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Expansion Performance and Microstructure of High-performance Concrete using Differently Scaled MgO Agents and Mineral Powder
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作者 TIAN Changjin WANG Youzhi +1 位作者 QIU Kai YANG Qilin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1335-1347,共13页
To investigate the assumptions proposed in this paper,the evolution law governing the strength and expansion performance of MgO and nano-MgO micro-expansive concrete in the environment of mineral powder was firstly ob... To investigate the assumptions proposed in this paper,the evolution law governing the strength and expansion performance of MgO and nano-MgO micro-expansive concrete in the environment of mineral powder was firstly observed in this study.Secondly,SEM,XRD,and TG-DSC microscopic tests were conducted to reveal the effects of the active mineral-powder admixture on the hydration degree and expansion performance of MgO and nano-MgO in HPC.Our experimental results successfully verified our hypothesis,which indicated that the expansion performance of macro-MgO and nano-MgO was indeed depressed by the addition of active mineral power admixtures,even though the mechanical property of concrete composites was effectively improved.Furthermore,the hydration test also demonstrated the negative interference on the mineral powders,which was induced by the expansion agents.It is found the amounts of hydrates tend to decrease because the mineral powder ratio reaches and exceeds 40%.Moreover,it is also concluded the effect of expansion agents is governed by the alkalinity cement paste,especially for the nano-MgO.In other words,the expansion performance of nano-MgO will vary more obviously with the hydration process,than MgO.The results of this study provide that effective experimental and theoretical data support the hydration-inhibition mechanism of magnesium expansive agents. 展开更多
关键词 MGO Nano-MgO mineral powders high-performance concrete expansive agents MICROSTRUCTURES
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Measurement and analysis of defects in high-performance concrete with three-dimensional micro-computer tomography 被引量:8
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作者 郭丽萍 Andrea Carpinteri +1 位作者 孙伟 秦文超 《Journal of Southeast University(English Edition)》 EI CAS 2009年第1期83-88,共6页
In order to investigate the effects of two mineral admixtures (i. e., fly ash and ground slag)on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT( micro-focus computer tomogra... In order to investigate the effects of two mineral admixtures (i. e., fly ash and ground slag)on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT( micro-focus computer tomography)is employed to quantitatively analyze the initial defects in four series of highperformance concrete (HPC)specimens with additions of different mineral admixtures. The nigh-resolution 3D images of microstructures and filtered defects are reconstructed by micro- CT software. The size distribution and volume fractions of initial defects are analyzed based on 3D and 2D micro-CT images. The analysis results are verified by experimental results of watersuction tests. The results show that the additions of mineral admixtures in concrete as cementitious materials greatly change the geometrical properties of the microstructures and the spatial features of defects by physical-chemistry actions of these mineral admixtures. This is the major cause of the differences between the mechanical behaviors of HPC with and without mineral admixtures when the water-to-binder ratio and the size distribution of aggregates are constant. 展开更多
关键词 high-performance concrete DEFECT MICROSTRUCTURE X- ray micro-focus computer tomography mineral admixtures
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Comparative impact behaviours of ultra high performance concrete columns reinforced with polypropylene vs steel fibres
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作者 Thong M.Pham Harrison Hyde +4 位作者 Maw K.Kaung Yan Zhuge Duong T.Tran Des Vlietstra Tung M.Tran 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第10期138-153,共16页
