Advances in Research on Influence of Raw Materials on Workability of Fresh Concrete: A Review

2009 ◽  
Vol 405-406 ◽  
pp. 83-88 ◽  
Author(s):  
Gai Fei Peng ◽  
Zhan Qi Guo ◽  
Piet Stroeven ◽  
Ri Gao ◽  
Jiu Feng Zhang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Experimental Tests ◽  
Solid Particles ◽  
Future Research ◽  
Negative Effect ◽  
The Relationship ◽  
Positive Effect

A literature review was carried out to identify advances in research on workability of fresh concrete via both experimental tests and modeling, especially high performance concrete and self-compacting concrete. As to the relationship between fluidity of concrete and that of paste, future research can be conducted in two aspects, i.e. one is the influence of the quantity of paste in concrete, and another is the influence of fluidity of paste affected by a couple of factors. Most literature proved that the flow of concrete depends both on positive effect and negative effect, the former promote fluidity, such as dispersing, filling and lubricating, and the latter restricts fluidity, such as formation of particle coagulation, an increase of wettable surface of solid particles and mechanical interlock.

Advances in Research on Correlation of Workability and Rheology of Fresh Concrete: A Review

2009 ◽  
Vol 405-406 ◽  
pp. 77-82
Author(s):  
Gai Fei Peng ◽  
Zhan Qi Guo ◽  
Piet Stroeven ◽  
Ri Gao ◽  
Guang Hua Huang
Keyword(s):  
Literature Review ◽  
High Performance ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Experimental Tests ◽  
Test Method ◽  
Future Research ◽  
Specific Method ◽  
Self Compacting Concrete ◽  
The Relationship

A literature review was carried out to identify advances in research on workability of fresh concrete via both experimental tests and modeling, especially high performance concrete and self-compacting concrete. It is concluded that, in order to achieve better understanding of fresh concrete, especially self-compacting concrete (SCC) and high-performance concrete (HPC), a clear methodology of research should be established as the first step. It is suggested that there is no unique workability test method suitable for all the range of fluidity of fresh concrete, and a specific method should be identified for a proper range of fluidity. As to the relationship between fluidity of concrete and that of paste, future research can be conducted in two aspects, i.e. one is the influence of the quantity of paste in concrete, and another is the influence of fluidity of paste affected by a couple of factors.

scholarly journals Effect of Elevated Temperature on the Bond Strength of Prestressing Reinforcement in UHPC

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4990
Author(s):  
Petr Pokorný ◽  
Jiří Kolísko ◽  
David Čítek ◽  
Michaela Kostelecká
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Future Research ◽  
Ultra High Performance Concrete ◽  
Negative Effect ◽  
Laboratory Investigations ◽  
Increasing Temperature ◽  
Positive Effect

The study explores the effect of elevated temperatures on the bond strength between prestressing reinforcement and ultra-high performance concrete (UHPC). Laboratory investigations reveal that the changes in bond strength correspond well with the changes in compressive strength of UHPC and their correlation can be mathematically described. Exposition of specimens to temperatures up to 200 °C does not reduce bond strength as a negative effect of increasing temperature is outweighed by the positive effect of thermal increase on the reactivity of silica fume in UHPC mixture. Above 200 °C, bond strength significantly reduces; for instance, a decrease by about 70% is observed at 800 °C. The decreases in compressive and bond strengths for temperatures above 400 °C are related to the changes of phase composition of UHPC matrix (as revealed by X-ray powder diffraction) and the changes in microstructure including the increase of porosity (verified by mercury intrusion porosimetry and observation of confocal microscopy) and development cracks detected by scanning electron microscopy. Future research should investigate the effect of relaxation of prestressing reinforcement with increasing temperature on bond strength reduction by numerical modelling.

Mechanical Properties and Durability of Ultra-High Performance Concrete Incorporating Coarse Aggregate

2014 ◽  
Vol 629-630 ◽  
pp. 96-103 ◽  
Author(s):  
Juan Yang ◽  
Gai Fei Peng ◽  
Yu Xin Gao ◽  
Hui Zhang
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Autogenous Shrinkage ◽  
Mineral Admixtures ◽  
Ultra High Performance Concrete ◽  
Spalling Failure

Ultra-high performance concrete (UHPC) incorporating coarse aggregate was prepared with common raw materials. Fresh concrete had excellent good workability with slump of 265 mm and slump spread of 673 mm. Compressive strength of UHPC at 56 d reached 150 MPa. However, UHPC exhibited high brittleness in terms of spalling failure which occurred during compression loading.The ratio of splitting tensile strength to compressive strength of about 1/18 and the ratio of flexural strength to compressive strength of about 1/14 at 56 d were also associated with the brittleness of UHPC in this research. Mineral admixtures and fluidity of fresh concrete influenced compressive strength of UHPC significantly. Moreover, UHPC had excellent permeation-related durability but considerable shrinkage. Autogenous shrinkage of UHPC was less than half of free shrinkage, for which the reason is unknown and needs further research.

