High-Strength Concrete Containing Recycled Coarse Aggregate Subjected to Elevated Temperatures

2019 ◽  
Vol 55 (5) ◽  
pp. 1477-1494 ◽  
Author(s):  
P. Pliya ◽  
D. Cree ◽  
H. Hajiloo ◽  
A.-L. Beaucour ◽  
M. F. Green ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Coarse Aggregate ◽  
High Strength ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

Estimation of Compressive Strength of Recycled Aggregate High Strength Concrete Using Ultrasonic Pulse Velocity

2014 ◽  
Vol 605 ◽  
pp. 147-150
Author(s):  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
Yong Taeg Lee
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66

scholarly journals Dynamic Tensile Properties and Energy Dissipation of High-Strength Concrete after Exposure to Elevated Temperatures

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5313 ◽  
Author(s):  
Nao Lv ◽  
Hai-bo Wang ◽  
Qi Zong ◽  
Meng-xiang Wang ◽  
Bing Cheng
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
High Temperatures ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Coarse Aggregate ◽  
High Strength ◽  
Dynamic Tensile Strength ◽  
Strength Concrete ◽  
Propagation Law

In view of the devastating outcomes of fires and explosions, it is imperative to research the dynamic responses of concrete structures at high temperatures. For this purpose, the effects of the strain rate and high temperatures on the dynamic tension behavior and energy characteristics of high-strength concrete were investigated in this paper. Dynamic tests were conducted on high-strength concrete after exposure to the temperatures of 200, 400, and 600 °C by utilizing a 74 mm diameter split Hopkinson pressure bar (SHPB) apparatus. We found that the quasi-static and dynamic tensile strength of high-strength concrete gradually decreased and that the damage degree rose sharply with the rise of temperature. The dynamic tensile strength and specific energy absorption of high-strength concrete had a significant strain rate effect. The crack propagation law gradually changed from directly passing through the coarse aggregate to extending along the bonding surface between the coarse aggregate and the mortar matrix with the elevation of temperature. When designing the material ratio, materials with high-temperature resistance and high tensile strength should be added to strengthen the bond between the mortar and the aggregate and to change the failure mode of the structure to resist the softening effect of temperature.

Estimation of Compressive Strength of High-Strength Concrete with Recycled Aggregate Using Ultrasonic Pulse Velocity Method

2013 ◽  
Vol 680 ◽  
pp. 226-229 ◽  
Author(s):  
Young Sang Cho ◽  
Sang Ki Baek ◽  
Yong Taeg Lee ◽  
Seung Hun Kim ◽  
Jun Ho Park ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

Recently, many structures which were built about 30 years ago are watched by reconstruction. Demolished concrete is occurred in the process and these quantity increase about 10% more than the preceding year. Although the government have promoted to use recycled coarse aggregate, many registered architects have not use it, because natural aggregate is still cheaper than recycled coarse aggregate's price and they have question about quality of recycled coarse aggregate. In addition, there are no grounds to rely upon compressive strength and ultrasonic pulse velocity method of recycled coarse aggregate when it is used to high strength concrete. In this paper, bases will be adduced to verify applicative possibility of estimation of compressive strength of high-strength concrete with recycled aggregate using ultrasonic pulse velocity method. For this, compressive strength and ultrasonic pulse velocity method tests of 240 high strength concrete specimens with recycled coarse aggregate were performed, and the high strength concrete specimens were tested within the limits such as compressive strength and ultrasonic pulse velocity

A Comparative Study of Compressive Strength of High Strength Concrete by Replacement Ratio of Recycled Coarse Aggregate

2013 ◽  
Vol 680 ◽  
pp. 222-225 ◽  
Author(s):  
Yong Taeg Lee ◽  
Seung Hun Kim ◽  
Seung Ho Lee ◽  
Sang Ki Baek ◽  
Young Sang Cho ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Industrial Development ◽  
Coarse Aggregate ◽  
High Strength ◽  
Construction Waste ◽  
Aggregate Consumption ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregate ◽  
The Government

As the industrial development brings the structures growth, the consumption of the natural aggregate is increasing annually. On the other hand, the amount of the potential aggregate is decreasing with the huge amount of construction waste from the concrete demolition. The annual total amount of natural aggregate consumption estimated 370million tons. And the experts are concerned about the depletion of aggregate which is presumed to be exhausted in 20 years, considering the annual consumption, which is approximately 250million(m³) in construction industry. Along with this issues, the government promotes to use recycled coarse aggregate from the construction waste in consideration of social, economic and environmental aspects. In conclusion, the purpose of this study is to promote to use of recycled coarse aggregate as a future substitute resource and to increase awareness of it as well. This study conducts the experiments by comparing high-strength concrete for the substitution of chosen two companies.

Bond of High Strength Concrete with Recycled Coarse Aggregate and Reinforcing Bar

2014 ◽  
Vol 605 ◽  
pp. 198-201
Author(s):  
Seung Hun Kim ◽  
Yong Taeg Lee ◽  
Seong Uk Hong
Keyword(s):  
Substitution Rate ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Bond Stress ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate ◽  
Reinforcing Bar ◽  
Horizontal Bottom

This study conducted a comparative evaluation of bond behavior according to the steel reinforcing type and substitution rate of recycled coarse aggregate. Mixed as high-strength concrete of design strength 50MPa in order to verify the applicability of recycled coarse aggregate concrete as a structural member. Total of 24 specimens were manufactured with variables of recycled aggregate substitution rate (0%, 30%, 50%, 100%), steel reinforcing arrangement direction (vertical, horizontal top·bottom) and steel reinforcing types (SD400 D16, D19). The specimen was produced according to CSA S802-02 and ASTM 234. specimens using D16 reinforcing, the vertical reinforcing showed similar bond stress regardless of the recycled aggregate substitution rate and slip amount, and for the horizontal reinforcing, the bottom specimen showed similar bond stress as the vertical reinforcing and slip amount. The top specimen showed slightly less bonds tress than vertical and horizontal bottom specimens. This is thought to have been caused by the subsidence of the aggregate. The specimen using D19 reinforcing showed similar bond stress in vertical · horizontal top · bottom, horizontal top reinforcing maximum bond stress, horizontal bottom reinforcing maximum bond stress and showed no difference due to aggregate subsidence like in D16. As the result, Bond stress in this study is larger than 2.0fck, the value proposed by CEB-FIP code. The specimen using D16 reinforcing bar showed 4.5fck and the specimen using D19 reinforcing bar was near 3.9fck. Therefore, since the standard value is satisfied regardless of replacement rate of recycled aggregate, natural aggregate in high strength concrete can be substituted by recycled aggregate.

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