Effects of end conditions on compressive strength and static elastic modulus of very high strength concrete

2002 ◽  
Vol 32 (10) ◽  
pp. 1545-1550 ◽  
Author(s):  
Mehmet Gesoǧlu ◽  
Erhan Güneyisi ◽  
Turan Özturan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
End Conditions ◽  
Very High

Performance Deterioration of High Strength Concrete under Mixed Erosion and Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 1655-1660
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Xiao Ning Zheng ◽  
Yan Dong Li
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
High Strength ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Dynamic Modulus Of Elasticity

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.

scholarly journals Multigene Genetic Programming for Estimation of Elastic Modulus of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alireza Mohammadi Bayazidi ◽  
Gai-Ge Wang ◽  
Hamed Bolandi ◽  
Amir H. Alavi ◽  
Amir H. Gandomi
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Genetic Programming ◽  
High Strength Concrete ◽  
Elastic Moduli ◽  
High Strength ◽  
Test Results ◽  
Strength Concrete ◽  
Multigene Genetic Programming ◽  
Compressive Strength Test

This paper presents a new multigene genetic programming (MGGP) approach for estimation of elastic modulus of concrete. The MGGP technique models the elastic modulus behavior by integrating the capabilities of standard genetic programming and classical regression. The main aim is to derive precise relationships between the tangent elastic moduli of normal and high strength concrete and the corresponding compressive strength values. Another important contribution of this study is to develop a generalized prediction model for the elastic moduli of both normal and high strength concrete. Numerous concrete compressive strength test results are obtained from the literature to develop the models. A comprehensive comparative study is conducted to verify the performance of the models. The proposed models perform superior to the existing traditional models, as well as those derived using other powerful soft computing tools.

L'utilisation des bétons à très haute résistance au Canada

1989 ◽  
Vol 16 (5) ◽  
pp. 661-668
Author(s):  
Pierre Laplante ◽  
Pierre-Claude Aïtcin
Keyword(s):  
Compressive Strength ◽  
North America ◽  
High Strength Concrete ◽  
High Strength ◽  
Cement Ratio ◽  
Strength Concrete ◽  
Chicago Area ◽  
New Type ◽  
Ready Mixed Concrete ◽  
Very High

In the late sixties, several concrete producers in the Chicago area developed very high strength concrete. The compressive strength of this new type of concrete was increased gradually, and it is now possible to buy 100 MPa ready-mixed concrete in several places in North America. Of significant technological importance, very high strength concrete is becoming popular all over North America due to its profitability. As to why and how very high strength concrete is made, the readily available answers to the first question contrast with the predominately empirical approach that has characterized research into producing very high strength concrete up to now. In fact, there are no miracle mixes that will universally guarantee the availability of 100 MPa ready-to-use concretes. Nonetheless, some guidelines have been established that should be followed in order to avoid various pitfalls. In Canada, very high strength concrete is beginning to be used in the Toronto and Montreal areas. This paper summarizes the principal results obtained on two specific projects: the construction of an experimental column in Montreal in 1984, and the construction of Nova Scotia Plaza in Toronto in 1986. Key words: high-strength concrete, water/cement ratio, superplasticizer, silica fume, slag.

The Influence of Super-Fine Steel Slag on the Properties of High-Strength Concrete

2013 ◽  
Vol 477-478 ◽  
pp. 941-944 ◽  
Author(s):  
Jing Jing Feng ◽  
Xiao Qing Wang ◽  
Shan Shan Wang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
High Strength Concrete ◽  
Steel Slag ◽  
High Strength ◽  
Cement Concrete ◽  
Strength Concrete ◽  
Good Ability

The properties of the concrete with super-fine steel slag were compared with those of the pure cement concrete. Results show that the concrete with 20% super-fine steel slag has similar compressive strength, elastic modulus, and permeability with the pure cement concrete at the age of 28 and 90 days. The addition of super-fine steel slag tends to decrease the initial slump of concrete, but it has a good ability of prevention of slump loss. The concrete with super-fine steel slag has similar anti-carbonation capacity with the pure cement concrete. The concrete with 30% super-fine steel slag has lower compressive strength, lower elastic modulus, and higher permeability than the pure cement concrete.

