Investigation of axial compressive behavior of reinforced concrete columns using Recycled Coarse Aggregate and Recycled Asphalt Pavement aggregate

Abstract

The axial compressive behavior of fifteen reinforced concrete columns that were constructed from four types of aggregates: Natural Aggregate (NA), Recycled Asphalt Pavement (RAP), Recycled Coarse Aggregate (RCA), and RAP-RCA were studied experimentally and theoretically. The NA was replaced by RAP and RCA at five replacement levels: 20%, 40%, 60%, 80% and 100% by the total weight of NA. In addition of combining RAP and RCA in the same mixes with replacement levels of: 20% RAP-80% RCA; 40% RAP-60% RCA; 60% RAP-40% RCA; and 80% RAP-20% RCA. The axial compressive behavior of the columns was studied through reporting the ultimate load values and the crack propagation during static tests. The experimental axial capacity of the columns was compared with the theoretical values determined by ACI and Japanese codes. The experimental results showed that there was a reduction in the axial capacity of columns when the RAP, RCA, and RAP-RCA contents increased. However the calculated theoretical values were more conservative comparing to the experimental values. This provides a very positive indication that the RAP, RCA, and RAP-RCA columns can be used in the structures safely and the RAP-RCA combination is a promising technique.