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Articles 1 - 22 of 22
Full-Text Articles in Structural Materials
Mechanical Properties Of Engineering Cement-Based Materials Containing Modified Shape Memory Alloy Fiber, Song Mengfan
Mechanical Properties Of Engineering Cement-Based Materials Containing Modified Shape Memory Alloy Fiber, Song Mengfan
International Conference on Durability of Concrete Structures
在这项研究中，提出了一种 SMA 纤维的表面改性方法，以改善水泥基复合材料中纤维的界面性能。SMA 纤维涂有 SiO 2，预计会与 Ca(OH) 2反应由水泥水化形成，减少了薄弱区的可能性，并在纤维-基体界面处形成了更致密的微观结构。采用扫描电子显微镜 (SEM)、能量色散光谱 (EDS) 和红外吸收光谱 (IR) 对表面改性后的 SMA 纤维进行表征。此外，还进行了抗弯强度试验、抗压强度试验和四点弯曲试验，以评价宏观尺度上界面力学性能的增强情况。实验结果表明，包覆的 SiO 2，导致改性 SMA 纤维-水泥界面处的 CSH 凝胶量增加和孔隙率降低。改性后的SMA纤维与水泥基体之间的紧密粘附有利于建立更强的界面结合力，有利于提高抗弯强度、抗压强度、四点抗弯强度和挠度。抗弯强度、抗压强度、四点抗弯强度和挠度均在28d时显着增加。结果支持了所提出的表面改性方法适用于 SMA 纤维以提高其在工程水泥基材料中的增强效率的结论。
Mechanical Properties And Microstructure Of High Strength Lc3 Pastes With Varying Limestone/Calcined Clay Ratios And Different Curing Conditions, Yemin Dong
International Conference on Durability of Concrete Structures
研究（抗施工蒸馏）石石和石榴石在淀粉胶系统（即0标准和低水印）下的水胶系统（即0标准和低水墨）X射线比、水量值水量-电子背基相关研究.61.25 .25.25.25.0.25.25.25.25.25.0.25.25.25.25.25.1.25.7.25.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.25.1.25.25.1.25.1.25.1.25.1.25.1.25.1 .25.1.25.1.25.1.25.1.25.1.25.0.0.0.0.0.0.0.00.0.0.1.25.1.25.1.25.1.25.1.25.0.0.0.00.0.0.0.0.0.0.0.0.0.0.0.0.0.00.0 .00.0.00.X射线比值、水量-电子显微镜相关研究测量值。早期的水泥水化程度小水的压合含煤量，降低了水泥石的。因此，需要采用合适的钙铝内容和体系以提高碳系统的性能。
Study On The Effect Of Fly Ash On The Properties Of Potassium Magnesium Phosphate Cement, Bo Pang
Study On The Effect Of Fly Ash On The Properties Of Potassium Magnesium Phosphate Cement, Bo Pang
International Conference on Durability of Concrete Structures
In this paper, the effect of fly ash on the setting time and mechanical properties of potassium magnesium phosphate cement is studied. The early hydration process of potassium magnesium phosphate cement was studied by TAM-Air, and the hydration products were analyzed by XRD. The results show that fly ash can effectively prolong the setting time and the compressive strength of the cement paste was decreased; The addition of fly ash would not change the phase composition of the hydration products of the potassium magnesium phosphate cement, which affect the hydration process, the amount of the hydration products and the degree …
Study On Hydration Properties Of Grinded Tuff-Cement Cementitious Material System, Hao Wang
Study On Hydration Properties Of Grinded Tuff-Cement Cementitious Material System, Hao Wang
International Conference on Durability of Concrete Structures
The chemical composition and microscopic morphology characteristics of grinded tuff(GT) and fly ash(FA) were compared and analyzed in the paper. The chemical bound water content and hydration heat were tested for investigating the hydration properties of grinded tuff-cement cementitious material system (GTCS) and fly ash-cement cementitious material system (FACS). The results shown that, the chemical composition of GT was similar with that of FA, however the loss on ignition of the GT was obviously higher than FA. The microstructure of the GT particles was polygonal and irregular, while the microstructure of FA particles were mostly smooth spheres. The hydrated heat …
Investigation On The Properties Of Calcium Sulfoaluminate Cement Waterproof Repair Mortar Modified With Ethylene-Vinyl Acetate Powder, Dong Dong
International Conference on Durability of Concrete Structures
本文采用乙烯-醋酸乙烯酯（EVA）粉体和CSA水泥制备了防水修复砂浆，并对其水化和性能进行了研究。结果表明，EVA粉体延长了凝固时间，提高了防水修补砂浆的流动性，使其在实际工程中更容易应用。EVA粉提高了防水修复砂浆的不渗透性，降低了吸水性。虽然EVA粉降低了防水修补砂浆的抗弯强度和抗压强度，但它仍然符合JC/T 2381-2016标准对刚性修复砂浆的要求。EVA粉体降低了防水修复砂浆的收缩率，改善了界面过渡区和拉伸粘接强度、弯曲粘接强度等粘接性能。EVA粉末抑制CSA水泥的水合作用6 h，在3 d水化年龄时抑制作用消失。
Shrinkage And Durability Of Cement Mortars With Recycled Aggregates, Wencui Yang
Shrinkage And Durability Of Cement Mortars With Recycled Aggregates, Wencui Yang
International Conference on Durability of Concrete Structures
