SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages最新文献

Detecting Solidification Using Moisture Transport from Saturated Lightweight Aggregate 利用饱和轻骨料的水分输送检测凝固

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56538

R. Henkensiefken, G. Sant, T. Nantung, J. Weiss

{"title":"Detecting Solidification Using Moisture Transport from Saturated Lightweight Aggregate","authors":"R. Henkensiefken, G. Sant, T. Nantung, J. Weiss","doi":"10.14359/56538","DOIUrl":"https://doi.org/10.14359/56538","url":null,"abstract":"This paper describes how the propensity for early-age shrinkage cracking in low water cement (w/c) concretes has spawned the development of new technologies that can reduce the risk of cracking. One such technology is internal curing. Internal curing uses saturated lightweight aggregate to supply ‘curing water’ to low w/c paste as it hydrates. Significant research has been performed to determine the effects of internal curing on shrinkage and stress development in sealed samples. However, relatively little detailed information exist about how water is released from the lightweight aggregate to the surrounding cement paste. This study examines the timing of moisture release from saturated lightweight aggregate (LWA). Specifically this paper focuses on fluid transport around the time of set. X-ray absorption is used to trace the time at which water moves from the lightweight aggregate to the paste. X-ray observations are compared with results from the Vicat needle, autogenous shrinkage, and acoustic emission tests. These results are contextualized in terms of structure formation and vapor space cavitation in the cement paste.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125180713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Flocculation Behavior of Cement Pastes Containing Clays and Fly Ash 含粘土和粉煤灰水泥浆体的絮凝性能

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56542

N. Tregger, H. Knai, Surendra P. Shah

引用次数: 3

Continuous Ultrasonic Assessment of Elastic Modulus of Cementitious Materials through Setting and Early Strength Gain 胶凝材料弹性模量与早期强度增益的连续超声评价

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56535

K. Subramaniam, Jaejun Lee

{"title":"Continuous Ultrasonic Assessment of Elastic Modulus of Cementitious Materials through Setting and Early Strength Gain","authors":"K. Subramaniam, Jaejun Lee","doi":"10.14359/56535","DOIUrl":"https://doi.org/10.14359/56535","url":null,"abstract":"This paper presents an ultrasonic method for continuously assessing changes in the shear modulus of hydrating cementitious materials after casting, through setting and early strength gain. In the test method, reflected shear waves from the interface between the material of the form and the cementitious material are monitored. The test procedure for obtaining the ultrasonic test data and the inversion subroutines for assessing the shear modulus of the cementitious material at different stages of hydration are described. Results from a test program showing the response of ultrasonic signals of 1 MHz frequency reflected from the interface between the form and mortar are presented. A form made of polymethyl-methacrylate (PMMA), was used in the study. The observed experimental trends are explained considering reflection at the interface between two visco-elastic materials. It is shown that shear modulus can be determined immediately after casting and the increase in shear modulus can be sensitively monitored through setting and early strength gain. The shear modulus assessed at 1 MHz exhibits a five orders of magnitude increase in the first 24 hours after casting. The rate of increase in the shear modulus is the most rapid before initial set. The rate of modulus decreases steadily through final set and early strength gain. It is shown that there is a complete phase reversal in the reflected waves with time. The reversal corresponds in time with the final setting time determined using ASTM C 403 and it occurs when the shear modulus of the mortar is almost equal to the shear modulus of PMMA.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123401801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Early Age Properties Development of Concrete with Different Slag Contents 不同矿渣掺量混凝土早期性能的发展

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56536

A. Darquennes, S. Staquet, A. Kamen, M. Delplancke-Ogletree, B. Espion

{"title":"Early Age Properties Development of Concrete with Different Slag Contents","authors":"A. Darquennes, S. Staquet, A. Kamen, M. Delplancke-Ogletree, B. Espion","doi":"10.14359/56536","DOIUrl":"https://doi.org/10.14359/56536","url":null,"abstract":"This paper describes how slag cement concrete is characterized with many advantages, which leads to its intensive use in the construction industry in Belgium. However, it may exhibit a high sensitivity to cracking at early age in case of restrained shrinkage. The understanding of this behavior involves an in-depth analysis of the early age deformations. First, an experimental investigation of the mechanical properties (compression strength, elastic modulus) and the microstructure evolution (hydration kinetic and hydrates development) was performed on three concretes containing different slag proportions (0%, 42% and 71% of the mass of binder), but with identical total binder content, in order to understand the effect of slag on these parameters. Second, the autogenous deformations were measured from casting time on concrete cylinders under isothermal conditions. The apparent activation energy and the time of initial set were also evaluated in order to analyze these deformations. The apparent activation energy is used to convert the actual age into equivalent age to express the concrete properties independently of the temperature variations. The time of initial set from which the strains are expressed is determined by ultrasonic detection and by the Kelly-Bryant method.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131340802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Identifying the Fluid-to-Solid Transition in Cementitious Materials at Early Ages Using Ultrasonic Wave Velocity and Computer Simulation 利用超声波速和计算机模拟识别胶凝材料早期的流固转变

