International Concrete Abstracts Portal

Title: Characteristics of Concrete with High Volume Coarse Recycled Concrete Aggregate

Author(s): Anto Sucic and Medhat H. Shehata,

Publication: Special Publication

Volume: 314

Issue:

Appears on pages(s): 1-16

Keywords: Durability, Recycled Materials, Recycled Concrete Aggregate, Sustainability

Date: 3/1/2017

Abstract:
Consideration of using high volume of Recycled Concrete Aggregate (RCA) in conventional concrete applications is rare due to the physical properties of RCA and its corresponding drawbacks. In the rare instance where RCA is utilized, replacement levels typically do not exceed 15-20% in order to minimize on the drawbacks. To take another approach, this paper presents results from a study aimed at maximizing the RCA replacement levels, while making only minor adjustments in mix design, to achieve both equivalent strength and durability performance of RCA concrete to their virgin aggregate counter parts. In order to investigate higher replacement levels, 15 MPa concrete criteria were followed to produce a high-volume, low-risk concrete readily produced in the ready-mix industry. Concrete specimens were tested for compressive strength, drying shrinkage, and effects of released alkalis from RCA on triggering disruptive expansion, if used with sand that marginally meets the alkali-silica expansion limit. Through modifications in mix design, the drawbacks of RCA (reduced strength, increased drying shrinkage, and promoting ASR potential) were successfully mitigated at coarse RCA replacement levels up to 100%.