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Every year, ceramic tile factories and the iron smelting industry produce huge amounts of waste ceramic tiles and blast furnace slag (BFS), respectively. In the field of construction materials, this waste can be used as a raw material for binders, thus reducing landfill waste and mitigating environmental pollution. The purpose of this study was to mix waste ceramic powder (WCP) into BFS paste and mortar activated by sodium silicate and sodium hydroxide to study its effect on performance. BFS was partially replaced by WCP at the rate of 10–30% by weight. Some experimental studies were conducted on, for example, the fluidity, heat of hydration, compressive strength testing, ultrasonic pulse velocity (UPV), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), electrical resistivity, sulfuric acid attack, and chloride ion diffusion coefficient. Based on the results of these experiments, the conclusions are: (1) increasing the amount of waste ceramic powder in the mixture can improve the fluidity of the alkali-activated paste; (2) adding waste ceramic powder to the alkali-activated mortar can improve the resistance of the mortar to sulfuric acid; (3) adding waste ceramic powder to the alkali-activated mortar can increase the diffusion coefficient of chloride ions; (4) the early strength of alkali-activated mortar is affected by the Ca/Si ratio, while the later strength is affected by the change in the Si/Al ratio.
Gui-Yu Zhang; Yong-Han Ahn; Run-Sheng Lin; Xiao-Yong Wang. Effect of Waste Ceramic Powder on Properties of Alkali-Activated Blast Furnace Slag Paste and Mortar. Polymers 2021, 13, 2817 .
AMA StyleGui-Yu Zhang, Yong-Han Ahn, Run-Sheng Lin, Xiao-Yong Wang. Effect of Waste Ceramic Powder on Properties of Alkali-Activated Blast Furnace Slag Paste and Mortar. Polymers. 2021; 13 (16):2817.
Chicago/Turabian StyleGui-Yu Zhang; Yong-Han Ahn; Run-Sheng Lin; Xiao-Yong Wang. 2021. "Effect of Waste Ceramic Powder on Properties of Alkali-Activated Blast Furnace Slag Paste and Mortar." Polymers 13, no. 16: 2817.
This study presents the workability, mechanical properties, ultrasonic pulse velocity (UPV), heat of hydration, degree of hydration, hydration products, durability (chloride ion diffusion and electrical resistivity), mesostructure, and microstructure of biochar blended specimens with various biochar contents (2% and 5% of cement). Based on the various test results, we found that (1) the workability decreases with an increase in the biochar replacement ratio. (2) The addition of biochar reduces the compressive strength, and compared with the early age, the reduction in strength at later ages is less obvious. (3) The addition of biochar reduces the UPV. For all specimens at various ages, the compressive strength can be regressed as an exponential function of the UPV. (4) With the increase in biochar content, the cumulative heat decreases. Compared with the dilution effect, the nucleation effect of biochar is marginal. (5) X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that as the biochar content increases, the Ca(OH)2 content decreases. Moreover, the TGA results showed that as the biochar content increases, the degree of cement hydration decreases. (6) As the biochar content increases, the chloride diffusivity increases. Moreover, because biochar is non-conductive, the electrical resistivity increases with increasing biochar content. (7) Optical micrographs showed that as the biochar content increases, the meso air voids also increase. Moreover, scanning electron microscopy (SEM) analysis revealed that the internal pores of biochar particles can provide space for the formation of hydration products.
Xu Yang; Xiao-Yong Wang. Hydration-strength-durability-workability of biochar-cement binary blends. Journal of Building Engineering 2021, 42, 103064 .
AMA StyleXu Yang, Xiao-Yong Wang. Hydration-strength-durability-workability of biochar-cement binary blends. Journal of Building Engineering. 2021; 42 ():103064.
Chicago/Turabian StyleXu Yang; Xiao-Yong Wang. 2021. "Hydration-strength-durability-workability of biochar-cement binary blends." Journal of Building Engineering 42, no. : 103064.
Slag is increasingly unitized for the production of sustainable concrete. This paper presents a procedure with which to analyze the property development of slag composite concrete. Experimental studies of the hydration heat and compressive strength development and simulation studies using a kinetic hydration model and a thermodynamic model were performed. First, we performed an experimental study of the isothermal hydration heat of cement–slag blends. Based on the results of the experimental study on cumulative hydration heat, the reaction degree of slag was determined. We found that the reaction degree of slag decreased as the slag content increased. Second, the reaction degree of slag and cement were used as the input parameters for the Gibbs energy minimization (GEM) thermodynamic equilibrium model. Moreover, the phase assemblage of hydrating cement–slag was determined. The trends of calcium silicate hydrate (CSH) are similar to those of strength. Based on the CSH content, the strength of hardening cement–slag blends was determined. In addition, the calcium hydroxide (CH) content resulting from the thermodynamic model shows good agreement with the experimental results. In summary, the integrated kinetic–thermodynamic model is useful for analyzing the properties of cement–slag blends.