Polypropylene(PP) fibres have primarily used to control shrinkage cracks or mitigate explosive spalling in concrete structures exposed to fire or subjected to impact/blast loads, with limited investigations on capacit... Polypropylene(PP) fibres have primarily used to control shrinkage cracks or mitigate explosive spalling in concrete structures exposed to fire or subjected to impact/blast loads, with limited investigations on capacity improvement. This study unveils the possibility of using PP micro-fibres to improve the impact behaviour of fibre-reinforced ultra-high-performance concrete(FRUHPC) columns. Results show that the addition of fibres significantly improves the impact behaviour of FRUHPC columns by shifting the failure mechanism from brittle shear to favourable flexural failure. The addition of steel or PP fibres affected the impact responses differently. Steel fibres considerably increased the peak impact force(up to 18%) while PP micro-fibres slightly increased the peak(3%-4%). FRUHPC significantly reduced the maximum midheight displacement by up to 30%(under 20°impact) and substantially improved the displacement recovery by up to 100%(under 20° impact). FRUHPC with steel fibres significantly improved the energy absorption while those with PP micro-fibres reduced the energy absorption, which is different from the effect of PP-macro fibre reported in the literature. The optimal fibre content for micro-PP fibres is 1% due to its minimal fibre usage and low peak and residual displacement. This study highlights the potential of FRUHPC as a promising material for impact-resistant structures by creating a more favourable flexural failure mechanism, enhancing ductility and toughness under impact loading, and advancing the understanding of the role of fibres in structural performance. 展开更多
关键词 Ultra high-performance concrete Steel fibre Polypropylene micro-fibre Fibre volume fraction Impact loading Pendulum tests COLUMNS
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Influence of shrinkage-reducing admixture on drying shrinkage and mechanical properties of high-performance concrete 被引量:5
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作者 Nguyen Quangphu Jiang Linhua +2 位作者 Liu Jiaping Tian Qian Do Tienquan 《Water Science and Engineering》 EI CAS 2008年第4期67-74,共8页
High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.... High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.2-0.4, so volume changes of concrete as a result of drying, chemical reactions, and temperature change cannot be avoided. For these reasons, shrinkage and cracking are frequent phenomena. It is necessary to add some types of admixture for reduction of shrinkage and cracking of HPC. This study used a shrinkage-reducing admixture (SRA) for that purpose. Concrete was prepared with two different mW/mB (0.22 and 0.40) and four different mass fractions of SRA to binder (w(SRA) = 0%, 1%, 2%, and 4%). The mineral admixtures used for concrete mixes were: 25% fly ash (FA) and 25% slag by mass of binder for the mixture with mW/mB = 0.40, and 15% silica fume (SF) and 25% FA for the mixture with mW/mB = 0.22. Tests were conducted on 24 prismatic specimens, and shrinkage strains were measured through 120 days of drying. Compressive strength, splitting strength, and static modulus of elasticity were also determined. The results show that the SRA effectively reduces some mechanical properties of HPC. The reductions in compressive strength, splitting tensile strength, and elastic modulus of the concrete were 7%-24%, 9%-19%, and 5%-12%, respectively, after 90 days, compared to concrete mixtures without SRA. SRA can also help reduce drying shrinkage of concrete. The shrinkage strains of HPC with SRA were only as high as 41% of the average free shrinkage of concrete without SRA after 120 days of drying. 展开更多
关键词 high-performance concrete shrinkage-reducing admixture compressive strength elastic modulus splitting tensile strength drying shrinkage
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INFLUENCE OF MINERAL ADMIXTURES ON MECHANICAL PROPERTIES OF HIGH-PERFORMANCE CONCRETE 被引量:4
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作者 Ma, Baoguo Li, Jinzong Peng, Jun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1999年第2期1-7,共7页
The improvements of the mechanical properties, including bulk density of fresh mixtures, elastic modulus, and compressive strengths of four high-performance concrete mixtures, made with the addition of fly ash, refine... The improvements of the mechanical properties, including bulk density of fresh mixtures, elastic modulus, and compressive strengths of four high-performance concrete mixtures, made with the addition of fly ash, refined ground blast - furnace microslag (microslag) and silica fume are studied. The concrete mixtures were determined based on the dispersion testing results. The study indicates that the elastic modulus at 28 and 91 days, and compressive strengths of the concretes are improved a lot when fly ash and microslag by 25 percent by weight of cement are added into the mixtures individually. The improvement is especially evident when silica fume by 5 percent and fly ash by 25 percent by weight of cement are added together into the mixture, while the fresh concrete mixture keeps a good workability. Through the analysis of chemically combined water ratios of the four mixtures at various hydration ages, it is found that the addition of all these mineral mixtures are beneficial to the hydration process, especially, at later stages, which might be one of the reasons for the improvement of mechanical properties. (Author abstract) 4 Refs. 展开更多
