scholarly journals INVESTIGATIONS ON THE RELATIONSHIP BETWEEN POROSITY AND STRENGTH OF ADMIXTURES MODIFIED HIGH PERFORMANCE SELF-COMPACTING CONCRETE

2016 ◽  
Vol 22 (4) ◽  
pp. 520-528 ◽  
Author(s):  
Beata ŁAŹNIEWSKA-PIEKARCZYK
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Total Porosity ◽  
Self Compacting Concrete ◽  
Research Results ◽  
Air Content ◽  
New Generation ◽  
The Relationship ◽  
Viscosity Modifying Admixture

The influence of a type of new generation: superplasticizer (SP), anti-foaming admixture (AFA) and viscosity modifying admixture (VMA) on the air-content, workability of high performance self-compacting concrete (HPSCC) is analyzed in the paper. The purpose of this study was to examine the influence of type of the admixtures on porosity of HPSCC in the aspect of the compressive strength. The research results indicated that type of admixtures and its combina­tions result in different strengths of HPSCC, regardless of the total porosity characteristics of HPSCC.

THE INFLUENCE OF THE TYPE OF ANTI-FOAMING ADMIXTURE AND SUPERPLASTICIZER ON THE PROPERTIES OF SELF-COMPACTING MORTAR AND CONCRETE

2012 ◽  
Vol 18 (3) ◽  
pp. 408-415 ◽  
Author(s):  
Beata Łazniewska-Piekarczyk ◽  
Janusz Szwabowski
Keyword(s):  
Compressive Strength ◽  
Air Entrainment ◽  
Similar Degree ◽  
Air Bubbles ◽  
Self Compacting Concrete ◽  
Research Results ◽  
Porosity Structure ◽  
Air Content ◽  
Loss Of Self ◽  
Sem Analyses

To prevent excessive air entrainment, superplasticizers (SPs) should not only be compatible with cement, but also should not create the air-entraining effect in mortar. In order to counteract excessive air entrainment, anti-foaming admixtures (AFAs) can be used to prevent the formation of air bubbles. This paper investigates the influence of the type, amount and time of introduction of AFAs on air-entrainment, rheological properties and workability loss of self-compacting mortar. The research results prove that AFAs decrease air-content in mortar. Mortar containing an AFA does not undergo segregation, as is the case with mortars of a similar degree of fluidity with no AFA and incorporating an SP only. Moreover, mortar with an AFA keeps initial consistency for longer in comparison to mortar with a SP only. The properties of hardened mortar mixes are also investigated. The research results show that AFAs do not have a significant influence on the compressive strength of mortar mixtures. The compressive strength of mortar mixtures incorporating an AFA is similar to mortar with a non-air-entraining SP. Moreover, AFAs increase significantly the flexural strength of mortar. In most cases, AFAs do not decrease the absorbability of mortar. Only two types of AFAs increase slightly the absorbability of mortar. In order to explain this phenomenon, a research was performed investigating the porosity structure according to the EN 480-11 (1999) and SEM analyses of two types of self-compacting concrete (SCC): one made of mortar with an AFA and the other without AFA. The freeze-proof resistance of SCC (made of the same mortar mixes) was also investigated according to PN-88/B-06250 (2003). The results show that the type of AFA and SP significantly influences porosity characteristics and frost-resistance of SCC.

The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste

1984 ◽  
Vol 42 ◽  
Author(s):  
Huang Yiun-Yuan ◽  
Ding Wei ◽  
Lu Ping
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cement Paste ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
New Information ◽  
The Relationship ◽  
Empirical Constants

AbstractThe pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.

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.

Design of Mix Proportion of Cement Mortar with High-Performance Composite Semi-Flexible Pavement

2013 ◽  
Vol 641-642 ◽  
pp. 342-345 ◽  
Author(s):  
Ya Jun Wang ◽  
Chang Ying Guo ◽  
Yan Feng Tian ◽  
Jian Jun Wang
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Cement Mortar ◽  
Rupture Strength ◽  
Flexible Pavement ◽  
Mixture Ratio ◽  
Cement Ratio ◽  
Mix Proportion ◽  
High Performance Composite ◽  
The Relationship

Nine groups of cement mortar with different mix proportion were designed to measure their fluidity 0h, 0.25h, 0.5h, 0.75h and 1h later, compressive strength and rupture strength of 3d, 7d and 28d were also tested to find out the relationship between compressive strength, rupture strength, water-cement ratio and sand-cement ratio by software Origin. Considered the three factors above, the optimum mixture ratio was determined finally to meet the requirements.