In recent years, the rapid growth of economy and urbanization process in China resulted in the massive construction and demolition wastes (C&DW). The reutilization of C&DW as recycled aggregates (RA) fully or partially to replace natural aggregates is an effective way to solve the environmental and economic problems caused by C&DW. The properties of cement mortars could be influenced by recycled fine aggregates due to their high absorption and the quantity of fine particles. This paper presents the main results of the research to explore the effect of recycled aggregate (RA) on shrinkage and durability properties of masonry mortars. Four …
Investigation On Structural Heritability And Durability Of High Sulfate Resistance Portland Cement Mortar Modified By Aluminum Salt, Jun Xu
International Conference on Durability of Concrete Structures
The essential hydration and hardened properties of high sulfate resistance Portland cement paste/mortar were investigated with Al2(SO4)3 as admixture. Experiment results showed that that the addition of Al2(SO4)3 promoted the hydration of HSRP cement pastes, and the hydration rate accelerated with the increase of the addition amount. The mechanical properties and chloride diffusion coefficient of cement mortar were obviously improved with 0.25% Al2(SO4)3 addition . For instance, the compressive strength of AS0.25 cement mortars was 24.8% higher than AS0 samples and the chloride ion migration …
Micro-Mechanical Analysis Of Corrosion Products Formed During Long-Term Carbonation Induced Corrosion Of Steel, Marijana Serdar, Dubravka Bjegovic, Valérie L’Hostis, Stéphane Poyet, Damien Féron
Micro-Mechanical Analysis Of Corrosion Products Formed During Long-Term Carbonation Induced Corrosion Of Steel, Marijana Serdar, Dubravka Bjegovic, Valérie L’Hostis, Stéphane Poyet, Damien Féron
International Conference on Durability of Concrete Structures
During corrosion distinct types of corrosion products form, composed of different ratios of ferrous ions and oxide, hydroxides. Corrosion products have different physical and mechanical properties, mainly density, resistivity, volume and modulus of elasticity compared to iron. Knowing properties of corrosion products is indispensable for service life modelling of structures and can give valuable insight into the long-term corrosion propagation process. In this study micro-indentation method was used to evaluate mechanical properties of different layers formed during long-term carbonation induced corrosion of steel in concrete. Investigation was performed on three sets of reinforced concrete samples, that underwent corrosion during 50, …
Development Of Engineered Cementitious Composites With Conductive Inclusions For Use In Self-Sensing Applications, Benny Suryanto Dr, Danah Saraireh Ms, Steven Walls Mr, Jaehwan Kim Dr, W John Mccarter Prof
Development Of Engineered Cementitious Composites With Conductive Inclusions For Use In Self-Sensing Applications, Benny Suryanto Dr, Danah Saraireh Ms, Steven Walls Mr, Jaehwan Kim Dr, W John Mccarter Prof
International Conference on Durability of Concrete Structures
The mechanical and a.c. electrical properties of a new varietal of engineered cementitious composite (ECC) incorporating conductive inclusions are presented. Electrical measurements were undertaken over a wide frequency range while curing and when under uniaxial tensile loading to study the influence of ongoing hydration and multiple microcrack formation on the composite electrical impedance. When presented in Nyquist format, the work shows that conductive inclusions reduce the bulk resistance of the composite while enhancing its polarizability, transforming the classic, single-arc bulk response of typical cement-based materials to a two-arc response. The bulk resistance was shown to increase with time and damage, …
Experimental And Numerical Investigation On The Irregularity Of Carbonation Depth Of Concrete Under Supercritical Condition, Hao Bao Masc, Min Yu Dr., Jianqiao Ye Dr., Lihua Xu Dr., Yin Chi Dr., J Ye
Experimental And Numerical Investigation On The Irregularity Of Carbonation Depth Of Concrete Under Supercritical Condition, Hao Bao Masc, Min Yu Dr., Jianqiao Ye Dr., Lihua Xu Dr., Yin Chi Dr., J Ye