关键词 high-performance concrete mineral admixture mechanical properties
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Effects of submicron-MgO and nano-MgO on the expansion and microscopic properties of high-performance concrete 被引量:2
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作者 TIAN Chang-jin WANG You-zhi +1 位作者 QIU Kai YANG Qi-lin 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第9期3186-3200,共15页
MgO-series expansive agents can effectively compensate for the shrinkage and deformation of concrete structures.However,few experimental studies have been conducted on MgO expansive agents,particularly concerning the ... MgO-series expansive agents can effectively compensate for the shrinkage and deformation of concrete structures.However,few experimental studies have been conducted on MgO expansive agents,particularly concerning the difference between and effects of submicron-MgO and nano-MgO in high-performance concrete(HPC)with a low water-cement ratio,thereby limiting their application in practical engineering.To clarify the expansion effect and expansion mechanism of MgO expansive agents in HPC,the effects of submicron-MgO and nano-MgO on the strength,toughness,and expansion characteristics of HPC were examined.The test results showed that submicron-MgO and nano-MgO continued to hydrate in the cement environment to produce Mg(OH)_(2),thus improving the structural compactness and structural strength of HPC.Nano-MgO concrete was found to have more stable mechanical properties and better structural deformability than submicron-MgO concrete.This study provides effective data support and theoretical reference concerning the hydration expansion mechanisms and engineering applications of nano-expanded materials. 展开更多
关键词 submicron-MgO nano-MgO high-performance concrete STRENGTH TOUGHNESS expansion characteristics microstructure
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Spalling and Mechanical Properties of Fiber Reinforced High-performance Concrete Subjected to Fire 被引量:3
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作者 董香军 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第5期743-749,共7页
Spalling and mechanical properties of FRHPC subjected to fire were tested on notched beams. The results confirm that the internal vapor pressure is the leading reason for spalling of high-performance concrete (HPC).... Spalling and mechanical properties of FRHPC subjected to fire were tested on notched beams. The results confirm that the internal vapor pressure is the leading reason for spalling of high-performance concrete (HPC). At the same time, the temperature-increasing velocity and constrained conditions of concrete element also play significant roles in spalling. Steel fibers cannot reduce the risk of spalling, although they have obvious beneficial effects on the mechanical properties of concrete before and after exposure to fire. Polypropylene (PP) fibers are very useful in preventing HPC from spalling, however, they have negative effects on the strengths. By using hybrid fibers (steel fibers+PP fibers), both good anti-spalling performance and improved mechanical properties come true, which may provide necessary safe guarantee for the rescue work and structure repair after fire disaster. 展开更多
关键词 fiber reinforced high-performance concrete (FRHPC) FIRE SPALLING compressive strength flexural toughness
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Assessment of early-age cracking of high-performance concrete in restrained ring specimens 被引量:2
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作者 Quang-phu NGUYEN Lin-hua JIANG Qiao ZHU 《Water Science and Engineering》 EI CAS 2010年第1期113-120,共8页