Performance Comparison between High Strength Concrete and Ordinary Concrete under Mixed Erosion and Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 1667-1672
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Yan Dong Li ◽  
Xiao Ning Zheng
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
High Strength Concrete ◽  
Mass Loss Rate ◽  
Peak Stress ◽  
High Strength ◽  
Performance Comparison ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Ordinary Concrete

: Performance of high strength concrete and ordinary concrete under alternating action of mixed erosion and freeze-thaw cycling were compared. The erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. Results showed that, after 200 freeze-thaw cycles, the effect of surface scaling of ordinary concrete was more significant than that of high strength concrete, and the mass loss rate of ordinary concrete was much higher; The relative dynamic modulus of elasticity of high strength concrete slightly increased by 2.99%, while that of ordinary concrete decreased more than 13%. Compressive strength and elastic modulus of high strength and ordinary concrete behaved almost in the same way in the first 50 freeze-thaw cycles, with the increase of freeze-thaw cycles in the following test, the compressive strength and elastic modulus of ordinary concrete showed larger reductions than these of high strength concrete. As the freeze-thaw cycles increased, the corresponding strain to the peak stress of high strength concrete decreased, but it increased for ordinary concrete.

scholarly journals Comparison of the weathering behavior of a very high strength concrete with that of a standard concrete

Cerâmica ◽  
2008 ◽  
Vol 54 (332) ◽  
pp. 388-394
Author(s):  
A. Blandine ◽  
B. Essaïd ◽  
G. Bernard
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Inert Atmosphere ◽  
Spherical Particles ◽  
Interfacial Zone ◽  
Superficial Zone ◽  
Strength Concrete ◽  
Quartz Aggregates ◽  
Very High

We studied the weathering process of a very high strength concrete (VHSC) and compared it with that of a usual concrete. VHSC has compressive strengths much above 100 MPa after seven days of curing. The compressive strength is increased by lowering the value of the water/cement ratio and by improving the particle size distribution of the numerous residual anhydrous grains of clinker and of the quartz aggregates. A proportion of 15% of the cement is replaced by non-condensed silica fume, which consists of spherical particles of amorphous silica, 0.1 µm in diameter. This has the advantage to fill the space between clinker particles. Another advantage is to densify the interfacial zone between cement paste and aggregates. Afters 28 days of curing, the VHSC samples consist of quartz aggregates and residual anhydrous clinker particles linked to each other with a paste mainly composed of calcium silicate hydrate (C-S-H). Samples of VHSC were immersed in continuously renewed distilled water under inert atmosphere. After two months of exposure, chemical, mineralogical and textural changes have occurred in a superficial zone. The depth of the degraded zone is 300 µm. This value is much lower than the depth of the degraded zone formed in an usual mortar (800 µm) or in a common paste (1500 µm) leached in the same condition. At the surface of the weathered samples of VHSC, the anhydrous clinker particles have dissolved and the resulting holes of 10 µm diameter remained empty. At the frontier between the safe core and the weathered superficial zone, the holes resulting from the dissolution of clinker particles were filled with secondary C-S-H. As a conclusion, the low porosity of VHSC is a benefit for the compressive strength but also for the durability. The presence of numerous anhydrous clinker particles is not a problem.

Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Strength Concrete ◽  
Calcium Nitrite ◽  
Orientation Index ◽  
Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

Effect of Chopped Basalt Fiber on the Fresh and Hardened Properties of Fly Ash High Strength Concrete

2014 ◽  
Vol 567 ◽  
pp. 381-386 ◽  
Author(s):  
Nasir Shafiq ◽  
Muhd Fadhil Nuruddin ◽  
Ali Elheber Ahmed Elshekh ◽  
Ahmed Fathi Mohamed Salih
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Basalt Fiber ◽  
High Strength ◽  
Progressive Increase ◽  
Test Results ◽  
Strength Concrete ◽  
Hardened Properties ◽  
Chopped Basalt Fiber

In order to improve the mechanical properties of high strength concrete, HSC, several studies have been conducted using fly ash, FA. Researchers have made it possible to achieve 100-150MPa high strength concrete. Despite the popularity of this FAHSC, there is a major shortcoming in that it becomes more brittle, resulting in less than 0.1% tensile strain. The main objective of this work was to evaluate the fresh and hardened properties of FAHSC utilizing chopped basalt fiber stands, CBFS, as an internal strengthening addition material. This was achieved through a series of experimental works using a 20% replacement of cement by FA together with various contents of CBFS. Test results of concrete mixes in the fresh state showed no segregation, homogeneousness during the mixing period and workability ranging from 60 to 110 mm. Early and long terms of compressive strength did not show any improvement by using CBFS; in fact, it decreased. This was partially substituted by the effect of FA. Whereas, the split and flexural strengths of FASHC were significantly improved with increasing the content of CBFS as well as the percentage of the split and flexural tensile strength to the compressive strength. Also, test results showed a progressive increase in the areas under the stress-strain curves of the FAHSC strains after the CBFS addition. Therefore, the brittleness and toughness of the FAHSC were enhanced and the pattern of failure moved from brittle failure to ductile collapse using CBFS. It can be considered that the CBFS is a suitable strengthening material to produce ductile FAHSC.

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