International Conference on Durability of Concrete Structures
The heterogeneity of a cement-based material results in a random spatial distribution of carbonation depth, which may significantly affect the mechanical properties and durability of the material. Currently, there is a lack of both experimental and numerical investigations aiming at a statistical understanding of this important phenomenon. This paper presents both experimental and numerical supercritical carbonation test results of concrete blocks. The random fields of porosity and two-dimension random aggregate model of concrete were proposed for the simulation. The carbonation depths are measured and distributed along the carbonation boundary by the proposed rapid image processing technique, which are then statistically …
Guiding Principles In Developing The South African Approach To Durability Index Testing Of Concrete, Yunus Ballim, Mark Alexander
Guiding Principles In Developing The South African Approach To Durability Index Testing Of Concrete, Yunus Ballim, Mark Alexander
International Conference on Durability of Concrete Structures
Focused thinking on the possibility of early-age testing of concrete for long-term durability started in earnest during the late 1980’s in South Africa. Through sustained research, development and trial implementation on construction projects, three durability index (DI) tests have emerged, two of which have been adopted as national standard test methods for concrete construction, the remaining one being prepared a national standard. In this paper we review the guiding or foundational principles that directed the development of these DI tests, with a view to assessing the appropriateness and relevance of these guiding principles to modern concretes. The last 30 years …
The Influence Of Waste Glass Powder On The Chloride Binding Capacity Of Fly Ash/Cement Hardened Paste, Jh Yan, Tingyu Hao
The Influence Of Waste Glass Powder On The Chloride Binding Capacity Of Fly Ash/Cement Hardened Paste, Jh Yan, Tingyu Hao
International Conference on Durability of Concrete Structures
The potential of using waste glass powder to increase the chloride binding capacity of fly ash/cement hardened paste was investigated. When only fly ash replacing cement, the chloride binding capacity was raised within 28d when the fly ash replacement level was in the range from 30-50% by mass. But at a longer age of 60 to 90d, the binding performance was increased at the replacement level of 10-30wt%. The chloride binding capacity of glass powder-fly ash-cement system was increased by adding glass powder of 2% and 4% by mass at 7d while those at larger addition and longer age reduced. …
Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai
Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai
International Conference on Durability of Concrete Structures
Concretes used in marine environment are generally under the cyclic effect of CO2 and chloride ions (Cl-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate the progress of carbonation and ingress of Cl- in concretes. From the apparent pH profile, a carbonation front …
Corrosion Of Steel In Concrete And Its Prevention In Aggressive Chloride-Bearing Environments, Luca Bertolini, Maddalena Carsana, Matteo Gastaldi, Federica Lollini, Elena Redaelli
Corrosion Of Steel In Concrete And Its Prevention In Aggressive Chloride-Bearing Environments, Luca Bertolini, Maddalena Carsana, Matteo Gastaldi, Federica Lollini, Elena Redaelli
International Conference on Durability of Concrete Structures
This keynote paper deals with the durability of reinforced concrete (RC) structures exposed to aggressive environments characterized by high concentration of chloride ions, namely, marine environments or the use of de-icing salts. The mechanism of chloride-induced corrosion of steel in concrete is introduced, and its influence on the service life of RC structures is analyzed. Factors affecting the time to corrosion initiation are described with regard to both concrete properties and environmental exposure conditions. Design approaches available for achieving durability targets associated with the design service life are analyzed, focusing on studies carried out by the authors in recent years …
