Effect of Superplasticizer on Self-Compactability of Fresh Concrete

1997 ◽  
Vol 1574 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Masahiro Ouchi ◽  
Makoto Hibino ◽  
Hajime Okamura
Keyword(s):  
Fresh Concrete ◽  
Experimental Results ◽  
Constant Independent ◽  
Self Compacting Concrete ◽  
Flow Area ◽  
Fixed Amount ◽  
The Difference ◽  
Lower Ratio ◽  
The Relationship

The effect of superplasticizer on the balance between flowability and viscosity of mortar in self-compacting concrete was investigated quantitatively. From experimental results, the ratio of funnel speed to flow area of mortar with a fixed amount of superplasticizer was found to be almost constant, independent of the water-powder ratio. A higher amount of superplasticizer resulted in a lower ratio of funnel speed to flow area. The ratio is proposed as an index for the effect of superplasticizer on mortar flowability and viscosity from the viewpoint of achieving self-compactability. This index is convenient for evaluating the amount of superplasticizer for proper flowability and viscosity of mortar using only one set of experimental results. The relationship between superplasticizer amount and its effect was found to differ depending on the type of powder or superplasticizer. The difference can be indicated quantitatively by the proposed index.

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 Prediction of Plastic Shrinkage Cracking of Self-Compacting Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Parviz Ghoddousi ◽  
Armin Monir Abbasi ◽  
Esmail Shahrokhinasab ◽  
Mohammad Abedin
Keyword(s):  
Shrinkage Strain ◽  
Climatic Conditions ◽  
Water Evaporation ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Shrinkage Cracking ◽  
Plastic Shrinkage ◽  
The Difference ◽  
The Relationship ◽  
Concrete Elements

Concrete exposed to hot climatic conditions is prone to plastic shrinkage after casting within the first few hours due to the water evaporation and restraining conditions of concrete. This cracking is more commonly observed in concrete elements with a large surface area exposed to drying. In this research, plastic shrinkage of 13 self-compacting concrete samples with different cement paste volumes and various coarse to total aggregate ratios was studied. Test specimens of fresh concrete were subjected to a wind tunnel, which simulated hot dry environmental condition immediately after casting. It can be observed from the test results that the relationship between free plastic shrinkage and the difference between bleeding and evaporation is direct and linear. Finally, a model for plastic shrinkage estimation was suggested by considering the effect of free plastic shrinkage strain, restraining factor, and tensile strain capacity of self-compacting concrete.

Generalized Two-Point Method Using Inverse Filtering for Surface Profile Measurement – Theoretical Analysis and Experimental Results for Error Propagation –

2014 ◽  
Vol 8 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Eiki Okuyama ◽  
◽  
Hiromi Ishikawa
Keyword(s):  
Theoretical Analysis ◽  
Error Propagation ◽  
Surface Profile ◽  
Sampling Interval ◽  
Experimental Results ◽  
Profile Measurement ◽  
Inverse Filtering ◽  
Multiple Sensors ◽  
The Difference ◽  
The Relationship

Error separation techniques of the surface profile from parasitic motions have been developed for the straightness profile measurement of a mechanical workpiece. These are known as software datums, which separate the surface profile from the parasitic motions by using multiple sensors and/or multiple orientations. The authors proposed a generalized twopoint method that used the difference with either integration or inverse filtering. This method can take any sampling interval. In this article, the relationship between the ratio of the sensor distance to the sampling interval and the error propagation at the lowest spatial frequency is clarified. Furthermore, experimental results are described to support the theoretical analysis of the error propagation.

scholarly journals Studies of Nutrients Speciation in the Solid Substrate Polystyrene Nutrients Anchored Material Using pH-Metric Method

2019 ◽  
pp. 413-422
Author(s):  
Kiriro G. Nduta ◽  
Isaac W. Mwangi ◽  
Ruth W. Wanjau ◽  
Jane I. Murungi ◽  
Paul K Mbugua ◽  
...  
Keyword(s):  
Transition State ◽  
Solid Substrate ◽  
Water Mixture ◽  
Fixed Amount ◽  
Relative Growth ◽  
Ph Variation ◽  
Aas Method ◽  
Nutrients Concentration ◽  
The Difference ◽  
The Relationship