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56537

Mukul Dehadrai, G. Sant, D. Bentz, J. Weiss

{"title":"Identifying the Fluid-to-Solid Transition in Cementitious Materials at Early Ages Using Ultrasonic Wave Velocity and Computer Simulation","authors":"Mukul Dehadrai, G. Sant, D. Bentz, J. Weiss","doi":"10.14359/56537","DOIUrl":"https://doi.org/10.14359/56537","url":null,"abstract":"This paper assesses that the fluid-to-solid transition in cementitious systems at early-ages is crucial for scheduling construction operations, for determining when laboratory testing can begin, and for assessing when computer simulations of restrained stress development should be initiated. This transition has been traditionally assessed using mechanical penetration techniques, which, though easy to perform, do not directly relate to the evolution of fundamental material properties or the microstructure. This paper assesses the fluid-to-solid transition of a cementitious material at early ages using measures that relate to the formation of a solid-skeleton in the material. The increase in the ultrasonic wave velocity is correlated to the percolation of a solid structure that occurs during the fluid-to-solid transition. The results of computer modeling (using CEMHYD3D) indicate that solidification as determined from the percolation of the solids is similar to experimental observations (Vicat test). It is noted that the rate of change in the pulse velocity is not a rigorous method for assessment of the time of solidification, especially in systems containing air. Rather, an increase in the pulse velocity beyond a threshold value appears to be a more appropriate method to assess structure formation. Further, the isothermal calorimetry (heat release) response is observed to not correspond to a fundamental aspect related to solid percolation or structure formation in the material.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131954817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Experimental Study on Restrained Drying Shrinkage Cracking of Concrete Using Acoustic Emission 声发射抑制混凝土干缩开裂试验研究

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56534

M. Ozawa, S. Uchida, T. Kamada, H. Morimoto

引用次数: 0

Simulation of Volume Changes of Cement Paste at Early Age 水泥浆体早期体积变化的模拟

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56544

I. Jaouadi, A. Guidoum, K. Scrivener

{"title":"Simulation of Volume Changes of Cement Paste at Early Age","authors":"I. Jaouadi, A. Guidoum, K. Scrivener","doi":"10.14359/56544","DOIUrl":"https://doi.org/10.14359/56544","url":null,"abstract":"The evolution of early age mechanical properties and volume change of cement paste is performed through Finite Element analysis on a 3D computer-generated cement paste. The time evolution of the hydrating microstructure is generated by μic(mike), a vectorial hydration model which takes into account the Particle Size Distribution (PSD) of anhydrous cement particles, the w/c ratio, the filler content and different hydration kinetics mechanisms such as nucleation, growth and diffusion. The microstructure geometry is then discretized into a finite element mesh. At each hydration step, the capillary depression is computed according to Laplace-Kelvin equation and applied on the pore space generated by the hydration model. Then, the autogenous shrinkage corresponds to the overall load-free deformation of the computational volume. Two constitutive models are used. The first one is a purely elastic model where macroscopic stress depends on the total porosity only. The second one is a poroelastic model which takes into account the fluid-solid interaction and the de-saturation effect. In parallel to the modeling work, a systematic experimental study has been performed on series of white cement pastes prepared different finenesses and various water-cement ratios. Many characterization techniques were used in the experimental study: chemical shrinkage, evolution of relative humidity, mercury intrusion porosimetry (MIP), x-ray diffraction (XRD), linear and volumetric autogenous shrinkage and ultrasonic wave propagation measurements. The numerical results are compared with experiment data and it is shown that the poroelastic model provides the best agreement to the experimental results. The remaining gap between the modeling and the experiment is discussed and future developments are outlined.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131918697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of a Quick Heat Generation Index Test for Characterization of Cementitious Materials 胶凝材料表征的快速热生成指数试验的评价

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56539

T. Rupnow, V. Schaefer, Kejin Wang

引用次数: 4

Early Age Stiffening of Cement Paste Using Ultrasonic Wave Reflection 超声反射法在水泥浆体早期加固中的应用

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56533

C. Chung, J. Popovics, L. Struble

{"title":"Early Age Stiffening of Cement Paste Using Ultrasonic Wave Reflection","authors":"C. Chung, J. Popovics, L. Struble","doi":"10.14359/56533","DOIUrl":"https://doi.org/10.14359/56533","url":null,"abstract":"This paper describes how ultrasonic wave reflection (UWR) has been used to monitor hydration and strength development of concrete. UWR measures the changes in reflected ultrasonic waves at the interface between a buffer material and hydrating cement paste. To monitor the subtle changes during early hydration it is necessary to use a buffer with low acoustic impedance, close to that of cement paste. In this research, UWR measurements on hydrating Type I portland cement are performed using a high impact polystyrene (HIPS) buffer. Both S-waves and P-waves are analyzed simultaneously to develop and extend the use of UWR to monitor early stiffening of cement paste. The penetration resistance test (ASTM C 403) and temperature rise of cement paste are used to correlate stiffening characteristics. The UWR responses show good correlation with results from temperature rise and penetration resistance. The onset of stiffening is the same for penetration resistance and both P- and S-wave UWR, and nearly the same for temperature rise. It is found that the HIPS buffer can provide sensitive measurement on the early age stiffening of cement paste.","PeriodicalId":306683,"journal":{"name":"SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130627173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Monitoring the Liquid to Solid Transition in Concrete with Conventional Tests 用常规试验监测混凝土的液固过渡

SP-259: Transition from Fluid to Solid: Re-Examining the Behavior of Concrete at Early Ages Pub Date : 2009-02-01 DOI: 10.14359/56543

J. Abel, R. Pinto, K. Hover

引用次数: 4