Ki-Bong Park; Yi-Sheng Wang; Xiao-Yong Wang. Property Analysis of Slag Composite Concrete Using a Kinetic–Thermodynamic Hydration Model. Applied Sciences 2021, 11, 7191 .
AMA StyleKi-Bong Park, Yi-Sheng Wang, Xiao-Yong Wang. Property Analysis of Slag Composite Concrete Using a Kinetic–Thermodynamic Hydration Model. Applied Sciences. 2021; 11 (16):7191.
Chicago/Turabian StyleKi-Bong Park; Yi-Sheng Wang; Xiao-Yong Wang. 2021. "Property Analysis of Slag Composite Concrete Using a Kinetic–Thermodynamic Hydration Model." Applied Sciences 11, no. 16: 7191.
The cement industry has been increasing, and while meeting our construction needs, it has also brought environmental pollution. At present, reducing carbon emissions is an increasingly serious challenge facing the cement industry. The utilization of mineral admixtures (such as calcined clay, slag, and limestone powder) to replace partial cement is a direct way to lower CO2 emission. In this study, three supplementary cementitious materials (SCMs), i.e., limestone powder (0–10%), calcined Hwangtoh clay (0–20%), and granulated blast furnace slag (0–30%), were used to prepare binary, ternary, and quaternary mixtures. X-ray diffraction and attenuated total reflection Fourier transform infrared analysis were performed to characterize the mixed pastes. Furthermore, the workability, compressive strength, ultrasonic pulse velocity, surface resistivity, and heat of hydration of the mixed pastes were determined. In addition, we analyzed the sustainability of the quaternary mixed paste. The experimental results show that the calcined Hwangtoh clay can significantly reduce the workability of the cement paste. As SCM's content increases, the compressive strength, ultrasonic pulse velocity, cumulative heat of hydration, and carbon emissions of the mixed paste decreased while the surface resistivity increases. The compressive strength and ultrasonic pulse velocity have an apparent linear relationship (R2 = 0.923). The quaternary mixed paste has the highest corrosion resistance and the lowest cumulative heat of hydration. Compared with pure cement paste, a paste containing a large amount of SCMs can reduce carbon emissions per unit strength. In summary, the quaternary mixed paste produced in this study is highly durable and sustainable and thus has wide application prospects.
Yi Han; Runsheng Lin; Xiao-Yong Wang. Performance and sustainability of quaternary composite paste comprising limestone, calcined Hwangtoh clay, and granulated blast furnace slag. Journal of Building Engineering 2021, 43, 102655 .
AMA StyleYi Han, Runsheng Lin, Xiao-Yong Wang. Performance and sustainability of quaternary composite paste comprising limestone, calcined Hwangtoh clay, and granulated blast furnace slag. Journal of Building Engineering. 2021; 43 ():102655.
Chicago/Turabian StyleYi Han; Runsheng Lin; Xiao-Yong Wang. 2021. "Performance and sustainability of quaternary composite paste comprising limestone, calcined Hwangtoh clay, and granulated blast furnace slag." Journal of Building Engineering 43, no. : 102655.
CO2 uptake due to carbonation is an important issue for sustainability in the concrete industry. This study presents an analysis model of CO2 uptake of slag-blended concrete considering the service stage and the recycling stage. First, a slag-blended cement hydration model is used to evaluate the content of carbonatable substances, porosity, and diffusivity. Regarding the service stage, a one-dimensional carbonation model is proposed to evaluate carbonation depth. For the recycling stage, an unreacted core model is proposed to evaluate the carbonation fraction of crushed, spherical concrete. Second, CO2 uptake in the service stage and recycling stage is determined based on the carbonated fraction, shape of the concrete element, concrete component, and exposure conditions. The total CO2 uptake ratio is determined based on the content of CO2 uptake and CO2 emissions. Third, the analysis results show that for concrete with a water-to-binder ratio of 0.3, as the slag replacement ratio increases from 0 to 50%, the total CO2 uptake ratio increases from 21.43 to 28.87%. For concrete with 50% slag as the binder, as the water-to-binder ratio increases from 0.30 to 0.35, the total CO2 uptake ratio increases from 28.87 to 30.59%. The sizes and types of the structural elements and the diameter of the crushed concrete can impact the rate of CO2 uptake, but do not modify the total CO2 uptake ratio.
