A simplified testing approach for recycled aggregate

![CDATA[Environmental impacts caused by construction and demolition (C&D) activities are inevitable. Concrete and masonry waste is being recycled as recycled aggregate (RA) and introduces back to the construction cycle and forms a closed-loop system. The current popularity of RA utilization in concrete applications is limited. The high variations of RA properties are a major hurdle for the popularity for the use of RA in construction applications. This paper simplifies RA testing procedures. Eleven physical and mechanical prope1iies of aggregate are being investigated: (I) uncompacted bulk density ; (2) compacted bulk density; (3) particle density; (4) water absorption; (5) aggregate crushing value; (6) dry strength; (7) wet strength; (8) contaminant; (9) weak particle; (10) flakiness index; and (11) particle shape. The experiments conducted are based on Australian Standard 1141 [I] and HB 155 [2]. Eleven RA samples collected from C&D sites and centralised recycling plants located in Brisbane, Gold Coast and Sydney, Australia are used. The simplified testing procedures are established by constructing a regression analysis among different aggregate tests. From the results, it is refined three groups of tests: i) Group I (density, water absorption, strength and contaminant); ii) Group II (weak particle); and iii) Group III (shape). By implementing the prediction equations, about 63.6% reduction of test has been achieved with full understanding of the quality of RA. A reduced time of testing can test the properties of RA at the source locations and help bring the potential achievement of RA as high-grade concrete applications by without averaging the RA quality in the centralized recycling plants.]]