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

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.

2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao

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.


2010 ◽  
Vol 168-170 ◽  
pp. 1904-1909
Author(s):  
Bao Min Wang ◽  
Wei Liu

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.


2020 ◽  
Vol 322 ◽  
pp. 01040
Author(s):  
Beata Łaźniewska-Piekarczyk

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.


2017 ◽  
Vol 8 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Hassan A.M. Mhamoud ◽  
Jia Yanmin

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.


2014 ◽  
Vol 875-877 ◽  
pp. 776-780
Author(s):  
Mojtaba Valinejad Shoubi ◽  
Azin Shakiba Barough ◽  
Iman Kiani

Concrete is the main material used in most of structures in the world. The use of high strength and high performance concrete to overcome deterioration due to static and dynamic load and some environmental burden in different situation such as chloride attack, sulphate attack and etc, is increasing worldwide. Achieving to a concrete with a high quality and saving in amount of material used for producing the concrete need a proper mix design method taken into account. DOE method is considered as an effective and substantial method in implementing the concrete mix design. In this paper, specifications and all mix design calculation steps using DOE method in achieving a high strength and high performance concrete for a tall building in a coastal environment based on three concrete cubes specimens produced in the lab, are investigated. The 7 and 14 day compressive strength test were implemented on the concrete cubes. At the end, it concluded that the specified compressive strength (45 N/mm2) can be achieved on the 28th day based on DOE method.


Author(s):  
Faiq M. Al-Zwainy ◽  
Hussam k. Risan ◽  
Rana I. K. Zaki

The purpose of this study was to conduct a meta-analysis that shows the influence of fiber on ultimate compressive strength and tensile strength of ultra-high performance concrete. The internet scholarly search engines and ScienceDirect article references were used to illustrate the papers concerning the experimental investigations of mechanical properties of ultra-high strength concrete with and without fiber with clearly, completely and comparative raw data. The normal concrete test results were dismissed from this search. Seven trials were identified based on the adopted inclusion and exclusion criteria above. The meta-analysis based on standardized mean difference was carried out on the basis of a fixed-effects model for the major outcomes of the ultimate compressive and tensile properties of ultra-high performance concrete. A total of 888 test specimens were enrolled in these seven trials. The combined analysis yielded a sign of a significant improvement in ultimate compressive strength and tensile strength of ultra-high strength concrete with fiber addition of 2% by concrete volume. The summary effect size of ultimate compressive strength was 2.34 while a more improvement in term of tensile strength with effect size of 2.64. By addition fiber of 2% provides a significant benefit in mechanical properties of ultra-high performance concrete.


2018 ◽  
Vol 7 (2.1) ◽  
pp. 79 ◽  
Author(s):  
V Srinivasa Reddy ◽  
R Nirmala

In the last three decades, supplementary cementitious materials such as fly ash, silica fume and ground granulated blast furnace slag have been judiciously utilized as cement replacement materials as these can significantly enhance the strength and durability characteristics of concrete in comparison with ordinary Portland cement (OPC) alone. Hence, high-performance concretes can be produced at lower water/powder ratios by incorporating these supplementary materials. One of the main objectives of the present research work was to investigate synergistic action of binary, ternary and quaternary blended high strength grade (M80) concretes on its compressive strength. For blended high strength grade (M80) concrete mixes the optimum combinations are: Binary blend (95%OPC +5% FA, 95%OPC +5% MS and 95%OPC +5%MK), ternary blend (65%OPC+20%FA+15%MS) and quaternary blend (50%OPC+28%FA+11%MS+11%MK). Use of metakaolin in fly ash based blended concretes enhances compressive strength significantly and  found to be cost effective in terms of less cement usage, increased usage of fly ash and also plays a major role in early strength development  of fly ash based blended concrete.  


2016 ◽  
Vol 677 ◽  
pp. 98-102 ◽  
Author(s):  
Michal Ženíšek ◽  
Tomáš Vlach ◽  
Lenka Laiblová

Durability and high strength of concrete are closely associated with low porosity and generally denser material structure. This is achieved using the addition, which include also silica fume. This article deal with an effective dosage of silica fume in high performance concrete, in a proportion of 0-25 % by the weight of cement. Compressive strength, rheological behaviour and economic benefits were the main questions in this work. The expected increase in compressive strength showed itself in lower doses of silica fume, while higher doses did not produce a further increase in strength. In the case of rheological behaviour, we can confirm lower bleeding and segregation, but also faster drying of the surface layer. From the economic point of view, a small doses of silica fume are better, because then we have observed the highest increase in strength.


2013 ◽  
Vol 353-356 ◽  
pp. 1577-1582
Author(s):  
Qian Wang ◽  
Tong Wei Lu ◽  
Lei Guo

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.


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