Studies of relationship between pH variation and the nutrients distribution in the substrate/water mixture provides information about the concentration of the nutrients anchored in the substrate and the efficiency in which they are availed and controlled for plant relative growth. The technique for determining this relationship was based on measurement of changes in peak current (ip) by DPASV method, following different concentration of HNO3 added to a fixed amount of solid substrate polystyrene nutrients anchored material (M+). The total nutrients in the substrate residual (MLn-1) after several stripping experiments is determined by AAS method, the difference between the initial total nutrients concentration before stripping (MLn) and (M+ + MLn-1), gives the concentration of the nutrients in the transition state. The method is advantageous in that the relationship can be measured under conditions where nutrients in the solution controlled directly the current. The results were then modeled so as to make an estimation of the availability of plants nutrients anchored in the substrate. The results shows that at pH 5.5, 5.02×10-1µmol l-1of the nutrients had solubilized, 3.98×10-1µmol l-1was complexed and 15.23×10-1µmol l-1was in the transition state. This balance is enough to support plant growth without chemical burn.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

Klein with Lacan: A Study on the Reception of Lacanian Ideas in Uruguay and Its Effects on Clinical Practices (1955–82)

2020 ◽  
Vol 22 (3) ◽  
pp. 341-361
Author(s):  
Gonzalo Grau-Pérez ◽  
J. Guillermo Milán
Keyword(s):  
Clinical Practice ◽  
Clinical Material ◽  
Clinical Practices ◽  
Before And After ◽  
The Difference ◽  
The 1960S ◽  
The Relationship ◽  
Discursive Approach ◽  
The Way ◽  
Clinical Cases

In Uruguay, Lacanian ideas arrived in the 1960s, into a context of Kleinian hegemony. Adopting a discursive approach, this study researched the initial reception of these ideas and its effects on clinical practices. We gathered a corpus of discursive data from clinical cases and theoretical-doctrinal articles (from the 1960s, 1970s and 1980s). In order to examine the effects of Lacanian ideas, we analysed the difference in the way of interpreting the clinical material before and after Lacan's reception. The results of this research illuminate some epistemological problems of psychoanalysis, especially the relationship between theory and clinical practice.

The End of the Word as We Know It

2012 ◽  
Vol 6 (1-3) ◽  
pp. 165-184
Author(s):  
Timothy Beal
Keyword(s):  
Cultural Meanings ◽  
Cultural Icon ◽  
The Bible ◽  
Material Objectivity ◽  
The Difference ◽  
The Relationship

This essay attends to a distinction that requires closer examination and theorization in our discourse on iconic books and other scriptures: the difference between iconic object and cultural icon. How do we conceive of relations between the particular, ritualized iconicities of particular scriptures in particular religious contexts and the cultural iconicities of scriptures in general, such as “the Bible” or “the Quran,” whose visual and material objectivity is highly ambiguous? How if at all are the iconic cultural meanings of the ideas of such books related to the particular iconic textual objects more or less instantiate them? These questions are explored through particular focus on the relationship between the particular iconicities of particular print Bibles, as iconic objects, and the general iconicity of the cultural icon of the Bible.

Learning Language Levels in Students Accurate with a History Academic Achievement History

2017 ◽  
Vol 1 (2) ◽  
pp. 137
Author(s):  
Noorlela Binti Noordin ◽  
Abdul Razaq Ahmad ◽  
Anuar Ahmad
Keyword(s):  
Academic Achievement ◽  
Statistical Inference ◽  
Quantitative Data ◽  
Quantitative Methods ◽  
Descriptive Statistics ◽  
Language Test ◽  
The Subject ◽  
The Difference ◽  
Learning Language ◽  
The Relationship

This study was aimed to evaluate the Malay proficiency among students in Form Two especially non-Malay students and its relationship to academic achievement History. To achieve the purpose of the study there are two objectives, the first is to look at the difference between mean of Malay Language test influences min of academic achievement of History subject among non-Malay students in Form Two and the second is the relationship between the level of Malay proficiency and their academic achievement for History. This study used quantitative methods, which involved 100 people of Form Two non-Malay students in one of the schools in Klang, Selangor. This study used quantitative data were analyzed using descriptive statistics and statistical inference with IBM SPSS Statistics v22 software. This study found that there was a relationship between the proficiency of Malay language among non-Malay students with achievements in the subject of History. The implications of this study are discussed in this article.

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