Influence of the incorporation of glass fiber and steel on the physical and mechanical properties of concrete

In reinforced concrete construction, materials are subjected to high stresses, which can generate deformations and cracks, affecting their performance and functionality. The objective of this study was to evaluate the impact of the incorporation of glass fiber (GF) and the combination of GF with steel fiber (SF) on the physical and mechanical properties of concrete. Standard concrete (SC) and GF mixtures were prepared at doses of 0.1%, 0.3%, 0.6% and 0.9%, as well as hybrid mixtures of GF with SF at doses of 0.08%, 0.16%, 0.24% and 0.32%. The GF had lengths between 100 and 120 mm, while the SF measured 60 mm. A 1% plasticizer and a water/cement ratio of 0.71 were used. The mechanical properties of the hardened concrete were evaluated at 7, 14 and 28 days in terms of compressive, tensile and flexural strength. The results indicated that the use of GF reduces the workability compared to hybrid mixes but maintains the unit weight and air content within the normative parameters. In addition, 0.3% GF content increased strengths by up to 11%, while the combination of 0.3% GF with 0.32% SF showed improvements of up to 19% in all properties evaluated at 28 days. The combination of GF and SF has a positive effect on the mechanical properties of concrete, allowing its use in various structural applications, such as pavements, slabs, precast elements, columns and beams.