High-performance concrete (HPC) is stronger and more durable than conventional concrete. However, shrinkage and shrinkage cracking are common phenomena in HPC, especially early-age cracking. This study assessed earl... High-performance concrete (HPC) is stronger and more durable than conventional concrete. However, shrinkage and shrinkage cracking are common phenomena in HPC, especially early-age cracking. This study assessed early-age cracking of HPC for two mixtures using restrained ring tests. The two mixtures were produced with water/binder mass ratio (mw/mB) of 0.22 and 0.40, respectively. The results show that, with greater steel thickness, the higher degree of restraint resulted in a higher interface pressure and earlier cracking. With steel thickness of 6 mm, 19 mm, and 30 mm, the age of cracking were, respectively, 12 days, 8 days, and 5.4 days with the mw/mB = 0.22 mixture; and 22.5 days, 12.6 days, and 7.1 days with the mw/mB= 0.40 mixture. Cases of the same steel thickness show that the ring specimens with a thicker concrete wall crack later. With the mw/mB = 0.22 mixture, concrete walls with thicknesses of 37.5 mm, 75 mm, and 112.5 mm cracked at 3.4 days, 8.0 days, and 9.8 days, respectively; with the mw/mB = 0.40 mixture, the ages of cracking were 7.1 days, 12.6 days, and 16.0 days, respectively. 展开更多
关键词 high-performance concrete SHRINKAGE early-age cracking restrained ring test
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Creep experimental test and analysis of high-performance concrete in bridge 被引量:1
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作者 陈志华 袁健 《Journal of Central South University》 SCIE EI CAS 2008年第S1期577-581,共5页
Factors that have effect on concrete creep include mixture composition,curing conditions,ambient exposure conditions,and element geometry.Considering concrete mixtures influence and in order to improve the prediction ... Factors that have effect on concrete creep include mixture composition,curing conditions,ambient exposure conditions,and element geometry.Considering concrete mixtures influence and in order to improve the prediction of prestress loss in important structures,an experimental test under laboratory conditions was carried out to investigate compression creep of two high performance concrete mixtures used for prestressed members in one bridge.Based on the experimental results,a power exponent function of creep degree for structural numerical analysis was used to model the creep degree of two HPCs,and two series of parameters of this function for two HPCs were calculated with evolution program optimum method.The experimental data was compared with CEB-FIP 90 and ACI 209(92) models,and the two code models both overestimated creep degrees of the two HPCs.So it is recommended that the power exponent function should be used in this bridge structure analysis. 展开更多
关键词 CEMENT concrete CREEP high-performance concrete(HPC)
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FAILURE MODE AND CONSTITUTIVE MODEL OF PLAIN HIGH-STRENGTH HIGH-PERFORMANCE CONCRETE UNDER BIAXIAL COMPRESSION AFTER EXPOSURE TO HIGH TEMPERATURES 被引量:2
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作者 Zhenjun He Yupu Song 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第2期149-159,共11页
An orthotropic constitutive relationship with temperature parameters for plain highstrength high-performance concrete (HSHPC) under biaxial compression is developed. It is based on the experiments performed for char... An orthotropic constitutive relationship with temperature parameters for plain highstrength high-performance concrete (HSHPC) under biaxial compression is developed. It is based on the experiments performed for characterizing the strength and deformation behavior at two strength levels of HSHPC at 7 different stress ratios including a=σs : σ3=0.00:-1,-0.20:-1,-0.30 : -1,-0.40:-1,-0.50:-1,-0.75:-1,-1.00:-1, after the exposure to normal and high temperatures of 20, 200, 300, 400, 500 and 600℃, and using a large static-dynamic true triaxial machine. The biaxial tests were performed on 100 mm×100 mm×100 mm cubic specimens, and friction-reducing pads were used consisting of three layers of plastic membrane with glycerine in-between for the compressive loading plane. Based on the experimental results, failure modes of HSHPC specimens were described. The principal static compressive strengths, strains at the peak stress and stress-strain curves were measured; and the influence of the temperature and stress ratios on them was also analyzed. The experimental results showed that the uniaxial compressive strength of plain HSHPC after exposure to high temperatures does not decrease dramatically with the increase of temperature. The ratio of the biaxial to its uniaxial compressive strength depends on the stress ratios and brittleness-stiffness of HSHPC after exposure to different temperature levels. Comparison of the stress-strain results obtained from the theoretical model and the experimental data indicates good agreement. 展开更多
关键词 high-strength high-performance concrete (HSHPC) high temperatures uniaxial biaxial compressive strength failure criterion stress-strain relationship
