期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
Surface Modification of Fly Ashes with Carbide Slag and Its Effect on Compressive Strength and Autogenous Shrinkage of Blended Cement Pastes 被引量:16
1
作者 郝成伟 邓敏 +1 位作者 MO Liwu LIU Kaiwei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第6期1149-1153,共5页
Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were charact... Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Effect of surface-modified fly ashes on compressive strength and autogenous shrinkage of blended cement pastes was investigated. Microstructures of cement pastes were examined by backscattered electron (BSE) imaging and mercury intrusion porosimetry (MIP). The experimental results showed that β-C2S was formed on the surfaces of fly ashes after modification. Hydration ofβ-C2S on the surface-modified fly ashes densified interface zone and enhanced bond strength between particles of fly ashes and hydrated clinkers. In addition, surface modification of fly ashes tended to decrease total porosity and 10-50 nm pores of cement pastes. Surface modification of fly ashes increased compressive strength and reduced autogenous shrinkage of cement pastes. 展开更多
关键词 surface modification fly ash carbide slag autogenous shrinkage compressive strength
下载PDF
Effect of Pre-wetted Light-weight Aggregate on Internal RelativeHumidity and Autogenous Shrinkage of Concrete 被引量:3
2
作者 叶家军 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第1期134-137,共4页
This research indicates that the gradient of internal relative humidity (IRH) decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of ... This research indicates that the gradient of internal relative humidity (IRH) decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of concrete. By importing a proper amount of water, the process of the decline of IRH can be delayed and the autogenous shrinkage can be reduced. The relationship among the amount of water imported by pre- wetted lightweight aggregate, IRH and AS was established. The result provides a new method of reducing early AS and enhancing early cracking resistance of HPC. 展开更多
关键词 autogenous shrinkage pre-wetted lightweight aggregate internal relative humidity high performance concrete
下载PDF
Autogenous Shrinkage of High Strength Lightweight Aggregate Concrete 被引量:2
3
作者 丁庆军 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2005年第4期123-125,共3页
The characteristic of autogenous shrinkage(AS) and its effect on high strength lightweight aggregate concrete(HSLAC) were studied.The experimental results show that the main shrinkage of high strength concrete is ... The characteristic of autogenous shrinkage(AS) and its effect on high strength lightweight aggregate concrete(HSLAC) were studied.The experimental results show that the main shrinkage of high strength concrete is AS and the amount of cement can affect the AS of HSLAC remarkably,At the early stage the AS of HSLAC is lower than that of high strength normal concrete,but it has a large growth at the later stage.The AS of high strength normal concrete becomes stable at 90d age,but HSLAC still has a high AS growth .It is found that adjusting the volume rate of lightweight aggregate,mixing with a proper dosage of fly ash and raising the water saturation degree of lightweight aggregate can markedly reduce the AS rate of HSLAC. 展开更多
关键词 high strength lightweight aggregate concrete autogenous shrinkage lightweight aggregate volume rate
下载PDF
Mesocosmic study on autogenous shrinkage of concrete with consideration of effects of temperature and humidity 被引量:1
4
作者 Yan HAI Yue-ming ZHU 《Water Science and Engineering》 EI CAS 2009年第4期85-94,共10页
A study on the autogenous shrinkage (AS) of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity (ARH), two fac... A study on the autogenous shrinkage (AS) of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity (ARH), two factors that have been shown to have occasional influence on this process in previous studies, were introduced into this study. According to these concepts, a program for simulation of the temperature field, humidity field, and stress field based on the equivalent age method and a fully automatic aggregate modeling tool were used. With the help of these programs, the study of a small concrete specimen provided some useful conclusions: the aggregate and the matrix show distinct distribution properties in the temperature field, humidity field, and stress field; the aggregate-matrix interface has a high possibility of becoming the location of the initial cracking caused by AS of concrete; the distribution of random aggregates is extremely important for mesoscopical analysis; and the temperature history is the main factor affecting the AS of concrete. On the whole, inherent mechanisms and cracking mechanisms of AS of concrete can be explained more reasonably and realistically only by considering the different characteristics of material phases and the effects of temperature and humidity. 展开更多