Finite Volume Numerical Analysis Of The Thermal Property Of Cellular Concrete Based On Two And Three Dimensional X-Ray Computerized Tomography Images, She Wei, Yang Yonggan, Xie Deqing, Zhang Yunsheng
Finite Volume Numerical Analysis Of The Thermal Property Of Cellular Concrete Based On Two And Three Dimensional X-Ray Computerized Tomography Images, She Wei, Yang Yonggan, Xie Deqing, Zhang Yunsheng
International Conference on Durability of Concrete Structures
Cellular concrete is one kind of lightweight concrete, which are widely used in thermal insulation engineering project. In this study, a three dimensional (2D and 3D) finite-volume-based models was developed for analyzing the heat transfer mechanisms through the porous structures of cellular concretes under steady-state heat transfer condition and also for investigating the differences between 2D and 3D modeling results. 2D and 3D reconstructed pore networks were generated from the microstructural information measured by a 3D image captured by X-ray computerized tomography (X-CT). In addition, the 3D-computed value of the effective thermal conductivity was found to be in better agreement …
Influence Of Controlled Permeability Formwork On The Permeability Of Concrete, Wei Lin, Q. Jiang, J. Liu, J. Liu
Influence Of Controlled Permeability Formwork On The Permeability Of Concrete, Wei Lin, Q. Jiang, J. Liu, J. Liu
International Conference on Durability of Concrete Structures
Corrosion of steel reinforcement related to the intrusion of chloride ion is still the main threats to the durability of concrete structure, especially in marine environment. For the purpose of delaying the Cl− concentration at the surface of steel reinforcement reaching the critical value leading to initial corrosion, the permeability of concrete is usually improved by optimizing the concrete mixture to achieve high compatibility as well as optimized pore structure. In recent years, controlled permeability formwork (CPF) which was originally developed to obtain much smoother surface of the concrete proves to promote the service performance of the concrete by …
The Correlation Of Chloride Diffusion Coefficient And Concrete Maturity Value And Its Application In Hong Kong–Zhuhai–Macao Bridge Engineering, Pengping Li, Shengnian Wang, Jianbo Xiong, Rui Chai, Yu Yan
The Correlation Of Chloride Diffusion Coefficient And Concrete Maturity Value And Its Application In Hong Kong–Zhuhai–Macao Bridge Engineering, Pengping Li, Shengnian Wang, Jianbo Xiong, Rui Chai, Yu Yan
International Conference on Durability of Concrete Structures
The correlation of chloride diffusion coefficient and concrete maturity value within 56 days of curing was investigated by the chemically combined water content method, rapid chloride migration (RCM) test, and concrete maturity test. The experimental results showed that chloride diffusion coefficient of concretes decreased not only with increasing curing ages but also with increasing curing temperature, which can promote the hydration degree of cementitous materials. There is a significant correlation between the chloride diffusion coefficient of indoor cured specimens and the concrete maturity value when expressed as a power function (R2 = 0.976). In addition, the calculated values of …
Characterizing The Pore Structure Of Carbonated Natural Wollastonite, Chiara Villani, Robert Spragg, Raikhan Tokpatayeva, Jan Olek, W. Jason Weiss
Characterizing The Pore Structure Of Carbonated Natural Wollastonite, Chiara Villani, Robert Spragg, Raikhan Tokpatayeva, Jan Olek, W. Jason Weiss
International Conference on Durability of Concrete Structures