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Self-desiccation mechanism of high-performance concrete 被引量:1
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作者 杨全兵 张树青 《Journal of Zhejiang University Science》 EI CSCD 2004年第12期1517-1523,共7页
Investigations on the effects of W/C ratio and silica fume on the autogenous shrinkage and internal relative humidity of high performance concrete (HPC), and analysis of the self-desiccation mechanisms of HPC showed t... Investigations on the effects of W/C ratio and silica fume on the autogenous shrinkage and internal relative humidity of high performance concrete (HPC), and analysis of the self-desiccation mechanisms of HPC showed that the autogenous shrinkage and internal relative humidity of HPC increases and decreases with the reduction of W/C respectively; and that these phenomena were amplified by the addition of silica fume. Theoretical analyses indicated that the reduction of RH in HPC was not due to shortage of water, but due to the fact that the evaporable water in HPC was not evaporated freely. The reduction of internal relative humidity or the so-called self-desiccation of HPC was chiefly caused by the increase in mole concentration of soluble ions in HPC and the reduction of pore size or the increase in the fraction of micro-pore water in the total evaporable water (Tr/Tte ratio). 展开更多
关键词 high-performance concrete Autogenous shrinkage SELF-DESICCATION Relative humidity
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Strength Regularity and Failure Criterion of High-Strength High-Performance Concrete under Multiaxial Compression 被引量:1
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作者 何振军 宋玉普 《Journal of Southwest Jiaotong University(English Edition)》 2008年第2期144-149,共6页
Multiaxial compression tests were performed on 100 mm×100 mm×100 mm high-strength high-performance concrete (HSI-IPC) cubes and normal strength concrete (NSC) cubes. The failure modes of specimens were p... Multiaxial compression tests were performed on 100 mm×100 mm×100 mm high-strength high-performance concrete (HSI-IPC) cubes and normal strength concrete (NSC) cubes. The failure modes of specimens were presented, the static compressive strengths in principal directions were measured, the influence of the stress ratios was analyzed. The experimental results show that the ultimate strengths for HSHPC and NSC under multiaxial compression are greater than the uniaxial compressive strengths at all stress ratios, and the multiaxial strength is dependent on the brittleness and stiffness of concrete, the stress state and the stress ratios. In addition, the Kupfer-Gersfle and Ottosen's failure criteria for plain HSHPC and NSC under multiaxial compressive loading were modified. 展开更多
关键词 High-strength high-performance concrete (HSHPC) Normal strength concrete (NSC) Stress ratio Multiaxial corn- pressive slxength Failure criterion
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Experimental study on creep of high-performance concretes
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作者 陈志华 马忠武 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第4期576-580,共5页
In order to investigate the compression creep of two kinds of high-performance concrete mixtures used for prestressed members in a bridge,an experimental test under laboratory conditions was carried out.Based on the e... In order to investigate the compression creep of two kinds of high-performance concrete mixtures used for prestressed members in a bridge,an experimental test under laboratory conditions was carried out.Based on the experimental results,a power exponent function was used to model the creep degree of these high-performance concretes(HPCs) for structural numerical analysis,and two series parameters of this function for the HPCs were given with the optimum method of evolution program.The experimental data were compared with CEB-FIP 90 and ACI 92 models.Results show that the two code models both overestimate the creep degree of two HPCs,so it is recommended that the power exponent function should be used for the creep analysis of bridge structure. 展开更多
关键词 CEMENT concrete CREEP high-performance concrete (HPC)
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Effects of fibers on mechanical properties of high-performance concrete subjected to elevated temperatures
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作者 董香军 丁一宁 曹凌坚 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第5期624-630,共7页
