INVESTIGATION OF THE COMPRESSIVE STRENGTH OF PORTLAND CEMENT MIXTURES BY APPLICATION OF BACTERIA – ‘SPOROSARCINA PASTEURII’

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Samson Aregawi ◽  
Abiy Goshu ◽  
Bisrat Alemu ◽  
Dagmay Woldaregay ◽  
Nathnael Abdulkadir ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Yeast Extract ◽  
High Performance ◽  
High Performance Concrete ◽  
Test Results ◽  
Calcite Precipitation ◽  
Concrete Technology ◽  
Sporosarcina Pasteurii ◽  
The Past ◽  
Flow Table

The concept of microbial concrete is one of the recent advances in concrete technology. In the past two decades, concrete technologies are working towards developing high performance concrete. Researches over the globe are being carried out in the wake of promising results found on the improvement of cementitious mix performances due to the application of live microorganisms. In this research live microorganism named Sporosarcina pasteurii, soil bacterium, has been used. Different set of experiments were carried out to investigate the effect of the bacterial medium, bacterial nutrient and bacterial concentration. From the test results it was found out that the bacterial medium had little effect, while the bacterial nutrient, whose main constituent is yeast extract, significantly reduced the compressive strength and increased the flow table as well as the slump in both mortar and concrete. Those samples with aforementioned bacteria together with the bacterial nutrient showed an improved compressive strength. The micro behaviors observed in terms of compressive strength indicate that this gain of strength was due to the calcite precipitation induced by the bacteria. The paper concludes by stating the need of further investigation, especially with regards to finding a better substitute for yeast extract of the bacterial nutrient.

The ability of high performance concrete to resist high temperature

2017 ◽  
Vol 8 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Hassan A.M. Mhamoud ◽  
Jia Yanmin
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mass Loss ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Sharp Decrease ◽  
Test Results ◽  
Content Type ◽  
Chinese Standard

Purpose This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to mass loss and residual compressive and flexural strength. Design/methodology/approach Two mixtures were developed to test. The first mixture, OPC, was used as the control, and the second mixture was HPC. After 28 days under water (per Chinese standard), the samples were tested for compressive strength and residual strength. Findings The test results showed that at elevated temperatures of up to 500ºC, each mixture experienced mass loss. Below this temperature, the strength and the mass loss did not differ greatly. Originality/value When adding a 10 per cent silica fume, 25 per cent fly, 25 per cent slag to HPC, the compressive strength increased by 17 per cent and enhanced the residual compressive strength. A sharp decrease was observed in the residual flexural strength of HPC when compared to OPC after exposure to temperatures of 700ºC.

Study on the Compressive Strength and Mixing of Ultra-High Performance Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Properties ◽  
Test Method ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Ultra High Performance Concrete ◽  
Mixture Ratio

The test in order to obtain liquidity, higher intensity ultra-high performance concrete(UHPC), in the course of preparation, high intensity quartz sand to replace the ordinary sand,reasonable mixture ratio control low water-cement ratio,the incorporation of part of the test piece ofsteel fibers, produced eight specimens . In the ordinary molding and the standard conservation 28d thecase, the ultra-high-performance concrete compressive strength of more than 170MPa.Thepreparation of the test method and test results will provide the basis for further study of the law of themechanical properties of ultra high strength properties of concrete.

Confined capping system for compressive strength testing of high performance concrete cylinders

1995 ◽  
Vol 22 (3) ◽  
pp. 617-620 ◽  
Author(s):  
Claude D. Johnson ◽  
S. Ali Mirza
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Concrete Specimen ◽  
Strength Testing ◽  
Test Results ◽  
Testing Procedures ◽  
Testing Method ◽  
Concrete Cylinders

This paper presents a simple, inexpensive confined cap testing method which can be employed in the compressive strength testing of high performance concrete cylinders. An inexpensive customized cylinder capping apparatus and standard concrete laboratory testing equipment are employed. The paper describes the capping apparatus, capping and testing procedures, as well as test results for concrete compressive strengths up to and exceeding 100 MPa. Key words: capping, capping confinement, compressive strength, cylinders, end condition, grinding, high-strength concrete, specimen size, testing.

Application and Study of C80 High Performance Concrete in Freezing Shaft Sinking Techniques

2013 ◽  
Vol 353-356 ◽  
pp. 1577-1582
Author(s):  
Qian Wang ◽  
Tong Wei Lu ◽  
Lei Guo
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Test Results ◽  
Mine Shaft ◽  
Deep Freezing ◽  
Thawing Cycle ◽  
Shaft Sinking

A study on C80 high performance concrete used in deep freezing mine shaft liner is made. Test results are listed as follows: (1) Concretes compressive strength at 1 day is 53.0 MPa, while the compressive strength at 28 days is 93.5 MPa. (2) The diffusion coefficient of chloride ion at 28 days is 9.8×10-14m2/s, and freezing-thawing cycle is over 1000 times. The evidence above proves that this concrete can satisfy the requirements of C80 high performance concrete used in freezing shaft sinking techniques.