Xiao-Yong Wang. CO2 uptake of slag-blended concrete. Environmental Science and Pollution Research 2021, 1 -15.
AMA StyleXiao-Yong Wang. CO2 uptake of slag-blended concrete. Environmental Science and Pollution Research. 2021; ():1-15.
Chicago/Turabian StyleXiao-Yong Wang. 2021. "CO2 uptake of slag-blended concrete." Environmental Science and Pollution Research , no. : 1-15.
This study focuses on the effects of superabsorbent polymers (SAP) and belite-rich Portland cement (BPC) on the compressive strength, autogenous shrinkage (AS), and micro- and macroscopic performance of sustainable, ultra-high-performance paste (SUHPP). Several experimental studies were conducted, including compressive strength, AS, isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), attenuated total reflectance (ATR)–Fourier-transform infrared spectroscopy (FTIR), ultra-sonic pulse velocity (UPV), and electrical resistivity. The following conclusions can be made based on the experimental results: (1) a small amount of SAP has a strength promotion effect during the first 3 days, while BPC can significantly improve the strength over the following 28 days. (2) SAP slows down the internal relative humidity reduction and effectively reduces the development of AS. BPC specimens show a lower AS than other specimens. The AS shows a linear relationship with the internal relative humidity. (3) Specimens with SAP possess higher cumulative hydration heat than control specimens. The slow hydration rate in the BPC effectively reduces the exothermic heat. (4) With the increase in SAP, the calcium hydroxide (CH) and combined water content increases, and SAP thus improves the effect on cement hydration. The contents of CH and combined water in BPC specimens are lower than those in the ordinary Portland cement (OPC) specimen. (5) All samples display rapid hydration of the cement in the first 3 days, with a high rate of UPV development. Strength is an exponential function of UPVs. (6) The electrical resistivity is reduced due to the increase in porosity caused by the release of water from SAP. From 3 to 28 days, BPC specimens show a greater increment in electrical resistivity than other specimens.
Mei-Yu Xuan; Yi-Sheng Wang; Xiao-Yong Wang; Han-Seung Lee; Seung-Jun Kwon. Effect of Cement Types and Superabsorbent Polymers on the Properties of Sustainable Ultra-High-Performance Paste. Materials 2021, 14, 1497 .
AMA StyleMei-Yu Xuan, Yi-Sheng Wang, Xiao-Yong Wang, Han-Seung Lee, Seung-Jun Kwon. Effect of Cement Types and Superabsorbent Polymers on the Properties of Sustainable Ultra-High-Performance Paste. Materials. 2021; 14 (6):1497.
Chicago/Turabian StyleMei-Yu Xuan; Yi-Sheng Wang; Xiao-Yong Wang; Han-Seung Lee; Seung-Jun Kwon. 2021. "Effect of Cement Types and Superabsorbent Polymers on the Properties of Sustainable Ultra-High-Performance Paste." Materials 14, no. 6: 1497.
Previous studies mainly focus on the anti-corrosion performance of corrosion inhibitor, and very limit study is done about the construction technology of application of corrosion inhibitors into hardened concrete. Here, an experiment was conducted to inject of corrosion inhibitors into concrete under sufficiently high pressure, measure the penetration properties of corrosion inhibitors and the nitrite ion concentrations at various regions in the concrete by utilizing penetration theory, and clarify the corrosion inhibition mechanisms, water permeability of concrete, and concentration ratios of nitrite ions to chloride ions. The results revealed that the water-cement ratio greatly influences the corrosion inhibitor; similar results were obtained with respect to water penetration. Based on these results, we proposed a predictive equation for the penetration of corrosion inhibitors and calculated the ratio of nitrite ions to chloride ions with a molar ratio of 0.6. Finally, the pressure and pressurizing time were proven to be crucial factors in measuring the nitrite ion concentration in concrete.
Xiao-Yong Wang; Seokhee Lee; HyeongKyu Cho. Penetration properties and injecting conditions of corrosion inhibitor for concrete. Construction and Building Materials 2021, 284, 122761 .
AMA StyleXiao-Yong Wang, Seokhee Lee, HyeongKyu Cho. Penetration properties and injecting conditions of corrosion inhibitor for concrete. Construction and Building Materials. 2021; 284 ():122761.
Chicago/Turabian StyleXiao-Yong Wang; Seokhee Lee; HyeongKyu Cho. 2021. "Penetration properties and injecting conditions of corrosion inhibitor for concrete." Construction and Building Materials 284, no. : 122761.
