Optimisation of recycled concrete aggregates for cement-treated bases by response surface method

• Published in: The international journal of pavement engineering Vol. 24; no. 1
• Main Authors: Chiranjeevi, Kondeti, Kumar, Doma Hemanth, Srinivasa, Anil Sagar, Ravi Shankar, A. U.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 06-12-2023; Taylor & Francis LLC
• Subjects: Aggregates; Ball-milling; Cement; cement treated bases; Compressive strength; Concrete aggregates; Durability; Flexural strength; Highway construction; Mechanical properties; Microstructural analysis; Modulus of elasticity; Natural resources; recycled concrete aggregate; Recycled materials; response surface method; Response surface methodology; Road construction; sustainability; Tensile strength
• ISSN: 1029-8436; 1477-268X
• DOI: 10.1080/10298436.2023.2179051

Sustainability is a primary concern that needs to be addressed since infrastructure development requires significant natural resources. Using Recycled Concrete Aggregates (RCA) for road construction has numerous benefits in saving natural resources and the environment. In the present investigation, the demolition waste is being used for road construction, partially/fully replacing natural aggregates. The Cement Treated Recycled Concrete Aggregate (CTRCA) specimens were prepared at 3%, 5%, and 7% cement with various blends of RCA and Natural Coarse Aggregates (NCA) ranging from 0 to 100%. The strength characteristics in terms of Unconfined Compressive Strength (UCS), Flexural Strength (FS), Elastic Modulus, Indirect Tensile Strength (ITS) and durability tests were conducted on cured samples. Microstructural analysis using Scanning Electronic Microscope (SEM) revealed that the pores and cracks in the old mortar have a detrimental influence on the mechanical properties of CTRCA mixes. However, Energy Dispersive Spectroscopy (EDS) and durability tests have shown positive results. The Response Surface Method (RSM) was utilised to optimise the RCA and cement content in CTRCA mixes. The research resulted in the maximum possible RCA of up to 70% with a cement content of 5.8%, which met the Indian Road Congress (IRC) specifications for Cement Treated Bases (CTB).