Influence of Metakaolin on Mechanical Properties of High-Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1904-1909
Author(s):  
Bao Min Wang ◽  
Wei Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Equal Mass ◽  
Test Results ◽  
Optimum Temperature ◽  
Compressive Strength Of Concrete ◽  
And Performance

Kaolin is a material with broad sources and a low price. Metakaolin is made from kaolin which is calcined, finely ground at an optimum temperature of 750 being kept constant for 4 hours. High strength and performance concrete can be mixed from metakaolin as a substitute for equal mass cement. The influences of 5%, 10% and 15% metakaolin in substitution of equal cement masses were studied on the mechanical properties of high-performance concrete. The test results showed that the addition of metakaolin improved the cubic compressive strength, splitting tensile strength and flexural strength of HPC, among which the improvement in compressive strength was the most siginificant, and simultaneously, there was also an improvement in concrete toughness in a certain degree. The optimum content of metakaolin is 10% resulting in an increase of the cubic compressive strength of concrete by 8.3% correspondingly.

scholarly journals The Influence of Ambient Temperature on High Performance Concrete Properties

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4646
Author(s):  
Alina Kaleta-Jurowska ◽  
Krystian Jurowski
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Water Penetration ◽  
Ambient Temperatures ◽  
Freeze Thaw ◽  
Air Content ◽  
Flow Table

This paper presents the results of tests on high performance concrete (HPC) prepared and cured at various ambient temperatures, ranging from 12 °C to 30 °C (the compressive strength and concrete mix density were also tested at 40 °C). Special attention was paid to maintaining the assumed temperature of the mixture components during its preparation and maintaining the assumed curing temperature. The properties of a fresh concrete mixture (consistency, air content, density) and properties of hardened concrete (density, water absorption, depth of water penetration under pressure, compressive strength, and freeze–thaw durability of hardened concrete) were studied. It has been shown that increased temperature (30 °C) has a significant effect on loss of workability. The studies used the concrete slump test, the flow table test, and the Vebe test. A decrease in the slump and flow diameter and an increase in the Vebe time were observed. It has been shown that an increase in concrete curing temperature causes an increase in early compressive strength. After 3 days of curing, compared with concrete curing at 20 °C, an 18% increase in compressive strength was observed at 40 °C, while concrete curing at 12 °C had a compressive strength which was 11% lower. An increase in temperature lowers the compressive strength after a period longer than 28 days. After two years of curing, concrete curing at 12 °C achieved a compressive strength 13% higher than that of concrete curing at 40 °C. Freeze–thaw performance tests of HPC in the presence of NaCl demonstrated that this concrete showed high freeze–thaw resistance and de-icing materials (surface scaling of this concrete is minimal) regardless of the temperature of the curing process, from 12 °C to 30 °C.

scholarly journals Experimental Contribution Concerning the Effect of Carbonation Reaction on the Oxygen Permeability of Concrete

2020 ◽  
Author(s):  
Mohamed El Ghazali Belgacem ◽  
Aissa Talah ◽  
Rui Neves ◽  
Farid Belhamel ◽  
Smail Kechidi
Keyword(s):  
Compressive Strength ◽  
Service Life ◽  
High Performance ◽  
Oxygen Permeability ◽  
High Performance Concrete ◽  
Test Results ◽  
Paper Test ◽  
Carbonation Reaction ◽  
Rc Structures ◽  
Concrete Mixtures

Reinforced concrete (RC) structures are prone to steel corrosion that affects their service life. The two main processes, involved in the destruction of the steel-concrete self-protection are the carbonation and the penetration of chlorides. Understanding the behavior of these degrading phenomena is of paramount importance to enhance the field of predicting the service life of RC structures. In this investigation, a total number of 54 cylindrical specimens (150×100 mm2) and 54 cubic specimens (100×100 mm2) from six different concrete mixtures covering a range of water-to-cement ratio (w/c) between 0.76 and 0.36 was tested. The effect of the carbonation reaction on the concrete oxygen permeability (assessed by a recent method), compressive strength, and weight has been investigated. The obtained data were analyzed to establish correlations to predict the oxygen permeability of non-carbonated concrete with concrete characteristics such as w/c ratio and compressive strength. Test results show good correlations. The results of the accelerated carbonation test showed that compressive strength increases with carbonation. Concerning the effect of carbonation reaction on concrete oxygen permeability which is the main goal of this paper, test results showed that carbonation considerably affects the concrete permeability. This result was observed for all concrete mixtures. Moreover, the relationship between carbonation depth and concrete oxygen permeability in ordinary concrete differed than high performance concrete. Furthermore, the increase of the oxygen permeability observed after the carbonation has been justified by the analysis of the Scanning Electron Microscopy images that show the formation of larger pores in comparison with non-carbonated concrete.

scholarly journals The influence of superplasticizer and shrinkage reducing admixture type on air-content and related properties of HPSCC

2020 ◽  
Vol 322 ◽  
pp. 01040
Author(s):  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Compressive Strength ◽  
Water Permeability ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
High Porosity ◽  
Test Results ◽  
Air Content ◽  
Shrinkage Reducing Admixture ◽  
Aerated Concrete

Theoretically, high-performance concrete with w/c ratio about 0.30 and w/b about 0.28 should have low porosity, low water permeability and high strength. The purpose of this study was to examine the influence of the superplasticizers( with and without air-entraining effect) and shrinkage reducing admixture based on a high molecular weight basis alcohol amount on the air-content, compressive strength, shrink and resistance to water penetration of high-performance self-compacting concrete (HPSCC). The test results have shown that despite the low water content, concrete modified with inadequately selected SP and high amount of SRA has a high porosity and low strength and water permeability. The types of superplasticizers and amount of SRA are significant due to porosity parameters, compressive strength and water-permeability of HPSCC. The water permeability and compressive strength of HPSCC depending on the effects of amount of SRA admixtures on the volume of pores in HPSCC. Moreover, shrinkage of incidental air-entrained concrete, despite its lower endurance, after 28 days of hardening it is smaller than non-aerated concrete.

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