This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.
Guang-Zhu Zhang; Xiao-Yong Wang; Tae-Wan Kim; Jong-Yeon Lim; Yi Han. The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar. Sustainability 2021, 13, 2407 .
AMA StyleGuang-Zhu Zhang, Xiao-Yong Wang, Tae-Wan Kim, Jong-Yeon Lim, Yi Han. The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar. Sustainability. 2021; 13 (4):2407.
Chicago/Turabian StyleGuang-Zhu Zhang; Xiao-Yong Wang; Tae-Wan Kim; Jong-Yeon Lim; Yi Han. 2021. "The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar." Sustainability 13, no. 4: 2407.
In this study, the total maintenance cost for public houses in South Korea was analyzed, and the effect of each repair process on the total maintenance cost was evaluated with probabilistic and deterministic methods. In the probabilistic method, quality of repair materials and construction skills were considered in the variability of extended service life through repair, while the deterministic method considered it by simple summation of repair step. The repair cost was analyzed considering the coefficient of variation (COV) of extended service life, so the reasonable total maintenance cost was able to be evaluated. Since the results through the probabilistic method provided a continuous cost line, a reasonable repair strategy was carried out by simply changing the intended service life of the structure. The repair cost was additionally analyzed with constant COV (0.15) of each repair process for considering various situations. The analysis results with a COV of 0.15 exhibited a slightly higher maintenance cost than those with current COV. The total maintenance costs can be adjusted if the initial repair timing is extended to the largest possible extent for the highest-repair-cost process since the total repair cost is dominated by the process with the highest repair cost.
Yong-Sik Yoon; Yong-Han Ahn; Xiao-Yong Wang; Seung-Jun Kwon. Total Repair Cost Simulation Considering Multiple Probabilistic Measures and Service Life. Sustainability 2021, 13, 2350 .
AMA StyleYong-Sik Yoon, Yong-Han Ahn, Xiao-Yong Wang, Seung-Jun Kwon. Total Repair Cost Simulation Considering Multiple Probabilistic Measures and Service Life. Sustainability. 2021; 13 (4):2350.
Chicago/Turabian StyleYong-Sik Yoon; Yong-Han Ahn; Xiao-Yong Wang; Seung-Jun Kwon. 2021. "Total Repair Cost Simulation Considering Multiple Probabilistic Measures and Service Life." Sustainability 13, no. 4: 2350.
This study examines the hydration–mechanical–autogenous shrinkage–durability–sustainability properties of ternary composites with limestone filler (LF) and ground-granulated blast furnace slag (BFS). Four mixtures were prepared with a water/binder ratio of 0.3 and different replacement ratios varying from 0 to 45%. Multiple experimental studies were performed at various ages. The experimental results are summarized as follows: (1) As the replacement levels increased, compressive strength and autogenous shrinkage (AS) decreased, and this relationship was linear. (2) As the replacement levels increased, cumulative hydration heat decreased. At the age of 3 and 7 days, there was a linear relationship between compressive strength and cumulative hydration heat. (3) Out of all mixtures, the ultrasonic pulse velocity (UPV) and electrical resistivity exhibited a rapid increase in the early stages and tended to slow down in the latter stages. There was a crossover of UPV among various specimens. In the later stages, the electrical resistivity of ternary composite specimens was higher than plain specimens. (4) X-ray diffraction (XRD) results showed that LF and BFS have a synergistic effect. (5) With increasing replacement ratios, the CO2 emissions per unit strength reduced, indicating the sustainability of ternary composites.
Mei-Yu Xuan; Yi Han; Xiao-Yong Wang. The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites. Sustainability 2021, 13, 1881 .
AMA StyleMei-Yu Xuan, Yi Han, Xiao-Yong Wang. The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites. Sustainability. 2021; 13 (4):1881.
Chicago/Turabian StyleMei-Yu Xuan; Yi Han; Xiao-Yong Wang. 2021. "The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites." Sustainability 13, no. 4: 1881.
Calcined hwangtoh is a pozzolanic material that is increasingly being used as a mineral admixture in the concrete industry. This study shows a hydration model for cement–hwangtoh blends and evaluates the various properties of hwangtoh-blended concrete using reaction degrees of binders. First, a kinetic reaction model is proposed for analyzing the pozzolanic reaction of hwangtoh. The reaction of hwangtoh includes three processes: the initial dormant period, boundary reaction process, and diffusion process. The mutual interactions between the binary reactions of cement and hwangtoh are thought to be in line with the items in capillary water and calcium hydroxide. Second, the reaction degrees of cement and hwangtoh are determined based on a blended hydration model. Furthermore, the chemical (chemically combined water and calcium hydroxide contents), mechanical (compressive strength), thermal (hydration heat), and durability aspects (carbonation depth) of hwangtoh-blended concrete are systematically predicted. The results show good agreement with experimental results.