Investigation and Application of High Performance Concretes

2010 ◽  
Vol 659 ◽  
pp. 517-521
Author(s):  
Viktória Sugár ◽  
Márton Takács ◽  
Vilmos Ovári
Keyword(s):  
Bulk Density ◽  
High Performance ◽  
Research Work ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Concrete Technology ◽  
Normal Concrete ◽  
Air Content ◽  
The Mean

Recent research work of the authors is dealing with preparing, investigation and application of high performance concretes (HPC) produced by the mean of results of modern concrete technology. These special types of concrete have one or more outstanding properties conversely the normal concrete. This article is focusing on the results of the experiments regarding self compacting concrete (SCC). During the investigation, effects of the fine-graded fraction was studied, which is indispensable component of the SCC. The effects of bulk density, consistency, air content, compressive strenght were analysed on fresh and hardened concrete.

scholarly journals Prediction of the compressive strength of high-performance self-compacting concrete by an ultrasonic-rebound method based on a GA-BP neural network

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250795
Author(s):  
Guoqiang Du ◽  
Liangtao Bu ◽  
Qi Hou ◽  
Jing Zhou ◽  
Beixin Lu
Keyword(s):  
Neural Network ◽  
Compressive Strength ◽  
Correlation Coefficient ◽  
High Performance ◽  
Ultrasonic Pulse Velocity ◽  
Test Sample ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Self Compacting Concrete ◽  
Bpnn Model

To address the problem of low accuracy and poor robustness of in situ testing of the compressive strength of high-performance self-compacting concrete (SCC), a genetic algorithm (GA)-optimized backpropagation neural network (BPNN) model was established to predict the compressive strength of SCC. Experiments based on two concrete nondestructive testing methods, i.e., ultrasonic pulse velocity and Schmidt rebound hammer, were designed and test sample data were obtained. A neural network topology with two input nodes, 19 hidden nodes, and one output node was constructed, and the initial weights and thresholds of the resulting traditional BPNN model were optimized using GA. The results showed a correlation coefficient of 0.967 between the values predicted by the established BPNN model and the test values, with an RMSE of 3.703, compared to a correlation coefficient of 0.979 between the values predicted by the GA-optimized BPNN model and the test values, with an RMSE of 2.972. The excellent agreement between the predicted and test values demonstrates the model can accurately predict the compressive strength of SCC and hence reduce the cost and time for SCC compressive strength testing.

scholarly journals An Experimental Assessment of the Water Permeability of Concrete with a Superplasticizer and Admixtures

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5624
Author(s):  
Zdzisław Skutnik ◽  
Mariusz Sobolewski ◽  
Eugeniusz Koda
Keyword(s):  
Compressive Strength ◽  
Water Permeability ◽  
Engineering Practice ◽  
Bridge Construction ◽  
Experimental Assessment ◽  
Air Content ◽  
Short Period ◽  
New Generation ◽  
First Time ◽  
Flow Pump

This study presents a flow pump technique usually used for evaluating the permeability of soils, which was, for first time, applied to measure the water permeability of concrete. Additionally, a new easy-to-apply method to determine permeability is proposed, based on a modification of Valenta’s formula. In the calculations, the apparent air content of concrete mixes was taken into account. An additional purpose of the conducted research was to determine the influence of a new generation of polycarboxylate superplasticizer and chemically active admixtures on the permeability, compressive strength, and other properties of concrete. The following four types of concrete were tested: concrete without admixtures, concrete with an admixture to increase the compressive strength, concrete with a superplasticizer, and concrete containing two admixtures simultaneously. The results showed that the proposed method allows to obtain reliable measurements within a very short period of time. The obtained results confirmed that new method may be very useful in engineering practice, particularly in terms of the watertightness of hydrotechnical concretes and the properties of the concretes used in bridge construction, underground parts of office buildings, or sealed tanks.

Compressive Strength and Hydration Process of Self Compacting Concrete (SCC) Mixed with Sea Water, Marine Sand and Portland Composite Cement

2014 ◽  
Vol 935 ◽  
pp. 242-246 ◽  
Author(s):  
M. Wihardi Tjaronge ◽  
Rita Irmawaty ◽  
Sakti Adji Adisasmita ◽  
Arwin Amiruddin ◽  
Hartini
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Sea Water ◽  
Water Shortage ◽  
Hydration Process ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Composite Cement ◽  
Static Modulus ◽  
Marine Sand

In order to eliminate the main problems of clean water shortage and fine aggregate in the low land areas and the distant islands, it is purpose to utilized the sea water, marine sand and Portland composite cement to produce the high performance Self-Compacting Concrete (SCC), where Portland composite cement containing of fly ash. The evaluation result on the mix design, workability (slump flow, segregation), mechanical properties (compressive strength-static modulus) and hydration process of SCC were discussed.

scholarly journals Compressive Strength of a Prescribed Control Mix for High Performance Self-compacting Concrete

2021 ◽  
Vol 1107 (1) ◽  
pp. 012009
Author(s):  
O G Mark ◽  
A N Ede ◽  
C Arum ◽  
G O Bamigboye ◽  
S O Oyebisi ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Self Compacting Concrete
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