The compressive strength and ilexural toughness as well as fracture energy of fiber reinforced highperformance concrete (FRHPC) subjected to different high temperatures were studied. The results showed that after ex... The compressive strength and ilexural toughness as well as fracture energy of fiber reinforced highperformance concrete (FRHPC) subjected to different high temperatures were studied. The results showed that after exposure at 300,600 and 900℃, the concrete mixes retained 88.1% , 41.3% and 10.2% of the original compressive strength on average, respectively. Steel fiber and polypropylene (PP) fiber were both effective in minimizing the damage effect of high temperatures on the compressive strength. The HPC reinforced with steel fibers showed higher flexural toughness and fracture energy before and after the high-temperature exposures. In comparison, PP fibers had minor beneficial effects on the flexural toughness and fracture energy. The mechanical properties of HPC reinforced with hybrid fibers (steel fiber + PP fiber) were equivalent to or better than those of HPC reinforced with steel fibers alone. In addition, the failure pattern of FRHPC beams changed from pull-out of steel fibers at lower temperatures (20, 300 and 600℃) to tensile failure of steel fibers at higher temperature (900 ℃). 展开更多
关键词 fiber reinforced high-performance concrete FRHPC high temperature compressive strength flexural toughness failure pattern
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Experimental Research on Early-Age Property of High-Performance Concrete Column by Embedded Sensors
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作者 贠英伟 张晓玲 +1 位作者 何朋立 王帅 《Journal of Southwest Jiaotong University(English Edition)》 2008年第3期242-246,共5页
This paper aims at monitoring the autogenous shrinkage (AS) of a high-performance concrete (HPC) column specimen using an embedded strain gauge just after concrete pouring. A real size specimen (40 cm×40 cm&... This paper aims at monitoring the autogenous shrinkage (AS) of a high-performance concrete (HPC) column specimen using an embedded strain gauge just after concrete pouring. A real size specimen (40 cm×40 cm×100cm) was made to simulate the structural members in construction site. The results show that the amount of HPC AS is comparable to that of drying shrinkage and even larger than it, so AS can not be omitted for HPC. By comparing the plain HPC and reinforced HPC specimens, the influences of reinforced bars on autogenous shrinkage and temperature distribution were obtained. 展开更多
关键词 high-performance concrete Autogenous shrinkage Embedded strain gauge Temperature distribution
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INITIAL BINDING CAPACTIES OF CHLORIDE ION OF COMPONENTS IN HIGH-PERFORMANCE CONCRETE
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作者 马保国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1998年第4期16-24,共9页
An investigation is reported on the influence of different components of high performance concrete (HPC) on the initial binding capacities (IBC) of chloride ion. The testing results demonstrate that cement has the lar... An investigation is reported on the influence of different components of high performance concrete (HPC) on the initial binding capacities (IBC) of chloride ion. The testing results demonstrate that cement has the largest IBC, and the relative binding ratio is as high as 30% of total ion amount. Among the mineral admixtures, fly ash has the largest IBC of chloride ion. The IBC of silica fume is about 14.4%, which is smaller than that of fly ash. The IBC of refined ground blast-furnace slag (microslag) is abnormal due to the influence of sulfate ion contained. The addition of superplasticizer and corrosion inhibitor containing calcium nitrite weakens the IBC of mixtures. The fluidity and pore-filling effect of mineral admixtures are studied with paste samples with WIC ratio of 0.3. The influence mechanism of various components in high-performance concrete in IBC is studied further through SEM and Mercury Instrusion Porosimetry tests with paste samples at the age of 3 days. 展开更多
关键词 high-performance concrete super-plasticizer corrosion inhibitor initial binding capacity PERMEABILITY
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High-Performance and Multifunctional Cement-Based Composite Material 被引量:12
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作者 Victor C. Li 《Engineering》 SCIE EI 2019年第2期250-260,共11页
