scholarly journals Research of Polyocarboxy Acid Water-Reducer with Modified Ployether and its Effect on Concrete’s Workability

2011 ◽  
Vol 250-253 ◽  
pp. 2032-2035 ◽  
Author(s):  
Lu Feng Pang ◽  
Xin Xin Zhou
Keyword(s):  
High Performance ◽  
High Performance Liquid Chroma ◽  
Reducing Agents ◽  
Acid Water ◽  
Concrete Mixture ◽  
Synthetic Temperature ◽  
Naphthalene Series ◽  
High Range

In this paper, polycarboxylic type high performance water reducers have been synthesized through using TPEG modified monomer. If synthetic temperature and addition time of copolymer monomers can be controlled, the performance of polycarboxylic superplasticizer will be improved. Testing results indicates that when temperature is at 60~65°C, addition time of copolymer monomers is three hours, the performance of superplasticizer is best. Through High Performance Liquid Chroma- tography (HPLC) testing, we can find it is almost the same with the famous brand abroad of the same type. The ues of polycarboxylic type high performance water reducers cooperated with naphthalene series high range water reducing agents thereby markedly improv the workability of concrete mixture.

scholarly journals The Effect of the Morphology of Coarse Aggregate on the Properties of Self-Compacting High-Performance Fibre-Reinforced Concrete

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1372 ◽  
Author(s):  
Krzysztof Ostrowski ◽  
Łukasz Sadowski ◽  
Damian Stefaniuk ◽  
Daniel Wałach ◽  
Tomasz Gawenda ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Physical And Mechanical Properties ◽  
Concrete Mixture ◽  
Rheological Parameters ◽  
Transverse Strain ◽  
Fibre Reinforced Concrete ◽  
High Performance Fibre

When understanding the effect of the morphology of coarse aggregate on the properties of a fresh concrete mixture, the strength and deformability of self-compacting high-performance fibre-reinforced concrete (SCHPFRC) can be seen to be critical for its performance. In this research, regular and irregular grains were separated from granite coarse aggregate. The morphology of these grains was described while using digital image analysis. As a result, the aspect ratio, roundness and area ratio were determined in order to better understand this phenomenon. Then, the principal rheological, physical, and mechanical properties of SCHPFRC were determined. The obtained results indicated that the morphology of the grains of coarse aggregate has an impact on the strength and stiffness properties of SCHPFRC. Moreover, significant differences in the transverse strain of concretes were observed. The morphology of the coarse aggregate also has an impact on the rheological parameters of a fresh concrete mixture. To better understand this phenomenon, the hypothesized mechanism of the formation of SCHPFRC caused by different morphology of coarse aggregate was proposed at the end of the article.

scholarly journals Synthesis and characterization of a high performance polycarboxylic acid water reducing agent

2020 ◽  
Vol 198 ◽  
pp. 01018
Author(s):  
Qiong Yan ◽  
Liangke Yao ◽  
Yongzhong Xia ◽  
Shishan Liu ◽  
Lingcong Chen
Keyword(s):  
High Performance ◽  
Chain Transfer ◽  
Reducing Agent ◽  
Acid Water ◽  
Synthesis Process ◽  
Process Conditions ◽  
Polycarboxylic Acid ◽  
Synthetic Process ◽  
Working Performance

The optimal synthesis process conditions of polycarboxylic acid water reducers were investigated and characterized by infrared spectroscopy as well as GPC using high performance polycarboxylic acid water reducers synthesized by isoproterenol polyoxyethylene ether polymerized with acrylic acid and introducing unsaturated monomeric dibasic ester. The results showed that the optimum synthetic process conditions were as follows: acid-ether ratio of 3.0:1, amount of binary ester as 2.8% of monomer mass, amount of initiator as 0.35% of monomer mass, amount of chain transfer agent as 0.35% of monomer mass; the initial slump and initial expansion of the concrete of the synthetic water-reducing agent PCE-H were greater than those of the commercially available polycarboxylic acid water-reducing agent PCE-W, and the working performance of the concrete was better. PCE-H also has no adverse effect on strength.

The Determination of Frost Resistance on Ultra High Performance Concrete

2014 ◽  
Vol 1025-1026 ◽  
pp. 1005-1009 ◽  
Author(s):  
Michaela Kostelecká ◽  
Jiří Kolísko
Keyword(s):  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Silica Sand ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Normal Concrete ◽  
Different Types ◽  
High Range

The ultra high performance concrete (UHPC) has very special properties that are expressively different of normal concrete. Due to its high compression strength greater than 150 MPa, tensile strength greater than 20 MPa and improved durability, these represent significant advances in concrete technology. These materials include Portland cement, silica fume, quartz flour, fine silica sand, high-range water-reducer, water and either steel or organic fibres. Depending on the type of fibres used can influence the compressive strength. The article describes the tests of frost resistance on UHPC plates with different types of textiles armatures. The aim of the testing is describe influence of textiles armatures in UHPC matrix in extreme conditions.

scholarly journals Effect of added the polycarboxylate ether on slump retention and compressive strength of the high-performance concrete

