Identification of Unknown Sediment in Water-Reducer

2014 ◽  
Vol 852 ◽  
pp. 27-31
Author(s):  
Sun Yi Si ◽  
Bing Hui Chen ◽  
Wen Zhang ◽  
Jia Wei Qian ◽  
Guo Qing Ding
Keyword(s):  
Water Consumption ◽  
Urban Population ◽  
High Performance ◽  
Large Scale ◽  
Building Materials ◽  
High Performance Concrete ◽  
Urbanization Level ◽  
Chemical Admixtures ◽  
Concrete Materials

As urbanization level of our country improves constantly, urban population will increase dramatically. Then industrial and civil buildings and other facilities will be multiplied, which leads to use plenty of high-performance concrete materials. i.e. China's building materials, especially the use of concrete will be increased year by year[. And the chemical admixtures is an essential fifth component of concrete[2-. It has been nearly 50 years since the chemical admixtures were researched,expolited and used in large scale[.But the water reducer are used most widely, its characteristics is to reduce the water consumption of concrete, and minimize the porosity of concrete. Thereby which enhances its intensity and durability.

Development of Some Performance-Based Material Specifications for High-Performance Concrete Pavement

2003 ◽  
Vol 1834 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Prasada Rao Rangaraju
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Pavement ◽  
Performance Criteria ◽  
Test Results ◽  
Department Of Transportation ◽  
Performance Specifications ◽  
Concrete Materials ◽  
Practical Feasibility

In collaboration with FHWA, the Minnesota Department of Transportation (Mn/DOT) has successfully completed its first experimental high-performance concrete pavement (HPCP) project under the Testing and Evaluation Program (TE-30). This project is one of the 22 projects funded under the TE-30 Program. With a structural design life of 60 years, this HPCP is unique in that it incorporates significant changes to the existing Mn/DOT specifications on concrete materials. Some of the new materials-related specifications developed as a part of this project are based on performance criteria that influence long-term durability of the pavement structure. The background and considerations for selecting the new performance measures are discussed, and test results are presented that evaluate the practical feasibility of establishing and achieving the performance specifications.

scholarly journals Effect of Mineral Aggregates and Chemical Admixtures as Internal Curing Agents on the Mechanical Properties and Durability of High-Performance Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2090 ◽  
Author(s):  
Francisco Javier Vázquez-Rodríguez ◽  
Nora Elizondo-Villareal ◽  
Luz Hypatia Verástegui ◽  
Ana Maria Arato Tovar ◽  
Jesus Fernando López-Perales ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ions ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Pumice Stone ◽  
Chemical Admixtures ◽  
Mineral Aggregates

In the present work, the effect of mineral aggregates (pumice stone and expanded clay aggregates) and chemical admixtures (superplasticizers and shrinkage reducing additives) as an alternative internal curing technique was investigated, to improve the properties of high-performance concrete. In the fresh and hardened state, concretes with partial replacements of Portland cement (CPC30R and OPC40C) by pulverized fly ash in combination with the addition of mineral aggregates and chemical admixtures were studied. The physical, mechanical, and durability properties in terms of slump, density, porosity, compressive strength, and permeability to chloride ions were respectively determined. The microstructural analysis was carried out by scanning electronic microscopy. The results highlight the effect of the addition of expanded clay aggregate on the internal curing of the concrete, which allowed developing the maximum compressive strength at 28 days (61 MPa). Meanwhile, the replacement of fine aggregate by 20% of pumice stone allowed developing the maximum compressive strength (52 MPa) in an OPC-based concrete at 180 days. The effectiveness of internal curing to develop higher strength is attributed to control in the porosity and a high water release at a later age. Finally, the lowest permeability value at 90 days (945 C) was found by the substitutions of fine aggregate by 20% of pumice stone saturated with shrinkage reducing admixture into pores and OPC40C by 15% of pulverized fly ash. It might be due to impeded diffusion of chloride ions into cement paste in the vicinity of pulverized fly ash, where the pozzolanic reaction has occurred. The proposed internal curing technology can be considered a real alternative to achieve the expected performance of a high-performance concrete since a concrete with a compressive strength range from 45 to 67 MPa, density range from 2130 to 2310 kg/m3, and exceptional durability (< 2000 C) was effectively developed.