scholarly journals Materials for Production of High and Ultra-High Performance Concrete: Review and Perspective of Possible Novel Materials

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4304
Author(s):  
Markssuel Teixeira Marvila ◽  
Afonso Rangel Garcez de de Azevedo ◽  
Paulo R. de de Matos ◽  
Sergio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Review Article ◽  
Cement Matrix ◽  
Bibliographic Databases ◽  
Future Research ◽  
Chemical Additives ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Essential Components

This review article proposes the identification and basic concepts of materials that might be used for the production of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). Although other reviews have addressed this topic, the present work differs by presenting relevant aspects on possible materials applied in the production of HPC and UHPC. The main innovation of this review article is to identify the perspectives for new materials that can be considered in the production of novel special concretes. After consulting different bibliographic databases, some information related to ordinary Portland cement (OPC), mineral additions, aggregates, and chemical additives used for the production of HPC and UHPC were highlighted. Relevant information on the application of synthetic and natural fibers is also highlighted in association with a cement matrix of HPC and UHPC, forming composites with properties superior to conventional concrete used in civil construction. The article also presents some relevant characteristics for the application of HPC and UHPC produced with alkali-activated cement, an alternative binder to OPC produced through the reaction between two essential components: precursors and activators. Some information about the main types of precursors, subdivided into materials rich in aluminosilicates and rich in calcium, were also highlighted. Finally, suggestions for future work related to the application of HPC and UHPC are highlighted, guiding future research on this topic.

scholarly journals Comparative Study of High-Performance Concrete Characteristics and Loading Test of Pretensioned Experimental Beams

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 427
Author(s):  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Load Capacity ◽  
Materials Testing ◽  
Loading Test ◽  
Conventional Concrete ◽  
Concrete Mechanical Properties ◽  
Normal Strength

High-performance concrete (HPC) is subjected to wide attention in current research. Many research tasks are focused on laboratory testing of concrete mechanical properties with specific raw materials, where a mixture is prepared in a relatively small amount in ideal conditions. The wider utilization of HPC is connected, among other things, with its utilization in the construction industry. The paper presents two variants of HPC which were developed by modification of ordinary concrete used by a precast company for pretensioned bridge beams. The presented variants were produced in industrial conditions using common raw materials. Testing and comparison of basic mechanical properties are complemented with specialized tests of the resistance to chloride penetration. Tentative expenses for normal strength concrete (NSC) and HPC are compared. The research program was accomplished with a loading test of model experimental pretensioned beams with a length of 7 m made of ordinarily used concrete and one variant of HPC. The aim of the loading test was to determine the load–deformation diagrams and verify the design code load capacity calculation method. Overall, the article summarizes the possible benefits of using HPC compared to conventional concrete.

scholarly journals Effects of Self-Control on Subjective Well-Being: Examining the Moderating Role of Trait and State Motivation

2022 ◽  
Vol 12 ◽  
Author(s):  
Guojun Zhao ◽  
Fusen Xie ◽  
Yuchen Luo ◽  
Yixuan Liu ◽  
Yuan Chong ◽  
...  
Keyword(s):  
Well Being ◽  
Ego Depletion ◽  
Self Control ◽  
Future Research ◽  
Subjective Well Being ◽  
The Relationship ◽  
State Motivation ◽  
Positive Effect ◽  
Moderating Role

It is well documented that self-control has a positive effect on individuals’ subjective well-being. However, little research has focused on the moderators underlying this relationship. The present research used two studies to examine the moderating role of both trait and state motivation on the relationship between self-control and subjective well-being using psychometric and experimental models, respectively. In Study 1, we explored whether trait motivation (including promotion vs. prevention motivation) moderated the relationship between trait self-control and subjective well-being using a psychometric model. In Study 2, we examined the moderating effects of both trait and state motivation on the effect of state self-control (measured via ego depletion) on subjective well-being using an experimental model. Our results indicated that self-control had a positive effect on subjective well-being, with this relationship being primarily moderated by prevention motivation. When state and trait prevention motivations were congruent, self-control had the most obvious impact on subjective well-being. This study suggests that current understandings around the association between self-control and happiness is limited, implying that motivation should be the focus of future research.

scholarly journals PENGARUH RELATIONSHIP MARKETING DAN RELATIONSHIP QUALITY TERHADAP LOYALITAS PELANGGAN DENGAN KEPUASAN PELANGGAN SEBAGAI VARIABEL INTERVENING PADA PRODUK PARFUM MULEGH DI PURWOKERTO

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ilham Akbar
Keyword(s):  
Customer Satisfaction ◽  
Relationship Quality ◽  
Relationship Marketing ◽  
Customer Loyalty ◽  
Structural Equation ◽  
Marketing Relationship ◽  
Negative Effect ◽  
The Impact ◽  
The Relationship ◽  
Positive Effect