2018 ◽  
Vol 195 ◽  
pp. 01020 ◽  
Author(s):  
Jonbi Jonbi ◽  
Resti Nur Arini ◽  
Basori Anwar ◽  
Mohamad Ali Fulazzaky
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Civil Engineering ◽  
High Performance Concrete ◽  
Concrete Mixture ◽  
Concrete Sample ◽  
Strength Tests ◽  
Polycarboxylate Ether ◽  
Insight Into ◽  
Durability Of Concrete

It is well known that workability of high performance concrete (HPC) is dependent on slump value of concrete mixture. Moreover, slump retention is the most sensitive compared to a well-known slump value because it represents the durability of concrete mixture for its applications in the field of civil engineering. This research used the polycarboxylate ether (PCE) to increase slump value of concrete mixture and then verified the effect of PCE on the slump retention and compressive strength of different high-performance concretes. 0%, 0.5%, 1%, 2% of PCE were added into concrete mixture to yield a minimum compressive strength of f’c 50 MPa. The slump retention tests were performed at 0, 15, 30, 45, 60 and 75 minutes while the compressive strength tests were carried out at 3, 7, 14 and 28 days for every concrete sample. The result findings showed that the optimal concrete performance can be achieved by adding 2% of PCE to reach at a slump retention value of 45 minutes and a compressive strength of 53.84 MPa. Effect of PCE on the slump retention and compressive strength has been verified to contribute an insight into the application of a proper designed workability of HPC.

Modified nanocarbon surfaces for high performance supercapacitor and electrocatalysis applications

2015 ◽  
Vol 51 (71) ◽  
pp. 13650-13653 ◽  
Author(s):  
Mohammed Es-Souni ◽  
Dimitri Schopf
Keyword(s):  
Carbon Nanotubes ◽  
High Performance ◽  
Precursor Solution ◽  
Reducing Agents ◽  
Leidenfrost Temperature

A supported porous nanocarbon film is heated slightly above the Leidenfrost temperature and directly transferred to an aqueous precursor solution of carbon nanotubes (CNTs) and Pt to form an adherent layer of Pt-NP decorated CNTs without the need for reducing agents.

scholarly journals Properties and Microstructure Distribution of High-Performance Thermal Insulation Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2091 ◽  
Author(s):  
Malek Mohammad ◽  
Eyad Masad ◽  
Thomas Seers ◽  
Sami G. Al-Ghamdi
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
High Performance ◽  
Lightweight Concrete ◽  
Concrete Mixture ◽  
Unit Weight ◽  
Expanded Perlite ◽  
Micro Computed Tomography ◽  
Structural Applications

The aim of this experimental study is to develop high strength and lightweight concrete mixture suitable for structural applications. This work investigates the effect of replacing normal aggregate either partially or totally with expanded perlite aggregate. This material allows for better thermal insulation properties, thus decreasing the energy usage within the life cycle of the concrete structure. Expanded perlite aggregate was used in concrete by 20%, 40%, 60%, 80%, and 100% in replacement of the natural aggregate. Material characterization tests of compressive strength, flexural strength, and thermal conductivity were carried out for six concrete mixtures. In addition, microstructure analysis was performed with the aid of a micro-computed tomography system to investigate the effects and relation of microstructure quantities on material properties. The proposed concrete mixture, which has 100% of expanded perlite aggregate, has a unit weight of 1703 kg/m3 and achieved reduction percentage of thermal conductivity around 62% (1.81 to 0.69 W·m−1·K−1) and a compressive strength of 42 MPa at 28 days; and thus is ideal for structural applications with enhanced properties.

scholarly journals High-performance sono/nano-catalytic system: Fe3O4@Pd/CaCO3-DTT core/shell nanostructures, a suitable alternative for traditional reducing agents for antibodies

2020 ◽  
Vol 61 ◽  
pp. 104824 ◽  
Author(s):  
Reza Taheri-Ledari ◽  
Ali Maleki ◽  
Ehsan Zolfaghari ◽  
Maral Radmanesh ◽  
Hodjattallah Rabbani ◽  
...  
Keyword(s):  
Catalytic System ◽  
High Performance ◽  
Reducing Agents ◽  
Core Shell ◽  
Suitable Alternative ◽  
Shell Nanostructures

Developing High-Performance Concrete Mix for New York State Bridge Decks

1996 ◽  
Vol 1532 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Donald A. Streeter
Keyword(s):  
New York ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
New York State ◽  
Concrete Mixture ◽  
Primary Concern ◽  
Increased Strength ◽  
Testing Field ◽  
Class F Fly Ash

The development and implementation of a more durable concrete mixture for bridge decks are described. The work began with review and evaluation of published results of research conducted by others and resulted in a new concrete mixture that has been designated Class HP for high performance. It has better handling and workability characteristics, improved resistance to chloride intrusion, and greater resistance to cracking, and it displays little or no surface scaling. Increased strength was not a primary concern in producing a high-performance concrete for bridge decks, but greater ultimate strength was nevertheless achieved. Class HP concrete is a modification of New York State's standard Class H concrete, incorporating two pozzolan substitutions for cement—20 percent Class F fly ash and 6 percent microsilica. On the basis of satisfactory laboratory testing, field trial, and field production it is being recommended for use statewide. Initial increases in cost are expected to be minimized as concrete producers and contractors become familiar with its mixing and placement. The first-cost increase will be easily offset by more than doubling service life expectancy. Further investigation is progressing to optimize performance of Class HP concrete in bridge decks and for its use in other concrete applications.

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