Exploring the combined impact of coarse linz-donawitz slag and basalt fiber on the properties of concrete

This study explores the combined effects of incorporating coarse Linz-Donawitz (LD) slag aggregate and basalt fiber (BF) on concrete’s mechanical and durability properties. Concrete specimens with varying proportions of these materials were prepared and subjected to standard testing methods to evaluate their strength properties, including compressive strength (CS), split tensile strength (STS), and flexural strength (FS), as well as durability properties such as water absorption (WA), electrical resistivity (ER), carbonation depth (CD), and freeze–thaw resistance (FTR). In addition, slump and non-destructive tests (NDT) such as ultrasonic pulse velocity (UPV) and rebound hammer (RH) were also performed. Results indicated that substituting 50% of natural coarse aggregate (NCA) with coarse LD slag aggregate (LDSA) and adding 0.45% BF yielded optimal concrete properties. The results demonstrated notable increases in mechanical properties, with CS, STS, FS, and RHN improving by 32.25%, 34.06%, 36.52%, and 11.36%, respectively, after 28 days of curing compared to standard concrete (SC). Durability tests showed similar enhancements, with UPV and ER increasing by 8.16% and 39.63%. Meanwhile, WA and CD were reduced by 15.71% and 29.70%, respectively. Notably, freeze–thaw resistance (FTR) was also reported least mass and strength loss compared to SC. These improvements are attributed to LDSA’s pozzolanic activity, which enhances concrete density, and BF’s ability to improve crack resistance and stress distribution. The combination of LDSA and BF not only strengthens concrete properties but also fosters sustainable construction by increasing resistance to environmental challenges and provides valuable eco-friendly options for modern construction practices.