Han-Seung Lee; Xiao-Yong Wang. Hydration Model and Evaluation of the Properties of Calcined Hwangtoh Binary Blends. International Journal of Concrete Structures and Materials 2021, 15, 1 -15.
AMA StyleHan-Seung Lee, Xiao-Yong Wang. Hydration Model and Evaluation of the Properties of Calcined Hwangtoh Binary Blends. International Journal of Concrete Structures and Materials. 2021; 15 (1):1-15.
Chicago/Turabian StyleHan-Seung Lee; Xiao-Yong Wang. 2021. "Hydration Model and Evaluation of the Properties of Calcined Hwangtoh Binary Blends." International Journal of Concrete Structures and Materials 15, no. 1: 1-15.
This study clarifies the effects of pre-soaked zeolite sand as an internal curing material on the hydration, strength, autogenous shrinkage, and durability of alkali-activated slag (AAS) mortars. The liquid-to-binder ratio (L/b) of all of the AAS mortars was 0.55. Sodium hydroxide solution was used as an alkali activator and an internal curing liquid. Calcined zeolite and natural zeolite sand replaced the standard sand at 15% and 30%, respectively. The setting time, autogenous shrinkage, compressive strength, ultrasonic pulse velocity, and surface electrical resistivity were tested. The following conclusions were drawn: (1) The addition of zeolite significantly reduces the autogenous shrinkage of AAS mortar. Compared with the control group, 30% calcined zeolite reduced the autogenous shrinkage by 96.4%. Moreover, the autogenous shrinkage of the AAS mortars was noticed in two stages (a variable temperature stage and an ambient temperature stage), and the two stages split at one day of age. (2) The compressive strength of all of the specimens increased as the zeolite sand content increased, and the highest compressive strength was obtained for AAS combined with 30% natural zeolite sand. (3) Internal curing accelerated the formation of the second peak of heat flow and reduced the accumulated heat release. (4) Calcined zeolite sand delayed the setting time of the AAS mortars. (5) The addition of zeolite significantly reduced the surface electrical resistivity of the AAS mortars. In summary, zeolite sand is extremely useful as an internal curing agent to reduce autogenous shrinkage and to increase the compressive strength of AAS mortars.
Guang-Zhu Zhang; Han-Seung Lee; Xiao-Yong Wang; Yi Han. Internal Curing Effect of Pre-Soaked Zeolite Sand on the Performance of Alkali-Activated Slag. Materials 2021, 14, 718 .
AMA StyleGuang-Zhu Zhang, Han-Seung Lee, Xiao-Yong Wang, Yi Han. Internal Curing Effect of Pre-Soaked Zeolite Sand on the Performance of Alkali-Activated Slag. Materials. 2021; 14 (4):718.
Chicago/Turabian StyleGuang-Zhu Zhang; Han-Seung Lee; Xiao-Yong Wang; Yi Han. 2021. "Internal Curing Effect of Pre-Soaked Zeolite Sand on the Performance of Alkali-Activated Slag." Materials 14, no. 4: 718.
In this study, a model for evaluating the CO2 uptake rate of plain concrete and limestone-powder-blended concrete in both the service and recycling phases was proposed. First, a blended cement hydration model was proposed to evaluate the content of carbonatable substances, porosity and carbon dioxide diffusivity. In the service phase, a one-dimensional carbonation model was proposed to evaluate the carbonation depth. In the recycling stage, an unreacted core model was proposed to evaluate the carbonation process of spherical recycled concrete. Secondly, considering the concrete materials, structural elements and environmental exposure, a CO2 uptake model at the service stage and recycling stage was proposed. The total CO2 uptake rate is the sum of the CO2 uptake rates in the service stage and the recycling stage. The analysis results showed (1) as the limestone replacement rate increased from 0% to 20% (water–binder ratio is 0.3), the CO2 uptake rate in the service phase increased from 3.12% to 3.84%, and the total CO2 uptake rate increased from 22.82% to 26.11%. (2) Given a certain concrete mixture, as the surface area to volume ratio of structural units increased, or the amount of recycled concrete decreased, the CO2 uptake rate increased, but the total CO2 uptake rate did not change. (3) Given a certain limestone powder replacement ratio, as the water/binder ratio increased, the total CO2 uptake ratio increased. The contributions of this study are 1) propose an integrated hydration-carbonation-CO2 uptake model for limestone blended concrete, 2) clarify the differences of carbonation equations between service stage and recycling stage, and 3) determine the effects of concrete mixtures, structural element sizes and types, life cycle stages, and recycled concrete sizes on CO2 uptake.