scholarly journals High Performance Concrete Materials with Applications in Building and Civil Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-3 ◽  
Author(s):  
Peng Zhang ◽  
Song Han ◽  
Serina Ng ◽  
Xu-Hao Wang
Keyword(s):  
High Performance ◽  
Civil Engineering ◽  
High Performance Concrete ◽  
Concrete Materials

Green High Performance Concrete Based on Sustainable Development

2014 ◽  
Vol 584-586 ◽  
pp. 1568-1572
Author(s):  
Ping Zhang ◽  
Ying Cao
Keyword(s):  
Sustainable Development ◽  
High Performance ◽  
High Performance Concrete ◽  
Construction Materials ◽  
Living Environment ◽  
The Sustainable Development ◽  
Green Concrete ◽  
Concrete Production ◽  
Concrete Materials ◽  
The Relationship

Green high performance concrete is concrete materials which can reduce the load of the earth's environment, coordinate development with the ecosystem and create comfortable living environment. The relationship between the construction materials and the sustainable development and the characteristic of green high performance concrete were introduced, the measures of green concrete production was analyzed and the work essential for the development of green high performance concrete was proposed in this paper. The research shows that the development of green high performance concrete is the inevitable way for the sustainable development of concrete.

scholarly journals Study on the Model of Creep and the Calculation of Stress Field for Concrete

2015 ◽  
Vol 9 (1) ◽  
pp. 990-996
Author(s):  
Guo Lei ◽  
Yang Zi Sheng
Keyword(s):  
Stress Field ◽  
Prediction Model ◽  
Test Data ◽  
High Performance ◽  
High Performance Concrete ◽  
Influencing Factor ◽  
Strain Increment ◽  
Creep Coefficient ◽  
Creep Stress ◽  
Concrete Materials

The exact prediction of creep is of great significance for the simulation of the stress field of concrete creep. To overcome the limitation of the current prediction model of creep, pertinent models abroad are referred and adopted so that other factors can be controlled under standard state but only the creep varies to evaluate the feasibility of the prediction model with current characteristic of concrete materials and available test data. In the prediction of creep of high performance concrete, any influencing factor can be quantified, therefore, a large number of test data are not required. It was also observed that the defects that factors pointed out were common in the prediction model of concrete. The calculation was simple and convenient and achieved a higher accuracy. In the calculation of creep stress field, the creep was calculated according to fitting creep degree. Based on this, this paper established the creep coefficient formulas for the calculation of strain increment, and deduced the number of finite element expressions which were used to calculate the creep stress field with creep coefficient.

scholarly journals The Use of Superabsorbent Polymers in High Performance Concrete to Mitigate Autogenous Shrinkage in a Large-Scale Demonstrator

2020 ◽  
Vol 12 (11) ◽  
pp. 4741
Author(s):  
Laurence De Meyst ◽  
Judy Kheir ◽  
José Roberto Tenório Filho ◽  
Kim Van Tittelboom ◽  
Nele De Belie
Keyword(s):  
High Performance ◽  
Large Scale ◽  
High Performance Concrete ◽  
Measurement Techniques ◽  
Mechanical Strain ◽  
Autogenous Shrinkage ◽  
Free Water ◽  
High Strength ◽  
Ring Test ◽  
Superabsorbent Polymers

High performance concrete (HPC) is a high strength concrete that undergoes a lot of early-age autogenous shrinkage (AS). If shrinkage is restrained, then micro-cracks arise and threaten the durability of the structure. Superabsorbent polymers (SAPs) can reduce/mitigate the autogenous shrinkage, due to their promising application as internal curing agents. In this paper, large-scale demonstrators were built to investigate the efficiency of SAPs to mitigate autogenous shrinkage in HPC. For this purpose, different measurement techniques were used like embedded fiber optic sensors and demountable mechanical strain gauges, complemented by AS measurements in corrugated tubes and restrained ring tests. The SAP wall showed an AS reduction of 22%, 54%, and 60% at the bottom, middle, and top, respectively, as recorded by the sensors (in comparison with the reference wall (REF)). In the corrugated tubes, mitigation of AS was shown in the SAP mixture, and under restrained conditions, in the ring test, the reference mixture cracked after two days, while the SAP mixture had not cracked at the end of the measurement period (20 days). Cracks were shown on REF wall after one day, while the SAP wall was crack-free. Water flow tests performed on the main crack of the REF wall confirmed that the flow rate is related to the third power of the crack width. All tests showed that SAPs could highly reduce AS in HPC and avoid cracking.

