batches of concrete with various volume fractions (10%, 20%, and 30%) were selected. Theoretical moduli were calculated based on micromechanics. Following recent studies of concrete as a twophase composite material, this study examines whether there is a relation between the elastic modulus of the constituents and concrete. From the examination of available experimental results, it is apparent that elastic modulus of concrete is affected by elastic modulus of constituents and volume fraction of aggregate. Test results were compared with …
Aggregate Effect On Elastic Moduli Ofcement-Based Composite Materials, C.C. Yang, R. Huang, W. Yeih, I.C. Sue
Aggregate Effect On Elastic Moduli Ofcement-Based Composite Materials, C.C. Yang, R. Huang, W. Yeih, I.C. Sue
Journal of Marine Science and Technology
The elastic moduli of cement-based composite materials with different types of aggregates were investigated in this study. Twelve mixes with various volume fractions (10%, 20%, and 30% ) were selected. Cylindrical specimens with a dimension of ∮ 10 x 20 cm were cast and tested. Electric strain gages were used and elastic moduli were obtained from the stressstrain curves. Theoretical moduli were calculated based on H-S bounds and micromechanics. Test results show that the types and volume fractions of aggregates significantly affect the elastic moduli of concrete composite materials and the theoretical predictions fairly agree with the experimental data.
A Study Of Chloride Diffusion Properties Of Concrete At Early Age, W.D. Yeih, R. Huang, J.J. Chang
A Study Of Chloride Diffusion Properties Of Concrete At Early Age, W.D. Yeih, R. Huang, J.J. Chang
Journal of Marine Science and Technology
Existence of chloride ions in concrete may accelerate reinforcement corrosion. Chloride ions can penetrate into the concrete by the diffusion process even if no major cracks exist. It is well known that properties of concrete will change with time since the hydration reaction continues for a long time, which implies that the diffusion coefficient of concrete is a time-dependent function. In this research, the diffusion behavior is focused on early-age mortar and concrete. It is shown that the diffusion coefficient changes dramatically at early age; and the control of interface property is significantly important to chloride diffusion. The effect by …