Seung-Jun Kwon; Xiao-Yong Wang. CO2 uptake model of limestone-powder-blended concrete due to carbonation. Journal of Building Engineering 2021, 38, 102176 .
AMA StyleSeung-Jun Kwon, Xiao-Yong Wang. CO2 uptake model of limestone-powder-blended concrete due to carbonation. Journal of Building Engineering. 2021; 38 ():102176.
Chicago/Turabian StyleSeung-Jun Kwon; Xiao-Yong Wang. 2021. "CO2 uptake model of limestone-powder-blended concrete due to carbonation." Journal of Building Engineering 38, no. : 102176.
In this study, the macro properties (residual compressive strength), meso properties (mesoscopic images), and micro properties (reaction products and pore structures) of paste specimens with various limestone and calcined clay contents at elevated temperatures (20, 300, 550, and 900 °C) are experimentally investigated. According to the experimental results, (1) the strengths of all samples increase at 300 °C, while those of the LC3 ternary blended pastes increase more significantly because of the formation of katoite and the further hydration of binders. After the treatments at 550 and 900 °C, the reduction in the strengths of the LC3 samples is greater than that of the plain paste. (2) With further increasing temperature, all samples generate more meso cracks. (3) At 900 °C, a large gehlenite crystalline phase is formed in the samples with calcined clay. In summary, the microscopic explanation for the macroscopic and mesoscopic properties of LC3 paste at elevated temperature is investigated.
Run-Sheng Lin; Yi Han; Xiao-Yong Wang. Macro–meso–micro experimental studies of calcined clay limestone cement (LC3) paste subjected to elevated temperature. Cement and Concrete Composites 2020, 116, 103871 .
AMA StyleRun-Sheng Lin, Yi Han, Xiao-Yong Wang. Macro–meso–micro experimental studies of calcined clay limestone cement (LC3) paste subjected to elevated temperature. Cement and Concrete Composites. 2020; 116 ():103871.
Chicago/Turabian StyleRun-Sheng Lin; Yi Han; Xiao-Yong Wang. 2020. "Macro–meso–micro experimental studies of calcined clay limestone cement (LC3) paste subjected to elevated temperature." Cement and Concrete Composites 116, no. : 103871.
Ultra-high-strength paste (UHSP) combined with nanomaterials has been extensively studied. However, the research on nano-ZrO2 is limited. In this study, UHSP with various nano-ZrO2 contents is analyzed. The motivation of this study is to clarify the effects of nano-ZrO2 on the hydration products, strength, autogenous shrinkage, and hydration heat of UHSPs. The water-to-binder ratio (w/b) of the specimens is 0.2. The nano-ZrO2 content is 0, 1.5, and 3 wt.%. The strength is measured at the age of 3, 7, and 28 days. The hydration heat is measured from the mixing stage to 3 days. The hydration products are analyzed by X-ray diffraction (XRD) and thermogravimetric analysis (TG). The autogenous shrinkage is measured from the mixing stage for 7 days using a new experimental device. The new experimental device can measure autogenous shrinkage, internal relative humidity, and internal temperature simultaneously. The following conclusions can be drawn based on the experimental studies: (1) Two stages were noticed in the autogenous shrinkage of UHSPs: a variable-temperature stage and a room-temperature stage. The cut-off point of these two stages occurred in roughly 1.5 days. Furthermore, in the room-temperature stage, there was a straight-line relationship between the autogenous shrinkage and internal relative humidity. (2) With the increase of the nano-ZrO2 amount, the compressive strength at 3 days, 7 days, and 4 weeks increased. (3) With the nano-ZrO2 increasing, the flow decreased. (4) With the nano-ZrO2 increasing, the hydration heat increased due to the physical nucleation effect of the nano-ZrO2. Furthermore, the nano-ZrO2 used in this study was chemically inert and did not take part in the cement hydration reaction based on the XRD, differential thermal, and TG data. This paper is of great significance for the development of high-strength cementitious materials doped with nano-ZrO2.
Guang-Zhu Zhang; Han-Seung Lee; Xiao-Yong Wang. Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High-Strength Paste Incorporating Nano-Zirconium Dioxide. Sustainability 2020, 12, 9372 .