The research entitled �The Influence of Relationship Marketing and Relationship Quality Towards Customer Loyalty with Customer Satisfaction as The Intervening Variable on Mulleg Perfume Product in Purwokerto� aims to determine the impact of relationship marketing and relationship quality towards customer satisfaction and customer loyalty and to determine whether customer satisfaction could become the intervening variable. The hypothesis of this research is the relationship marketing has negative effect towards customer satisfaction, the relationship marketing has positive effect towards customer loyalty, the relationship quality has positively effect towards customer satisfaction, the relationship quality has positively effect towards the customer loyalty, and the customer loyalty could be able to mediate the influence of relationship marketing and relationship quality toward customer loyalty.� The analysis method that used on this research is the structural equation modeling.The results show that the relationship marketing has positive and significant effect towards customer satisfaction. It will increase the customer satisfaction of Mulleg Aromatic perfume product in Purwokerto. The relationship quality has positive and significant effect towards customer satisfaction, so it will increase the customer satisfaction of Mulleg Aromatic perfume product in Purwokerto. The relationship marketing has positive and significant effect towards customer loyalt. It will increase the customer loyalty of Mulleg Aromatic perfume product in Purwokerto. The relationship quality has positive and significant effect towards the customer loyalty. The Customer Satisfaction has positive and significant effect towards customer loyalty. The customer satisfaction could mediate the influence of relationship marketing towards the customer loyalty on Mulleg Aromatic perfume product in Purwokerto. The customer satisfaction could mediate the influence of relationship quality towards the customer loyalty of Mulleg Aromatic perfume product in Purwokerto.�Keywords : Relationship Marketing , Relationship Quality , Customer Satisfaction and Customer Loyalty�

scholarly journals How Does Group Climate Foster or Hinder Employee Voice? A Cross-Level Examination

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoye Qian ◽  
Qian Li ◽  
Jue Wang ◽  
Shiyang Gong ◽  
Hao Zhou
Keyword(s):  
Psychological Capital ◽  
Employee Voice ◽  
Full Time ◽  
Prevention Focus ◽  
Group Climate ◽  
Group Cooperation ◽  
Negative Effect ◽  
Using Data ◽  
The Relationship ◽  
Positive Effect

Although empirical evidence has accumulated showing that group climate has a significant impact on employee voice, knowledge about how different types of climates may influence voice is limited. Drawing upon the theory of planned behavior, we develop and test a model that explains whether and how the two group climates, cooperation and sanction, differentially predict employee promotive and prohibitive voice. We test the hypotheses using data collected from a sample of 274 full-time employees nested in 58 workgroups across two time periods. The empirical results show that group climate predicts employee voice in different ways: Group cooperation climate has a positive effect on both types of employee voice, whereas group sanction climate shows a negative effect on promotive voice. Individuals’ psychological capital is a cross-level mediator in the relationship between group climate and employee voice. Employees’ prevention focus negatively moderates the relationship between psychological capital and employee voice. These results highlight the important effect of group climate on employee voice in organization and calls on managers to create a favorable environment to increase employees’ psychological capital and voice behaviors.

Tongues, a Sign for Unbelievers?: A Structural and Exegetical Study of I Corinthians XIV. 20–25

1979 ◽  
Vol 25 (2) ◽  
pp. 180-203 ◽  
Author(s):  
B. C. Johanson
Keyword(s):  
The Other ◽  
Logical Relation ◽  
Other Hand ◽  
Positive Sense ◽  
Negative Effect ◽  
Relationship Of ◽  
The Relationship ◽  
Negative Sense ◽  
Positive Effect

I Corinthians xiv. 20–25 has long posed severalcruces interpretationisfor commentators. The basic problems concern the relationship of the assertions made about tongues and prophecy in υ. 22 to the quotation of Isa. xxviii. 11–12 in υ. 21 and to the illustrations concerning tongues and prophecy in υυ. 23–5. As to the quotation, J. Ruef remarks that most commentators admit to the difficulty of seeing how it substantiates Paul's conclusion that tongues are meant as a sign for the unbeliever. Concerning the illustrations, both J. Héring and J. P. M. Sweet note that in the light of the assertions we would expect them to be the reverse of what they are. While tongues are asserted to be meant as a sign for unbelievers and prophecy for believers, the illustrations depict the negative effect of tongues upon unbelievers and the positive effect of prophecy not on believers but upon unbelievers. The second assertion (υ. 22b) in particular contradicts the second illustration (υυ. 24–5) in that it clearly states that ‘prophecy is meant as a signnot for unbelieversbut for believers’. This is so if σημεĩον is taken in a positive sense. If, on the other hand, it is taken in a negative sense, the logical relation of this second illustration to the second assertion becomes ambiguous.

High Performance Concrete with Ternary Binders

2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Condensed Silica Fume

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.

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