Concrete is a continuously evolving material, and even the definition of high-performance concrete has changed over time. In this paper, high-performance characteristics of concrete material are considered to be those... Concrete is a continuously evolving material, and even the definition of high-performance concrete has changed over time. In this paper, high-performance characteristics of concrete material are considered to be those that support the desirable durability, resilience, and sustainability of civil infrastructure that directly impact our quality of life. It is proposed that high-performance material characteristics include tensile ductility, autogenous crack-width control, and material “greenness.” Furthermore, smart functionalities should be aimed at enhancing infrastructure durability, resilience, and sustainability by responding to changes in the surrounding environment of the structure in order to perform desirable functions, thus causing the material to behave in a manner more akin to certain biological materials. Based on recent advances in engineered cementitious composites (ECCs), this paper suggests that concrete embodying such high-performance characteristics and smart multifunctionalities can be designed, and holds the potential to fulfill the expected civil infrastructure needs of the 21st century. Highlights of relevant properties of ECCs are provided, and directions for necessary future research are indicated. 展开更多
关键词 high-performance concrete MULTIFUNCTION Smart CEMENT-BASED composite Durability RESILIENCE Sustainability Infrastructure
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Properties and Microstructure of Marine Concrete with Composite Mineral Admixture 被引量:2
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作者 李方贤 陈友治 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第3期497-501,共5页
The influences of compositing mineral admixtures on the regularity of mechanical property, workability, durability and microstructure of C50 marine concrete were investigated. The results show that the incorporation o... The influences of compositing mineral admixtures on the regularity of mechanical property, workability, durability and microstructure of C50 marine concrete were investigated. The results show that the incorporation of mineral admixtures can improve the mechanical properties and workability of C50 marine concrete, 3 min-doped mineral admixture had excellent resistance to chloride ion permeability. The microscopic structure mixing mineral admixtures system was well-distributed and compact, little macroporeare can be found. 展开更多
关键词 high-performance concrete C50 marine concrete mineral admixture DURABILITY
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SULFATE RESISTANCE MECHANISM OF HIGH- PERFORMANCE CONCRETE CONTAINING NCI 被引量:2
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作者 MA Baoguo Wuhan University of Technology 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1999年第1期6-15,共10页
It is found that the incorporation of Nitrite Corrosion Inhibitor (NCI) greatly weakens the resistance of mixtures to sulfate attack. To study the mechanism of this phenomenon, in this paper, the influence of NCI add... It is found that the incorporation of Nitrite Corrosion Inhibitor (NCI) greatly weakens the resistance of mixtures to sulfate attack. To study the mechanism of this phenomenon, in this paper, the influence of NCI addition on the cement paste and microstructure change of high performance concrete specimens is studied by means of quantitative XRD, SEM tests. The results demonstrate that the incorporation of NCI accelerates the formation of calcium hydroxide and ettringite crystals, and weakens the pore refinement effect caused by the secondary hydration reaction of fly ash and microsilica. At the age up to one year, the relative crystal quantity in mixture containing NCI is always higher than that in control mixture. The reasons for the degradation in sulfate resistance of mixtures may be attributed to the increase and stability of the calcium hydroxide and ettringite crystals formed and the weakening of secondary hydration reaction. Based on the results, conclusion can be drawn that NCI should be used cautiously in practical engineering where high resistance to sulfate attack is required. (Author abstract) 7 Refs. 展开更多
关键词 nitrite corrosion inhibitor high-performance concrete MICROSTRUCTURE sulfate resistance
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基于淠河总干渠混凝土渡槽充水试验的变形监测
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作者 包善文 《工程建设与设计》 2024年第13期104-106,共3页
渡槽充水试验是保证正常通水前的试通水,要求对结构的安全性、稳定性及充水效果等进行全面的检查,同时对设计理念进行初步验证,目的是确保渡槽运行安全。论文以淠河总干渠混凝土渡槽充水试验为例,对渡槽的挠度变形和沉降观测方法进行了... 渡槽充水试验是保证正常通水前的试通水,要求对结构的安全性、稳定性及充水效果等进行全面的检查,同时对设计理念进行初步验证,目的是确保渡槽运行安全。论文以淠河总干渠混凝土渡槽充水试验为例,对渡槽的挠度变形和沉降观测方法进行了初步探索,并根据项目实际情况,提出了针对性的适用变形监测方案,同时进行了误差和精度分析。结果表明,此方案克服了各种不利条件的限制,同时,满足渡槽充水试验监测的精度要求。 展开更多
关键词 混凝土渡槽 充水试验 变形监测 跨中挠度
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