Behavior of Densified Normal Strength Concrete under Elevated Temperature

2009 ◽  
Vol 405-406 ◽  
pp. 405-408 ◽  
Author(s):  
Bo Ming Zhao ◽  
Gai Fei Peng ◽  
Ting Yu Hao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fire Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Polymer Fiber ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength ◽  
Spalling Test

This paper presents an experimental investigation on fire resistance of densified normal strength concrete (DNSC), at water/binder (W/B) ratios of 0.45, 0.36, and 0.32, of which compressive strength of 28-days ranged from 42.5 MPa to 56.3 MPa. The results of the spalling test reveal that DNSC encountered explosive under high temperature. Polymer fiber can be used to improve fire resistance of DNSC. DNSC subjected to high temperature lost its mechanical properties in a similar manner to that of high-strength concrete.

Mechanical Properties and Durability of Bonded-Concrete Overlays and Ultrathin Whitetopping Concrete

2003 ◽  
Vol 1834 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Norbert Delatte ◽  
Anshuman Sehdev
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Normal Strength Concrete ◽  
Traffic Loading ◽  
Strength Concrete ◽  
Concrete Overlays ◽  
Normal Strength ◽  
Strength And Stiffness

Concrete overlays have been used for pavement and bridge-deck rehabilitation for many years. The mechanical properties and durability of several plain and fiber-reinforced concrete-overlay mixes were analyzed. Eight different concrete-overlay mix designs were investigated. The materials properties investigated were compressive and splitting tensile strength, modulus of elasticity, bond to concrete (with three different surface roughness characteristics), and durability. Freeze-thaw tests were performed to determine the durability of the concrete mixtures used. Strength and stiffness were investigated from 1, 3, 7, and 14 days. Laboratory tests on the strength and stiffness development of eight candidate concrete-overlay designs showed that high-strength concrete was appropriate for opening overlays to traffic in 24 h or less, but normal-strength concrete may be used if traffic loading may be delayed for 48 or 72 h. For larger projects, where paving continues over several days, normal-strength mixtures may be used when 48 to 72 h or more of curing can be achieved before traffic loading begins, with high-strength mixtures used for the last day's construction. All the high-strength concrete overlay-mixture designs tested appear to have satisfactory strength, stiffness, bond properties, and durability for use in bonded overlay construction. The normal-strength concrete is more economical than the high-strength concrete but develops its design properties more slowly.

Comparison Analysis on the Mechanical Properties of HSC and NSC after the Action of High Temperatures

2014 ◽  
Vol 1014 ◽  
pp. 49-52
Author(s):  
Xiao Ping Su
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Temperatures ◽  
High Strength Concrete ◽  
Elasticity Modulus ◽  
Strain Curve ◽  
Peak Stress ◽  
High Strength ◽  
Peak Strain ◽  
Strength Concrete

With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.

Innovative strategies for enhancing fire performance of high-strength concrete structures

2018 ◽  
Vol 21 (11) ◽  
pp. 1723-1732 ◽  
Author(s):  
Venkatesh KR Kodur
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Published Data ◽  
Structural Members ◽  
Fire Performance ◽  
Normal Strength Concrete ◽  
Innovative Strategies ◽  
Strength Concrete ◽  
Normal Strength ◽  
Fire Conditions

High-strength concrete is being increasingly used in a number of building applications, where structural fire safety is one of the primary design considerations. Many research studies clearly indicate that the fire performance of high-strength concrete is different from that of normal-strength concrete and that high-strength concrete may not exhibit same level of performance as normal-strength concrete under fire conditions. This article outlines key characteristics that influence the performance of high-strength concrete structural members under fire conditions. Data generated in previous experimental and numerical studies are utilized to illustrate various factors that influence fire performance of high-strength concrete structural members. Based on the published data, observations and trends on the behavior of high-strength concrete members, innovative strategies for mitigating spalling and enhancing fire resistance of high-strength concrete structural members are proposed.

Effect of amorphous metallic fiber on mechanical properties of high-strength concrete exposed to high-temperature

2019 ◽  
Vol 218 ◽  
pp. 448-456 ◽  
Author(s):  
Gyeongcheol Choe ◽  
Gyuyong Kim ◽  
Hongseop Kim ◽  
Euichul Hwang ◽  
Sangkyu Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Metallic Fiber

Influences of Glassified Micro-Bubble on Mechanical Properties of Ultra-High-Strength Concrete after Exposure to High Temperature

2014 ◽  
Vol 629-630 ◽  
pp. 259-264
Author(s):  
Gai Fei Peng ◽  
Xiao Li Wang ◽  
Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
High Temperature ◽  
High Strength Concrete ◽  
Room Temperature ◽  
High Strength ◽  
Strength Concrete ◽  
Micro Bubble ◽  
Residual Mechanical Properties ◽  
Tensile Splitting Strength

An experimental investigation was conducted to study residual mechanical properties of Ultra-High-Strength concrete with different dosages of glassified micro-bubble after exposure to high temperature. After exposure to different target temperatures (room temperature, 200 °C, 400 °C, 600 °C,800 °C), residual mechanical properties (residual compressive strength, residual tensile splitting strength, residual fracture energy) of Ultra-High-Strength concrete under different conditions including 1 water-binder ratios (0.18), 3 different contents of glassified micro-bubble (0%, 40%, 60%) were all investigated. The effect of different dosage of glassified micro-bubble was studied on residual mechanical properties of Ultra-High-Strength concrete after exposure to high temperature. The results indicate that the variations of different kinds of Ultra-High-Strength concrete with different dosage of glassified micro-bubble are basically the same. With the increase of temperature, the residual mechanical properties increase at first, then decrease. The residual mechanical properties decrease after exposure to high temperature of 800 °C.

Performance of high strength concrete-filled steel columns exposed to fire

1998 ◽  
Vol 25 (6) ◽  
pp. 975-981 ◽  
Author(s):  
VKR Kodur
Keyword(s):  
Fire Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Experimental Program ◽  
Structural Behaviour ◽  
Steel Columns ◽  
Strength Concrete ◽  
Normal Strength ◽  
Concrete Filling ◽  
Hollow Structural Section

Results from an experimental program on the behaviour of high strength concrete-filled steel hollow structural section (HSS) columns will be presented for three types of concrete filling. A comparison will be made of the fire-resistance performance of HSS columns filled with normal strength concrete, high strength concrete, and steel-fibre-reinforced high strength concrete. The various factors that influence the structural behaviour of high strength concrete-filled HSS columns under fire conditions are discussed. It is demonstrated that, in many cases, addition of steel fibres into high strength concrete improves the fire resistance and offers an economical solution for fire-safe construction.Key words: high strength concrete, steel columns, fire-resistance design, high-temperature behaviour, concrete-filled steel columns.

Bond Strength of Reinforcement in High-Strength Concrete

2000 ◽  
Vol 3 (3) ◽  
pp. 245-253 ◽  
Author(s):  
P. Mendis ◽  
C. French
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Development Length ◽  
Normal Strength Concrete ◽  
Empirical Relationships ◽  
Strength Concrete ◽  
The World ◽  
Current Design ◽  
Normal Strength

The use of high-strength concrete is becoming popular around the world. The american code, ACI 318–95 is used in many countries to calculate the development length of deformed bars in tension. However, current design provisions of ACI 318–95 are based on empirical relationships developed from tests on normal strength concrete. The results of a series of tests on high-strength concrete, reported in the literature, from six research studies are used to review the existing recommendations in ACI 318–95 for design of splices and anchorage of reinforcement. It is shown that ACI 318–95 equations may be unconservative for some cases beyond 62 MPa (9 ksi).

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