This paper focuses on examining the pore structure of a cementitious paste made with a calcium silicate (wollastonite) that reacts with carbon dioxide and water to form a hardened solid. The pore structure of the hardened solid has been characterized using vapor sorption and desorption, low-temperature differential scanning calorimetry (LT-DSC), and scanning electron microscopy (SEM). The total porosity was also measured using mass measurement in oven-dry and vacuum-saturated conditions. Evidence exists that support the hypothesis that the solid has two main pore sizes: large macropores (>10 nm) appear to form between the initial calcium silicate particles and small micropores …
Analysis Of The Influence Of Organic Corrosion Inhibitors On Corrosion Of Reinforcement In Concrete Bridge Structure Under Simulated Field Service Environment, Liang Shi, J. Ye, C. C. Chen, Y. Wu, J. Z. Liu
Analysis Of The Influence Of Organic Corrosion Inhibitors On Corrosion Of Reinforcement In Concrete Bridge Structure Under Simulated Field Service Environment, Liang Shi, J. Ye, C. C. Chen, Y. Wu, J. Z. Liu
International Conference on Durability of Concrete Structures
For concrete bridge projects in marine environments, attention must be paid to the reinforcement corrosion problems caused by chloride intrusion. As kinds of functional admixtures, which can reduce the reinforcement corrosion rate, corrosion inhibitors are becoming very popular in China in new bridge projects. Corrosion inhibitors cover both inorganic and organic inhibitors. Nitrite is representative of inorganic corrosion inhibitors, but its carcinogenicity has hindered its further development. Organic corrosion inhibitors such as small-molecule-based alcohol amine series are becoming the focus of attention. To guide the scientific applications of organic corrosion inhibitors, China is carrying out broad applications technology research. But …
Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss
Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss
International Conference on Durability of Concrete Structures
The use of superabsorbent polymers (SAPs) to produce internally cured concrete has been shown to be effective in reducing the potential for restrained shrinkage cracking of high performance concrete mixtures. However, not much is known regarding the freeze–thaw durability of concrete mixtures that incorporate SAPs for internal curing (IC). When SAP particles desorb (or partially desorb) the “water” (pore fluid) they contain for the purposes of IC, some believe that the void space created by these particles can provide enough empty voids to accommodate the additional volume caused by water expansion upon freezing. This paper investigates the freeze–thaw durability of …
Influence Of Organic Inhibitor On Corrosion Resistance Of Steel In Simulated Concrete Pore Solution, Jingshun S. Cai, C. C. Chen, J. Z. Liu, J. P. Liu
Influence Of Organic Inhibitor On Corrosion Resistance Of Steel In Simulated Concrete Pore Solution, Jingshun S. Cai, C. C. Chen, J. Z. Liu, J. P. Liu
International Conference on Durability of Concrete Structures
Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with the concentration of inhibitor increase; when the content of inhibitor up to 1.5% versus water, the oxide film was completely passive. Organic corrosion inhibitor had no effect on work performance.
Co2 Sequestration In Cement-Based Materials During Mixing Process Using Carbonated Water And Gaseous Co2, Jacek Kwasny, P. A. Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward
Co2 Sequestration In Cement-Based Materials During Mixing Process Using Carbonated Water And Gaseous Co2, Jacek Kwasny, P. A. Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward
International Conference on Durability of Concrete Structures
This paper presents selected findings from a recently completed research project, aimed at the investigation of CO2 sequestration in cement-based materials during the early stages of hydration when the cement paste is being mixed. Portland cement pastes were carbonated during the mixing process, using both carbonated water and gaseous CO2, and their properties were compared to the control non-carbonated mix. All mixes were prepared in a purpose-designed chamber that permitted carbonated water and gaseous CO2 to be mixed with the cementbased materials during the mixing process, without losses of CO2 to the external environment. Temperature …