1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.


2013 ◽  
Vol 639-640 ◽  
pp. 364-367 ◽  
Author(s):  
Xiao Bo Chen ◽  
Jian Yin ◽  
Wei Min Song

Based on engineering practice, autogenous volume deformation and creep properties of C60 high performance concrete(C60 HPC) and C60 high strength concrete(C60 HSC) were evaluated in the study. The results showed that the cement partly-replaced with fly ash could significantly decrease the creep deformation, creep coefficient and creep degree. In comparison with C60 HSC, the creep coefficient and creep degree of C60 HPC were decreased 17.9%and15.8% in 28 days, 22.9% and 21.0% in 270 days. For C60 HPC and C60 HSC at the same age, autogenous volume deformation of C60 HPC is greater than that of C60 HSC, but they were both less than 80×10-6 , and the autogenous volume deformation was basically completed in 7 days.


Author(s):  
Ramanpreet Singh ◽  
Gurprit Singh Bath ◽  
Manjeet Bansal

The framework of bridges, buildings, roads etc. need concrete. The concrete which is being used is not able to fulfil the contemporaneous needs. In India High Strength Concrete (HSC) is preferred for manufacturing practices and at the same time High Performance Concrete is used at high level. The properties of HSC are improved like mechanical and durability are improved by using silica fume in concrete. HSC has made the work of construction company more rewarding to design tall, long and light structures. HSC is helpful in designing buildings with good number of floors, wide area bridges and slim structure. The products like fly-ash, copper slag, silica fume etc. are produced by industries which leads to various environmental problems. The experiment on silica was done which stated that no strength is lost in silica-fume concretes. The experiment comprises four levels of silica-fume at the rate of 0%, 5.5%, 8.0%,9.5% and 11.0% which results high strength concrete.


2021 ◽  
Vol 16 (3) ◽  
pp. 237-250
Author(s):  
Svetlana Pushkar ◽  
Yuri Ribakov

ABSTRACT This study evaluated Life-Cycle Assessment (LCA) of two different designs of high-performance concrete beam: (1) a single-layer beam (SLB) that consisted of steel fibered high-strength concrete in both the compression and tensile zones and (2) a two-layer beam (TLB) that consisted of steel fibered high-strength concrete and normal-strength concrete in the compression and tensile zones, respectively. The SLB and steel fibered high-strength concrete layer of the TLB were of the same concrete class C70/85. LCAs of the SLB and TLB were conducted using the ReCiPe2016 midpoint and endpoint-single-score methods. The difference between the two endpoint-single-score results was evaluated using a two-stage nested analysis of variance. The ReCiPe2016 midpoint results showed that replacing the SLB with the TLB reduces the environmental impact of global warming potential, terrestrial ecotoxicity, water consumption, and scarcity of fossil resources by 15%, 17%, 11%, and 17%, respectively. The ReCiPe2016 endpoint-single-score results showed that the environmental damage from the TLB compared to the SLB was statistically reduced (p = 0.0256). Therefore, considering two different designs of steel fibered high-strength concrete beams, the TLB design was found environmentally preferable to SLB design on both, midpoint and endpoint-single-score evaluations.


2014 ◽  
Vol 919-921 ◽  
pp. 1830-1835
Author(s):  
Li Bin Xu ◽  
Nai Qian Feng ◽  
Ideris Zakaria ◽  
Bin Xing Wu

The high strength and high performance concrete C80~C100 is popularly used nowadays, especially in the West-Tower Project of Gungzhou. In order to provide reference for the use of high strength concrete and the development of ultrahigh pumping technology, the following six aspects were studied, namely the preparation of high strength concrete, the variation of the concrete mixture under high pressure, the index of the ultrahigh pumping concrete, the change after the pumping, the loss of the pumping pressure and the measurement of the pumping viscous resistance.


2018 ◽  
Vol 199 ◽  
pp. 11006
Author(s):  
M. Iqbal Khan ◽  
Wasim Abbass

The hybridization of fibers for arresting the crack in concrete is a key factor and play an important role to improve mechanical properties of high performance concrete with respect to mono fibers. The effect of hybridization of hooked end steel fibers with different length and diameter on mechanical properties of high strength concrete was investigated in this research work. The different percentages of hook ended fibers (60 mm and 40 mm) are hybridized in the concrete mixture while keeping total percentage of fibers by volume equal to 1%. The compressive and flexural properties with complete load verses deflection curves of hybrid steel fiber reinforced high performance concrete were investigated to find the optimized dosage of hybrid steel fibers. The results showed that the hybridization of fiber provided better compressive and flexural performance. It was also observed from the results that combination of 65% of 60 mm and 35% of 40 mm hooked end fibers proved to be best for enhancement in compressive and flexural properties.


2014 ◽  
Vol 629-630 ◽  
pp. 49-54
Author(s):  
Vlastimil Bílek ◽  
Vladimíra Tomalová ◽  
Petr Hájek ◽  
Ctislav Fiala

High strength concrete for the production of concrete railway sleepers was designed more than 20 years ago. The compressive strength of the concrete was very high from the start, but flexure strengths showed some irregular development - a decrease in time. Later, also a significant decrease of fracture properties was recorded. Microcracking was found to be the reason for this; therefore some modifications were performed to avoid this happening (especially the reduction of the maximum size of aggregates from 22 mm to 16 mm or 11 mm). Some problems concerning frost resistance of the concrete with a slag addition were reduced by applying ternary binders. All of the results are discussed from the point of view of a long-term observation of the strengths and fracture properties ́ development during the time period of 5 years or even more.


Author(s):  
A. Yu. Kovaleva ◽  
◽  
M. V. Stupak ◽  
A. S. Sidorova ◽  
◽  
...  

There have been analyzed some reference documents that contain requirements for high-performance concrete. The article presents the study results on the durability of high-strength concrete in weather resistance tests. It has been established that evaluation of durability of high-strength composites by strength and frost resistance without taking into account external factors is insufficient, which is confirmed in analysis of samples` structure.


2013 ◽  
Vol 838-841 ◽  
pp. 3-6 ◽  
Author(s):  
Jin Cai Zhu ◽  
Chang Wang Yan ◽  
Shu Guang Liu

Study of Constitutive relations of concrete based on Chinese and foreign scholars. This paper put forward constitutive equation that more close to the stress-strain data of high strength concrete under uniaxial compression, and make a comparison between the theoretical results and experimental data, and promising results were obtained. It can be used as a basis for researching of high strength and high performance concrete of other mechanical properties.


Author(s):  
C. Sukanya ◽  
Mr. R. Surya Prakash

This project is related on the use of Silica fume as a substitution of cement and 100% m- sand as fine aggregate. Concrete is the most widely utilized material in the construction industry and will hold good for years. The credit is attributed to the properties of concrete like excellent strength, durability and less maintenance costs. But in the recent years, the concrete industry is facing a big challenge mainly due to the cement which is a vital component. In order to improve the durability properties many types of special concretes such as High Strength Concrete, High Performance Concrete, Fibre Reinforced Concrete, Self-Compacting Concrete, etc. have been developed. High performance concrete has become an attractive option to Civil Engineers due to the special characteristics like early strength, ease of placement, permeability, mechanical and durability properties. The performance of High strength Concrete (HSC) is enhanced by the addition of admixtures which act as pozzolans as well as fillers, thereby improving the microstructure of the interfacial transition zone making it denser and impermeable. Silica Fume (SF) is a commonly used pozzolanic material owing to its high silicon dioxide content and fineness. This ultra fine property of SF used in concrete to improve its strength and durability.


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