scholarly journals Life Cycle Assessment of Warm Mix Asphalt with Recycled Concrete Aggregate

Author(s):  
Daniela L. Vega A. ◽  
Martinez A. Gilberto ◽  
Joao M. O. dos Santos
Author(s):  
Farhad Reza ◽  
W. James Wilde ◽  
Bernard Izevbekhai

Conservation and reuse of resources are important aspects of sustainability. It is common practice in the U.S. to crush old concrete pavements at the end of their service lives into recycled concrete aggregate and then reuse them in the base course of new pavements. It is not, however, common to use the recycled concrete aggregate (RCA) in the new concrete pavement itself. This paper examines the sustainability and, in particular, the economics of using RCA in the construction of new concrete pavements. Life cycle cost analyses were performed for various hypothetical pavement construction scenarios including RCA both in the base and in the concrete layer and compared with conventional options. If RCA is simply substituted for natural aggregate in a concrete mixture, the concrete is likely not to perform as well as a concrete made without RCA. This can be compensated for by decreasing the water–cement ratio and/or increasing the cement content. Despite this fact, the results of the life cycle cost analyses show that it can be very economical to use RCA in new concrete pavement construction. As the natural aggregate used for concrete may be more expensive than the natural aggregate used for base courses, it may make good economic sense to substitute RCA for natural aggregate in concrete. Life cycle analysis also shows that concrete with RCA may have better environmental impact.


2021 ◽  
Vol 13 (8) ◽  
pp. 4245
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas

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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