scholarly journals Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 803
Author(s):  
Carlos Hoffmann Sampaio ◽  
Bogdan Cazacliu ◽  
Weslei Ambrós ◽  
Márcio Kronbauer ◽  
Rejane Tubino ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Coarse Aggregate ◽  
Size Range ◽  
High Strength ◽  
Gravity Concentration ◽  
Strength Concrete ◽  
Ordinary Concrete ◽  
Very High

This paper presents a physical characterization for the recycling into new concretes of three comminuted concretes: C16/20 (“ordinary concrete”), C50/60 (“high strength concrete”), and C70/85 (“very high strength concrete”). The top size of the crushed concretes was 19.1 mm and the size range was 4.75 to 19.1 mm. The characterization was carried out with coarse aggregate liberation, to be prepared and concentrated in a gravity concentration process. The density distribution of the coarse aggregate, cement paste, and sand was carried out in different size ranges (4.75/19.1 mm; 4.75/8.0 mm; 8.0/12.5 mm; and 12.5/19.1 mm) for the three concretes studied. The form factor of the samples, as well as the porosity determination of particles in different density ranges, are presented. The obtained results indicate that the coarse aggregate liberation was more intensive for the low resistance concrete (C16/20), but a reasonable coarse aggregate recovery is possible for all concretes.

Chloride Penetration through Cracks in Concrete with Various Mixing Properties

2011 ◽  
Vol 378-379 ◽  
pp. 723-726
Author(s):  
In Seok Yoon
Keyword(s):  
High Strength Concrete ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
High Strength ◽  
Chloride Penetration ◽  
Mixing Properties ◽  
Strength Concrete ◽  
Ordinary Concrete ◽  
Coarse Aggregates ◽  
Micro Cracks

The purpose of this study is to identify and quantify the effect of the mixing features of concrete such as size of coarse aggregate, high strength and steel fiber reinforcement on chloride penetration through micro-cracks. In examining the effect of size of coarse aggregate on chloride penetration through cracks, the cracks should not impact on chloride penetration directly, although small size of coarse aggregate can lead to complicated micro-cracks in concrete. On the contrary, chloride should easily penetrate through micro-cracks concentrated at the surface of coarse aggregates. In examining the effect of high strength concrete on chloride penetration through cracks, high strength concrete has an excellent performance to resist with chloride penetration. If cracks are generated in high strength concrete, however, its performance is reduced up to the level of ordinary concrete.

Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth
Keyword(s):  
Frost Resistance ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Factors Influencing

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.

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

The Possibility of Using Boiler Slag as Coarse Aggregate in High Strength Concrete

2017 ◽  
Vol 22 (5) ◽  
pp. 1816-1826 ◽  
Author(s):  
Piotr Smarzewski ◽  
Danuta Barnat-Hunek ◽  
Walery Jezierski
Keyword(s):  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Strength Concrete
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