Reducing environmental impact by Optimizing sustainable concrete mixes using Portland slag cement and recycled aggregate

¹ Department of Applied Sciences, New Horizon College of Engineering, Bangalore, India.
² Department of Electronics and Communication Engineering, MLR Institute of Technology, Hyderabad, Telangana, India.
³ Lovely Professional University, Phagwara, India
⁴ Department of Information Technology, Gokaraju Rangaraju Institute of Engineering and Technology, Bachupally, Hyderabad, Telangana, India.
⁵ Lloyd Institute of Engineering & Technology, Greater Noida, Uttar Pradesh 201313, India.

^* Corresponding Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 3 March 2026

Abstract

Concrete is one of the major component used in construction of structures, using recycled materials is becoming essential for environmentally friendly buildings. The purpose of this work is to determine if concrete mixes that comprise Portland Slag Cement (PSC) and Recycled Aggregates (RA) are suitable for use in sustainable construction by examining their mechanical characteristics. Fifteen mix types were evaluated using normal-strength concrete featuring a 0.45 water-to-cement ratio and a compressive strength of 35 MPa. PSC and RA replacement levels ranged from 0% to 50% and 0% to 100%, respectively. A thorough intensive test was performed, which included measurements of the strengths and durability for seven and twenty eight days, as well as analyses of the modulus of elasticity and stress-strain curve. The findings show that RA reduced compressive strength by 10% and modulus of elasticity by 20% when Natural Aggregate (NA) was completely replaced with it. In the presence of RA, however, a 25% substitution of PSC for Ordinary Portland Cement (OPC) prevented the compressive strength from decreasing to 0.92% and raised the modulus of elasticity by 3.7%. The ideal mix, which is composed of 75% OPC, 25% PSC, and 50% RA, greatly improves the mechanical qualities of concrete and is advised for use in reinforced concrete applications because of its possible structural and environmental advantages.