AMA StyleGuang-Zhu Zhang, Han-Seung Lee, Xiao-Yong Wang. Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High-Strength Paste Incorporating Nano-Zirconium Dioxide. Sustainability. 2020; 12 (22):9372.
Chicago/Turabian StyleGuang-Zhu Zhang; Han-Seung Lee; Xiao-Yong Wang. 2020. "Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High-Strength Paste Incorporating Nano-Zirconium Dioxide." Sustainability 12, no. 22: 9372.
Hwangtoh clay is a type of kaolin clay, which is used as an environment-friendly material in constructions. This study presents multiple experimental studies on the hydration, strength, and durability properties of ternary or binary composites, with calcined Hwangtoh clay and limestone powder. The replacement levels of calcined Hwangtoh clay and limestone powder in the composite were in the ranges of 0%–30%, and 0%–15%, respectively. Multiple experimental studies involving compressive strength tests, isothermal calorimetry, thermogravimetric analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, electrical resistivity, and carbonation were performed. The corresponding experimental results indicated the following: 1) among all the mixtures, the ternary composite with a 15% replacement level provided the most optimal mixture, and 30% replacement level was the threshold level for achieving a similar strength as that of plain concrete; 2) for all the mixtures aged 3–270 days, there was a linear relationship between the strength and combined water; 3) for the ternary composite, the contents of hemicarboaluminate (Hc) became more evident as the amount of Hwangtoh was increased, which showed a synergic relation between the calcined clay and limestone; 4) for the ternary composite, as the replacement levels of limestone and Hwangtoh were increased, the electrical resistivity increased significantly, and so did the carbonation degree; and finally, (5) compared to strength, the combined water was a better indicator for judging the carbonation resistance of the blended concrete.
Run-Sheng Lin; Han-Seung Lee; Yi Han; Xiao-Yong Wang. Experimental studies on hydration–strength–durability of limestone-cement-calcined Hwangtoh clay ternary composite. Construction and Building Materials 2020, 269, 121290 .
AMA StyleRun-Sheng Lin, Han-Seung Lee, Yi Han, Xiao-Yong Wang. Experimental studies on hydration–strength–durability of limestone-cement-calcined Hwangtoh clay ternary composite. Construction and Building Materials. 2020; 269 ():121290.
Chicago/Turabian StyleRun-Sheng Lin; Han-Seung Lee; Yi Han; Xiao-Yong Wang. 2020. "Experimental studies on hydration–strength–durability of limestone-cement-calcined Hwangtoh clay ternary composite." Construction and Building Materials 269, no. : 121290.
Limestone powder has increasingly been employed in the production of sustainable concrete. This research shows an optimal design framework for the design of low-CO2 blended concrete with limestone, considering strength, workability, and carbonation durability in the context of global warming. First, the purpose of the optimal design, i.e., to reduce CO2 emissions, is explained. The restrictions of the optimal design include design strength, design workability, carbonation service life in the context of global warming, component ratio, component range, and absolute volume. The compressive strength and carbonation depth are evaluated using a hydration-based integrated model. Second, concrete mixtures, with different strength levels, are determined based on a genetic algorithm. The results of a low-CO2 concrete mixture for carbonation durability in the context of global warming are provided. The suggested method can find a threshold strength, which could allow for the isolation of the control factor of the mixture design, for example, a carbonation durability control or strength control. In addition, the threshold strength of the mixture design increases with global warming.
Xiao-Yong Wang. Optimal mix design of low-CO2 blended concrete with limestone powder. Construction and Building Materials 2020, 263, 121006 .
AMA StyleXiao-Yong Wang. Optimal mix design of low-CO2 blended concrete with limestone powder. Construction and Building Materials. 2020; 263 ():121006.
Chicago/Turabian StyleXiao-Yong Wang. 2020. "Optimal mix design of low-CO2 blended concrete with limestone powder." Construction and Building Materials 263, no. : 121006.
Slag is an industry by-product of steel-making factories that is widely found in the concrete industry. This study shows a framework for evaluating the hydration heat, reaction amount, and strength progress of cement–slag binary composites at different temperatures. First, we conducted a test to measure the isothermal hydration heat of slag composite paste at various temperatures. Based on the experimental results with cumulative hydration heat, the coefficients of the kinetic reaction type of slag were determined. In addition, the reaction quantity of slag was calculated utilizing a slag reaction model. We found that the reaction amount of slag is significantly improved at elevated temperatures. The reaction quantity of slag decreases with an increasing content of slag. Second, using the reaction quantity of slag and cement, we created a straight-line equation for evaluating the strength progress of binary composites. The strength progress model applies to a number of slag substitution ratios and curing temperatures. The hydration-based strength model shows better analysis results than maturity-based models.
