Sustainable construction solutions: The role of sugar factory lime waste-activated slag in high-performance concrete
Hadi Bahmani, Davood Mostofinejad
Abstract
This pioneering research aims to develop high-performance concrete (HPC) using waste lime from sugar factories to activate slag. The study explores the transformative effects of high-temperature treatment on sugar factory lime waste and its potential to enhance slag activation, representing a novel approach in sustainable construction materials. The newly formulated HPC was rigorously compared with traditional counterparts made from calcium oxide-activated slag and calcined dolomite. A comprehensive series of tests were conducted at 28 days, assessing critical performance metrics, including compressive strength, four-point bending strength, tensile strength, and water absorption. Microstructural analysis was performed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDAX), and Fourier Transform Infrared Spectroscopy (FTIR). The results revealed that samples activated with 10 % sugar factory lime waste achieved a compressive strength of approximately 80 MPa, rivaling samples activated with 10 % calcium oxide. These lime-activated samples also demonstrated outstanding tensile and bending strengths of 5.6 MPa and 6.6 MPa, respectively—the highest recorded in this study. The microstructural analysis indicated a dense microstructure with an elevated Si/Al ratio and significant geopolymerization. The low water absorption rate of 2.1 % highlighted the reduced porosity of this innovative geopolymeric matrix. This research is the first to investigate the high-temperature treatment of sugar factory lime waste for slag activation in HPC. The findings suggest that incorporating 10 % waste lime significantly lowers the climate change impact index to 397.6 kg CO 2 eq—12 % less than samples with 30 % calcium oxide and 7 % lower than those with 30 % dolomite. Using sugar factory waste lime enhances mechanical properties and promotes environmental sustainability, presenting a compelling alternative that excels in both performance and ecological benefits.