关键词 CONCRETE autogenous shrinkage meso-analysis equivalent age temperature history autogenous relative humidity
下载PDF
Experimental Research on the Autogenous Shrinkage of MK High Performance Concrete
5
作者 王宝民 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第3期551-554,共4页
Calcine and mill kaolin were used under agreeable technological conditions to generate matakaolin (MK). The autogenous shrinkage performance of high performance concrete added with MK was researched. It is shown tha... Calcine and mill kaolin were used under agreeable technological conditions to generate matakaolin (MK). The autogenous shrinkage performance of high performance concrete added with MK was researched. It is shown that MK has an effective inhibitory action to early autogenous shrinkage of cement concrete, and the inhibitory action increases with the increase of MK. The autogenous shrinkage values from 24 hours after placement to 56 days are all higher than those of the contrasted concrete, among which, the value of the concrete with 5% MK is the highest. But the total shrinkage values in 56 days are all less than those of the contrasted test pieces. The total contraction after 24 h of placement decreases as the increase of MK, moreover, it is greatly less than that of the contrasted ones. 展开更多
关键词 high performance concrete MK autogenous shrinkage
下载PDF
Characterisation of Early Age Deformations in Cement Paste: Case of Chemical and Autogenous Shrinkage
6
作者 Nkwenti Flavious Tanue Tubuo Fabian +1 位作者 Fokwa Didier Tchemou Gilbert 《Journal of Minerals and Materials Characterization and Engineering》 2020年第4期223-239,共17页
Concrete is commonly seen as a durable and long-lasting construction material. However, the long-term performance of a concrete structure can be greatly compromised by early-age cracking. This work is an experimental ... Concrete is commonly seen as a durable and long-lasting construction material. However, the long-term performance of a concrete structure can be greatly compromised by early-age cracking. This work is an experimental contribution to study early age deformations of cement paste. Its aim is, firstly, to develop an experimental dispositive for assessing chemical and autogenous shrinkage, and secondly, to measure these volumetric deformations in cement paste. The setup was done following the gravimetric method of measurement, which exploits the Archimedes’ principle. It is made up of an electronic balance, a data accusation unit, a temperature control unit and a buoyancy bath. Investigations were done on Portland cement (CPA-CEM II) at the following W/C ratios: 0.25, 0.3, 0.35, 0.4 and 0.5. It was noticed that the water-cement ratio does not influence the magnitude of the chemical shrinkage in a significant manner but had a kinetic effect;a lower W/C induces a faster rate of chemical shrinkage. Autogenous shrinkage was discovered to be highly inversely proportional to the W/C and was also noticed to be in a function of chemical shrinkage within the first 2 to 4 hours when the paste was still liquid. 展开更多
关键词 autogenous shrinkage Chemical shrinkage Volumetric Deformation Water-Cement Ratio
下载PDF
Hydration, microstructure and autogenous shrinkage behaviors of cement mortars by addition of superabsorbent polymers 被引量:4
7
作者 Beibei SUN Hao WU +2 位作者 Weimin SONG Zhe LI Jia YU 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2020年第5期1274-1284,共11页
Superabsorbent Polymer(SAP)has emerged as a topic of considerable interest in recent years.The present study systematically and quantitively investigated the effect of SAP on hydration,autogenous shrinkage,mechanical ... Superabsorbent Polymer(SAP)has emerged as a topic of considerable interest in recent years.The present study systematically and quantitively investigated the effect of SAP on hydration,autogenous shrinkage,mechanical properties,and microstructure of cement mortars.Influences of SAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test method.Scanning Electron Microscope(SEM)was employed to assess the microstructure evolution.Although SAP decreased the peak rate of hydration heat and retarded the hydration,it significantly increased the cumulative heat,indicating SAP helps promote the hydration.Hydration promotion caused by SAP mainly occurred in the deceleration period and attenuation period.SAP can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%.Microstructure characteristics showed that pores and gaps were introduced when SAP was added.The microstructure difference caused by SAP contributed to the inferior mechanical behaviors of cement mortars treated by SAP. 展开更多
关键词 Superabsorbent Polymer mechanical properties hydration heat autogenous shrinkage MICROSTRUCTURE
原文传递