Xiao-Yong Wang. Analysis of hydration kinetics and strength progress in cement–slag binary composites. Journal of Building Engineering 2020, 35, 101810 .
AMA StyleXiao-Yong Wang. Analysis of hydration kinetics and strength progress in cement–slag binary composites. Journal of Building Engineering. 2020; 35 ():101810.
Chicago/Turabian StyleXiao-Yong Wang. 2020. "Analysis of hydration kinetics and strength progress in cement–slag binary composites." Journal of Building Engineering 35, no. : 101810.
In this paper, the effect of nano-silica on the autogenous shrinkage, hydration heat, compressive strength hydration products of Ultra-High Strength Concrete (UHSC) is studied. The water/binder ratio (w/b) of UHSC is 0.2. The nano-silica replaces 2% and 4% of the mass fraction of the cement in UHSCs, respectively. A new instrument was developed to simultaneously measure the autogenous shrinkage, internal relative humidity, and internal temperature of UHSC. The following results were obtained from the analysis of the experimental data: 1) The trends in the autogenous shrinking of UHSC can be divided into two stages, which are the variable temperature stage and the room temperature stage. The dividing point between the two stages occurs at the age of approximately 2 days. During the room temperature stage, the internal relative humidity and autogenous shrinkage showed a good linear relationship. 2) The compressive strength of UHSC increased significantly with the increase of nano-silica content at 3 days, 7 days, and 28 days. 3) The total accumulated heat of UHSC increased during the 72 h, with the increasing of nano-silica content. 4) The XRD data at the age of 28 days showed that the Ca(OH)2 peaks of nS2 and nS4 have a tendency to weaken due to the pozzolanic reaction, compared with the peak of nS0.
Guang-Zhu Zhang; Hyeong-Kyu Cho; Xiao-Yong Wang. Effect of Nano-Silica on the Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High Strength Concrete. Applied Sciences 2020, 10, 5202 .
AMA StyleGuang-Zhu Zhang, Hyeong-Kyu Cho, Xiao-Yong Wang. Effect of Nano-Silica on the Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High Strength Concrete. Applied Sciences. 2020; 10 (15):5202.
Chicago/Turabian StyleGuang-Zhu Zhang; Hyeong-Kyu Cho; Xiao-Yong Wang. 2020. "Effect of Nano-Silica on the Autogenous Shrinkage, Strength, and Hydration Heat of Ultra-High Strength Concrete." Applied Sciences 10, no. 15: 5202.
Fly ash is increasingly used for producing sustainable concrete. This paper outlines a procedure for the optimal mixture design of air-entrained fly ash-blended concrete considering carbonation and frost durability. First, the aim function of the optimization is set as the total cost, which equals the material cost plus the CO2 emission cost. Constraints such as mechanical, workability, carbonation, and frost durability properties are considered during the optimization design procedure. The carbonation model considers the effect of global warming, including increasing CO2 concentration and environmental temperature. Second, a genetic algorithm is used for determining the optimal concrete mixtures. A total of 12 design examples are prepared for various frost exposure conditions (including mild, moderate, and severe exposure), and the effects of the carbonation durability and climate change on the mixture design are highlighted. According to the results, 1) for ordinary-strength concrete (design strength of 30 MPa), the carbonation durability is the decisive factor in the mixture design, and the actual strength should be greater than the design strength; 2) for high-strength concrete (design strength of 45 MPa), strength is the decisive factor in the mixture design, and the actual strength can equal the design strength; 3) for a particular entrained air content, the total cost of concrete increases with increasing concrete strength. In summary, the proposed method is a general and useful approach for designing air-entrained fly ash-blended concrete considering sustainability and durability.
Xiao-Yong Wang. Design of low-cost and low-CO2 air-entrained fly ash-blended concrete considering carbonation and frost durability. Journal of Cleaner Production 2020, 272, 122675 .
AMA StyleXiao-Yong Wang. Design of low-cost and low-CO2 air-entrained fly ash-blended concrete considering carbonation and frost durability. Journal of Cleaner Production. 2020; 272 ():122675.
Chicago/Turabian StyleXiao-Yong Wang. 2020. "Design of low-cost and low-CO2 air-entrained fly ash-blended concrete considering carbonation and frost durability." Journal of Cleaner Production 272, no. : 122675.