Various recycled steel fiber effect on mechanical properties of recycled aggregate concrete

• Published in: International Journal of Building Pathology and Adaptation 2024-05, Vol.42 (3), p.448-468
• Main Authors: Nath, Amit Deb, Hoque, Md. Ikramul, Datta, Shuvo Dip, Shahriar, Fahim
• Format: Article
• Language: English
• Subjects: Cement; Compressive strength; Concrete aggregates; Concrete mixing; Concrete properties; Construction; Density; Diameters; Economic impact; Flexural strength; Gravity; Mechanical properties; Mixtures; Modulus of elasticity; Natural resources; Recycled materials; Reinforced concrete; Silica fume; Splitting; Steel fibers; Tensile strength
• ISSN: 2398-4708; 2398-4716
• DOI: 10.1108/IJBPA-07-2021-0102

PurposeThe current study mainly focuses on the effect of varying diameter recycled steel fibers (RSF) on mechanical properties of concrete prepared with 25 and 50% of recycled coarse aggregate (RCA) as well as 100% natural aggregate (NA). Two types of RSF with 0.84 mm and 1.24 mm diameter having 30 mm length were incorporated into normal and recycled aggregate concrete (RAC).Design/methodology/approachThe fresh behavior, compressive, splitting tensile, flexural strengths and modulus of elasticity of all the mixes were investigated to evaluate the mechanical properties of RACs. In addition, specimen crack and testing co-relation were analyzed to evaluate fiber response in the RAC.FindingsAccording to the experimental results, it was observed that mechanical properties decreased with the increment replacement of NA by RCA. However, the RSF greatly improves the mechanical properties of both normal concrete and RACs. Moreover, mixes containing 1.24 mm diameter RSF had a more significant positive impact on mechanical properties than mixes containing 0.84 mm diameter RSF. The 0.84 mm and 1.24 mm RSF addition improved the mixes' compressive, splitting tensile and flexural strength by 10%–19%, 19%–30% and 3%–11%, respectively when compared to the null fiber mix. Therefore, based on the mechanical properties, the 1.24 mm diameter of RSF with 25% replacement of RCA was obtained as an optimum solution in terms of performance improvement, environmental benefit and economic cost.Practical implicationsThe practice of RCA in construction is a long-term strategy for reducing natural resource extraction and the negative ecological impact of waste concrete.Originality/valueThis is the first study on the effects of varying size (0.84 mm and 1.24 mm diameter) RSF on the mechanical properties of RAC. Additionally, varying sizes of RSF and silica fume added a new dimension to the RAC.