Early-Age Properties Development of Recycled Glass Powder Blended Cement Paste:Strengths,Shrinkage,Nanoscale Characteristics,and Environmental Analysis
8
作者 Zhihai He Menglu Shen +3 位作者 Jinyan Shi Jingyu Chang Víctor Revilla-Cuesta Osman Gencel 《Journal of Renewable Materials》 SCIE EI 2023年第4期1835-1852,共18页
Recycling solid waste in cement-based materials cannot only ease its load on the natural environment but also reduce the carbon emissions of building materials.This study aims to investigate the effect of recycled gla... Recycling solid waste in cement-based materials cannot only ease its load on the natural environment but also reduce the carbon emissions of building materials.This study aims to investigate the effect of recycled glass powder(RGP)on the early-age mechanical properties and autogenous shrinkage of cement pastes,where cement is replaced by 10%,20%and 30%of RGP.In addition,the microstructure and nano-mechanical properties of cement paste with different RGP content and water to binder(W/B)ratio were also evaluated using SEM,MIP and nanoindentation techniques.The results indicate that the early-age autogenous shrinkage decreases with the increase of RGP content and W/B ratio.While the mechanical strength deteriorates due to the addition of RGP,it can be compensated by reducing the W/B ratio.Although the addition of RGP increases the total porosity of the hardened paste,it reduces the small size porosity(<50 nm).In addition,the proportions of different types of C-S-H are changed,and the volume fraction of porosity is increased,but that of hydration products of cement paste is reduced due to the incorporation of RGP.Besides its pozzolanic activity,the mitigated shrinkage deformation that RGP is generating in cement pastes is encouraging for its use as a novel supplementary cementitious material that reduces the early-age cracking risk of cement-based materials.Meanwhile,the life cycle assessments indicate that the RGP-cement component is an economical and eco-friendly novel engineering material. 展开更多
关键词 Cement paste waste glass powder autogenous shrinkage microstructure NANOINDENTATION
下载PDF
An Investigation into the Performances of Cement Mortar Incorporating Superabsorbent Polymer Synthesized with Kaolin
9
作者 Xiao Huang Jin Yang 《Fluid Dynamics & Materials Processing》 EI 2024年第6期1393-1406,共14页
Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to i... Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties.This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers(K-SAP)on the properties of cement mortar.The results show that K-SAP significantly affects the cement mortar’s rheological behavior,with distinct phases of water absorption and release,leading to changes in workability over time.Furthermore,K-SAP alters the hydration kinetics,delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics.Notably,K-SAP effectively maintains a higher internal relative humidity within the mortar,reducing the autogenous shrinkage behavior.Moreover,K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP. 展开更多
关键词 Superabsorbent polymer KAOLIN cement mortar rheological behavior autogenous shrinkage
下载PDF
Self-desiccation mechanism of high-performance concrete 被引量:1
10
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
下载PDF
Influence of Repeated Variable Load on Long-Term Behavior of Concrete Elements 被引量:1
11
作者 Toni Arangjelovski GoranMarkovski Peter Mark 《Journal of Civil Engineering and Architecture》 2014年第3期302-314,共13页
The objective of this paper is to study the influence of repeated variable action on long-term behavior of concrete structural elements using quasi-permanent combination of actions, for the assessment of long-term eff... The objective of this paper is to study the influence of repeated variable action on long-term behavior of concrete structural elements using quasi-permanent combination of actions, for the assessment of long-term effects (e.g., effects due to creep and shrinkage in concrete structures), as it is proposed in Eurocodes. Extensive experimental program and analytical research using model B3 and AAEM (age adjusted effective modulus) method was performed in order to define quasi-permanent factor ψ2, for two specific loading histories. These loading histories were consist of long-term permanent action "G" and repeated variable action "Q". The variable load was applied in cycles of loading/unloading for 24 h and 48 h in period of 400 days appropriately for one series of concrete elements. 24 reinforced concrete beams, dimensions 150 mm × 280 mm × 3,000 mm, were tested. Twelve beams were made of concrete class C30/37 and 12 of concrete class C60/75. 展开更多
关键词 Repeated variable actions autogenous shrinkage CREEP Model B3.
下载PDF
Experimental Research on Early-Age Property of High-Performance Concrete Column by Embedded Sensors
12
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
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部