Title

Evaluation of Recementation Reactivity of Recycled Concrete Aggregate Fines

Authors

Authors

J. Kim; B. Nam; Z. Behring;B. Al Muhit

Comments

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Abbreviated Journal Title

Transp. Res. Record

Keywords

STRENGTH; MORTAR; Engineering, Civil; Transportation; Transportation Science & Technology

Abstract

The use of recycled concrete aggregate (RCA) as a drainage material in exfiltration trenches and base and subbase layers is becoming increasingly common. During crushing, stockpiling, transporting, and placing, however, RCA may produce fines that could recement and clog the pavement drainage system. Many previous studies indicated that not only the structural capacity but also drainage of pavement subsurface layers can be greatly affected by the properties and gradation of the aggregate used. This study evaluated the recementation reactivity of RCA fines that could eventually impair drainage performance. RCA fines passing the No. 200 sieve (less than 75 pm) were produced through the simulation of an in-place aggregate abrasion process, and cement paste cylinders were cast with complete replacement of cement with RCA fines. The hydration properties of the paste samples with RCA fines were evaluated by means of heat of hydration, pH variation, and Vicat needle penetration in their early age. Compressive strength tests and petrographic examinations such as scanning electron microscopy, energy dispersive X-ray, and X-ray diffraction were also performed to mechanically and chemically verify the recementation reactivity of the hardened paste with RCA fines. Test results demonstrated that recementation of RCA fines was modest, and therefore the compressive strength of the paste specimens with RCA fines was minimal compared with that of ordinary cement paste specimens. The microstructural and chemical composition analyses also indicated that the recementation reactivity of RCA fines was negligible.

Journal Title

Transportation Research Record

Issue/Number

2401

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

44

Last Page

51

WOS Identifier

WOS:000339367600006

ISSN

0361-1981

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