Permeability Measurement of High Performance Concrete at Elevated Temperature Employing a New Test Set-Up

2015 ◽  
Vol 1124 ◽  
pp. 288-293
Author(s):  
Michaela Fiedlerová ◽  
Johannes Kirnbauer ◽  
Heinrich Bruckner
Keyword(s):  
Elevated Temperature ◽  
High Performance ◽  
Building Materials ◽  
High Performance Concrete ◽  
Gas Permeability ◽  
Permeability Measurement ◽  
Test Set ◽  
Testing Procedures ◽  
Heating And Cooling ◽  
Set Up

This paper is focused on clarifying behaviour of concrete at elevated temperature with employing new test set-up constructed at Institute of Building Construction and Technology, Vienna University of Technology. This unique test set-up allows measuring gas permeability of different building materials such as concrete or ceramic at both high temperature (up to 400°C) and pressure (up to 6 bars). Present paper illustrates a new set up for permeability measurement during the heating and cooling and different testing procedures and evaluation of their influence on results.

Comparison of Different Types of Glass Reinforcement for HPC Facade Elements from Mechanical and Economical Aspects

2016 ◽  
Vol 722 ◽  
pp. 286-291 ◽  
Author(s):  
Lenka Laiblová ◽  
Tomáš Vlach ◽  
Michal Ženíšek ◽  
Anuj Kumar ◽  
Petr Hájek
Keyword(s):  
High Performance ◽  
Building Materials ◽  
High Performance Concrete ◽  
Environmental Parameters ◽  
Primary Energy ◽  
Textile Reinforced Concrete ◽  
Renewable Materials ◽  
Different Types ◽  
High Level ◽  
Glass Reinforcement

Concrete as the one of the most used material in civil engineering has also a very high negative environmental impact. In recent years’ environmental parameters of all building materials become the most important aspect. Especially reduction of concrete is becoming a very hot topic around the word because it can lead to the reduction of environmental impacts especially the consumption of primary energy, primary non-renewable materials and CO2 production. Textile reinforced concrete (TRC) is one of the possibilities to reduce amount of concrete in the structures. It is possible to design very thin structures because of non-corrosive properties of textile reinforcement and thus distinctly reduce the thickness. Combination with high performance concrete (HPC) allows to creating construction with mechanical properties on a required high level. This paper presents mechanical and economical comparison of different types of AR-glass reinforcement for HPC facade elements with the same amount of concrete.

scholarly journals Reducing the strength and durability loss of high performance ready mix and roller compacted concrete due to early age high temperature curing

2021 ◽  
Author(s):  
Richard Sluce
Keyword(s):  
High Temperature ◽  
High Performance ◽  
High Performance Concrete ◽  
Strength Loss ◽  
Early Age ◽  
Roller Compacted Concrete ◽  
Supplementary Cementing Materials ◽  
Chemical Admixtures ◽  
Strength And Durability ◽  
Ready Mix Concrete

This thesis reports the findings of a study conducted on the effects of mixing and curing high performance concrete at elevated temperature. The purpose of the study was to find solutions to ameliorate the strength and durability loss resulting from high temperature environments. This investigation is broken down into two distinct phases. Phase I consisted of a preliminary mortar investigation followed by Phase IIa which was conducted on ready mix concrete and Phase IIb which studied roller compacted concrete. Phase IIa investigated the ability of supplementary cementing materials and chemical admixtures to mitigate the deleterious effects of curing at high temperature. In contrast, Phase IIb investigated the ability of supplementary cementing materials to reduce the deleterious effects. It was found that supplementary cementing materials were moderately effective at ameliorating strength loss, and performed well in reducing durability loss. The chemical admixtures only performed well in ameliorating strength loss.

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