Laboratory Evaluation of the Use of Cement-Treated Construction and Demolition Materials in Pavement Base and Subbase Applications Alireza Mohammadinia 1 ; Arul Arulrajah 2 ; Jay Sanjayan 3 ; Mahdi M. Disfani 4 ; Myint Win Bo 5 ; and Stephen Darmawan 6 Abstract: Construction and demolition (C&D) materials constitute a major proportion of waste materials present in landfills worldwide. With the scarcity of high-quality quarry aggregates, alternative materials, such as C&D materials, are increasingly being considered as a replacement for traditional road-construction materials, particularly as the sustainable usage of these C&D materials has significant environmental benefits. In this research, an extensive laboratory evaluation was carried out to determine the engineering properties of cement-treated C&D materials. The C&D materials investigated were reclaimed asphalt pavement (RAP), recycled concrete aggregate (RCA), and crushed brick (CB). The geotechnical properties of cement-treated C&D materials were evaluated to assess their performance in pavement base/subbase applications. The effect of curing duration on the strength of the C&D materials was analyzed by conducting unconfined compression strength and repeated load triaxial tests. The RAP required 2% cement (by weight) and either 7 or 28 days of curing to meet the local road-authority requirements, whereas RCA and CB required 4% cement and 28 days of curing. The RAP exhibited the highest strength in all cases, with the same cement content and for the same curing duration, followed by RCA and CB. The resilient moduli of C&D materials increased with an increase in cement content, curing duration, and confining pressure. Humidity curing was found to play an important role in the strength development of cement-treated C&D materials. This study indicates that cement-treated C&D materials are viable construction materials for pavement base/subbase applications. DOI: 10.1061/(ASCE)MT.1943-5533.0001148. © 2014 American Society of Civil Engineers. Introduction Research on the use of commercial and industrial waste materials in civil engineering applications has generated interest in recent years. The reuse of these recycled materials will result in a low carbon footprint, considering that these recycled materials have significant carbon savings compared with extracting virgin quarried materials (Horpibulsuk et al. 2012; Kampala et al. 2013). Construction and demolition (C&D) materials constitute a major proportion of waste materials present in landfills worldwide. The C&D materials have been used in recent years in various civil engineering applica- tions such as roads, embankments, pipe bedding, and backfilling (Rahman et al. 2014b). In Australia, approximately 8.7 million tonnes of recycled con- crete aggregate (RCA), 1.3 million tonnes of crushed brick (CB), and 1.2 million tonnes of reclaimed asphalt pavement (RAP) are stockpiled annually (Arulrajah et al. 2013b). Large quantities of these C&D materials are similarly stockpiled in many urban cities world- wide, with these three C&D materials being the most common waste material. Cement treatment of pavement aggregates is a preferred op- tion in metropolitan roads in major cities worldwide. Approximately 50,000 km of road network is located in metropolitan Melbourne, Australia, in which pavement bases/subbases are constructed with cement-treated aggregates. Traditionally, only high-quality cement- treated crushed rocks obtained from local quarries have been used for cement-treated pavement bases/subbases in Australia, and there- fore, the need to evaluate the performance of cement-treated C&D materials as an alternative pavement-aggregate material. The C&D materials investigated in recent years in pavement and footpath applications are granular stabilization of unbound C&D materials such as RCA (Arulrajah et al. 2012a; Gabr and Cameron 2012; Poon and Chan 2006), CB (Arulrajah et al. 2012b, Rahman et al. 2014a), RAP (Arulrajah et al. 2014b; Hoyos et al. 2011; Puppala et al. 2011; Taha et al. 2002), waste rock (Akbulut and Gurer 2007; Chakrabarti and Kodikara 2007; Imteaz et al. 2012), and waste glass (Arulrajah et al. 2013a; Disfani et al. 2011; Grubb et al. 2006; Wartman et al. 2004). Arulrajah et al. (2014a) investigated the strength parameters and shear-strength responses of C&D materials. Han and Thakur (2013) conducted extensive literature review for geosynthetic-reinforced recycled materials and concluded that geosynthetic-reinforced C&D materials can be successfully used in roadway and railway applications. Research has been undertaken in recent years with cement- treated RAP in pavements (Hoyos et al. 2011; Puppala et al. 2011). Thakur et al. (2012, 2013) conducted medium-scale static-plate loading tests and large-scale cyclic-plate loading tests on geocell- reinforced RAP materials and reported that geocell-reinforced RAP 1 Ph.D. Student, Swinburne Univ. of Technology, Hawthorn, VIC 3122, Australia. E-mail: amohammadinia@swin.edu.au 2 Associate Professor, Swinburne Univ. of Technology, Hawthorn, VIC 3122, Australia (corresponding author). E-mail: aarulrajah@swin.edu.au 3 Professor, Swinburne Univ. of Technology, Hawthorn, VIC 3122, Australia. E-mail: jsanjayan@swin.edu.au 4 Lecturer, Swinburne Univ. of Technology, Hawthorn, VIC 3122, Australia. E-mail: mmiridisfani@swin.edu.au 5 Senior Vice President/Senior Principal, DST Consulting Engineers Inc., Thunder Bay, ON, Canada P7B 5V5. E-mail: mwinbo@dstgroup.com 6 Director, Geotesta Pty Ltd., Notting Hill, VIC 3168, Australia. E-mail: sd@geotesta.com.au Note. This manuscript was submitted on February 14, 2014; approved on June 16, 2014; published online on August 14, 2014. Discussion period open until January 14, 2015; separate discussions must be submitted for individual papers. This paper is part of the Journal of Materials in Civil Engineering, © ASCE, ISSN 0899-1561/04014186(12)/$25.00. © ASCE 04014186-1 J. Mater. Civ. Eng. J. Mater. Civ. Eng. Downloaded from ascelibrary.org by Swinburne University of Technology on 09/29/14. Copyright ASCE. For personal use only; all rights reserved.