EFFECT OF RECYCLED CONCRETE AGGREGATE, AIR ENTRAINING ADMIXTURE AND MAXIMUM AGGREGATE PARTICLE SIZE ON THE BEHAVIOR OF CONCRETE UNDER FREEZE-THAW CYCLES

2021 ◽  
Vol 16 (2) ◽  
pp. 217-233
Author(s):  
Yeşim Tarhan ◽  
Remzi Şahin
Keyword(s):  
Capillary Permeability ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Particle Sizes ◽  
Recycled Concrete Aggregate ◽  
Nacl Solution ◽  
Aggregate Particle ◽  
Freeze Thaw ◽  
Concrete Elements ◽  
Parking Facilities

ABSTRACT This article presents freeze-thaw (F/T) resistance of concrete containing recycled concrete aggregate (RCA). RCA percentages of 15%, 30%, 45%, and 60% were replaced by natural aggregate. Air entraining admixture (AEA) with three different ratios (0.06%, 0.13%, and 0.20%) were used and three different maximum aggregate particle sizes (dmax = 16 mm, 22.4 mm and 31.5 mm) were selected. F/T resistances of the concretes were determined through the measurement of scaling on the surfaces of the samples placed in 3% NaCl solution in pursuance of TS CEN/TS 12390-9. It was observed that the compressive strength of the concretes decreased by 20% on average compared to the control samples with the increase in the amount of RCA. However, it was determined from the experiments that the use of RCA increases the F/T resistances of the concretes as it provides extra voids in the concrete and decreases capillary permeability. Within the limits of this study, dmax = 22.4 mm, RCA = 45% and AEA = 0.13% are recommended as the optimum values for F/T resistance of the concrete. It is also recommended to use RCA in pavement applications including roadways, highways, parking facilities, and other non-structural concrete elements subjected to severe winter conditions.

scholarly journals Physical, Deformation, and Stiffness Properties of Recycled Concrete Aggregate

2021 ◽  
Vol 13 (8) ◽  
pp. 4245
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas
Keyword(s):  
Recycled Concrete ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Test Results ◽  
Recycled Concrete Aggregate ◽  
Granulometric Analysis ◽  
Stiffness Properties ◽  
Grain Distribution ◽  
Natural Aggregates ◽  
Critical Reduction

The construction sector is currently struggling with the reuse of waste originating from the demolition and modernization of buildings and roads. Furthermore, old buildings are gradually being replaced by new structures. This brings a significant increase of concrete debris to waste landfills. To prevent this, many studies on the possibilities of recycling concrete, known as recycled concrete aggregate (RCA), have been done. To broaden the applicability of reused concrete, an understanding of its properties and engineering behavior is required. A difficulty in sustainable, proper management of RCA is the shortage of appropriate test results necessary to assess its utility. For this reason, in the present study, the physical, deformation, and stiffness properties of RCA with gravely grain distribution were analyzed carefully in the geotechnical laboratory. To examine the mentioned properties, an extensive experimental program was planned, which included the following studies: granulometric analysis, Proctor and oedometer tests, as well as resonant column tests. The obtained research results show that RCA has lower values of deformation and stiffness parameters than natural aggregates. However, after applying in oedometer apparatus repetitive cycles of loading/unloading/reloading, some significant improvement in the values of the parameters studied was noticed, most likely due to susceptibility to static compaction. Moreover, some critical reduction in the range of linear response of RCA to dynamic loading was observed.

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