High-Strength Concrete with Increased Fracture-Toughness

1990 ◽  
Vol 211 ◽  
Author(s):  
Mette Glavind ◽  
Tine Aarre
Keyword(s):  
Carrying Capacity ◽  
High Strength Concrete ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Strength Concrete ◽  
Linear Load ◽  
Load Carrying ◽  
Capacity Calculation ◽  
Normal Strength ◽  
Non Linear Load

AbstractThe application of high-strength concrete in practice is strongly limited by its more brittle behaviour than normal strength concrete.The present study deals with an investigation of the possibilities of increasing the fracture toughness of high-strength concrete by adding fibres. Tests are made with both normal strength concrete and high-strength concrete containing different amounts of steel and polypropylene fibres. Stress-strain curves in compression are obtained by a deformation controlled test system. The toughness is described with different toughness indexes.By using a previously proposed expression for the stress-strain curves, it is possible to make a non-linear load carrying capacity calculation for reinforced concrete beams. The results of the load carrying capacity calculation are compared with results of similar calculations made with the Danish code extrapolated to be valid for high-strength concrete.The investigation shows that the addition of especially steel fibres is effective in increasing toughness and the non-linear load carrying capacity for high-strength concrete. It is also shown that the compression strength of high-strength concrete is increased by addition of steel fibres. The results of the load carrying capacity calculation show that the Danish code cannot be extrapolated to be valid for high-strength concrete without any modifications.

scholarly journals Reduction of the Early Autogenous Shrinkage of High Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Drago Saje
Keyword(s):  
Carrying Capacity ◽  
High Strength Concrete ◽  
Autogenous Shrinkage ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Polypropylene Fibres ◽  
Strength Concrete ◽  
Load Carrying ◽  
Shrinkage Reducing Admixture

The results of a laboratory investigation on the early autogenous shrinkage of high strength concrete, and the possibilities of its reduction, are presented. Such concrete demonstrates significant autogenous shrinkage, which should, however, be limited in the early stages of its development in order to prevent the occurrence of cracks and/or drop in the load-carrying capacity of concrete structures. The following possibilities for reducing autogenous shrinkage were investigated: the use of low-heat cement, a shrinkage-reducing admixture, steel fibres, premoistened polypropylene fibres, and presoaked lightweight aggregate. In the case of the use of presoaked natural lightweight aggregate, with a fraction from 2 to 4 mm, the early autogenous shrinkage of one-day-old high strength concrete decreased by about 90%, with no change to the concrete's compressive strength in comparison with that of the reference concrete.

Experimental Study on Mechanical Properties of Axially Loaded PVC Tubed Short Concrete Columns

2011 ◽  
Vol 99-100 ◽  
pp. 715-718 ◽  
Author(s):  
Jun Dong ◽  
De Ping Chen ◽  
Ju Mei Zhao ◽  
De Shan Shan ◽  
Xin Yue Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Loading Condition ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Load Carrying Capacity ◽  
Composite Columns ◽  
Load Carrying ◽  
Strength And Deformation ◽  
Axially Loaded

Twelve PVC tubed short concrete columns and four columns without PVC tube confined were tested under axial load to investigate mechanical properties of axially loaded PVC tubed short concrete columns . The principal influencing factors such as concrete strength, loading condition and ratio of height to diameter were studied. Test results indicated that strength and deformation performance of core concrete increased as a result of the confinement of PVC tube. The PVC tube confinement effect on concrete will decrease with an increase in strength of concrete. Load- carrying capacity and deformation of short composite columns with different loading condition made some difference. As the ratio of height to diameter increases, load- carrying capacity and plasticity of short composite columns decreased gradually.

scholarly journals Rebars for Durable Concrete Construction: Points to Ponder

2021 ◽  
Author(s):  
Anil K. Kar
Keyword(s):  
Reinforced Concrete ◽  
Carbon Steel ◽  
Carrying Capacity ◽  
High Strength Steel ◽  
Global Climate ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Glass Fiber Reinforced ◽  
Load Carrying ◽  
Total Failure

Reinforced concrete is the number one medium of construction. It is important to have good quality concrete and reinforcing bar (rebar). It is equally important to have competent bond between rebar and concrete. About six decades ago ribbed rebars of high strength steel started replacing plain round bars of mild steel, the use of which had made reinforced concrete constructions durable. It was overlooked that ribbed rebars of carbon steel would be highly susceptible to corrosion at accelerated rates. That would not only make reinforced concrete constructions reach states of distress early, that could also destroy or reduce bond between ribbed rebars and concrete. The continued use of ribbed rebars of high strength carbon steel demonstrates a widespread lack of understanding of the phenomenon of bond between rebars and concrete. This lack of understanding of bond has led to the introduction of epoxy coated ribbed rebars, ribbed stainless steel bars and glass fiber reinforced and granite reinforced polymer rebars, all of which permit reinforced concrete carry static loads because of engagement between such rebars and concrete. But the load-carrying capacity of reinforced concrete elements is impaired, and such elements become vulnerable to local or even total failure during vibratory loads. The use of PSWC-BAR, characterized by its plain surface and wave-type configuration, permits the use of medium strength and high strength steel. In the absence of ribs, the rate of corrosion is greatly reduced. The use of PSWC-BARs, at no added effort or cost, in lieu of conventional ribbed bars, leads to enhancement of effective bond or engagement between such rebars and concrete, thereby leading to increased load-carrying capacity, several-fold higher life span, ductility and energy-absorbing capacity, and great reduction in life cycle cost and adverse impact of construction on the environment and the global climate. In keeping with a lack of understanding of bond between rebars and concrete, there is arbitrariness in the selection of the required level of percent elongation and ductility of rebars.

Assessment of high-strength concrete encased steel composite columns subject to axial compression

2020 ◽  
Vol 164 ◽  
pp. 105765 ◽  
Author(s):  
Binglin Lai ◽  
J.Y. Richard Liew ◽  
Akshay Venkateshwaran ◽  
Shan Li ◽  
Mingxiang Xiong
Keyword(s):  
Axial Compression ◽  
High Strength Concrete ◽  
High Strength ◽  
Composite Columns ◽  
Strength Concrete ◽  
Steel Composite
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