Flexural behavior of epoxy-modified reinforced concrete beams

• Published in: Innovative infrastructure solutions : the official journal of the Soil-Structure Interaction Group in Egypt (SSIGE) 2021-12, Vol.6 (4), Article 182
• Main Authors: Beshara, Fouad B. A., Hammad, Youssef M. H., El-Mandouh, Mahmoud A., El-Maula, Ahmed S. Abd
• Format: Article
• Language: English
• Subjects: Case Study; Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; Foundations; Geoengineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics
• ISSN: 2364-4176; 2364-4184
• DOI: 10.1007/s41062-021-00554-5

Epoxy-modified concrete (EMC) is made by partially replacing ordinary Portland cement with epoxy by weight. The present investigation is concerned with the behavior and performance of epoxy-modified reinforced concrete (EMRC) beams in flexure under monotonic static loading. Comprehensive experimental studies were carried out on ten simply supported under-reinforced EMRC beams to study the response characteristics and failure mechanisms. The main tested variables are epoxy weight ratio, tension steel ratio, and un-bonded lengths of main reinforcement bars. All beams were constructed from EMC with 70 MPa as compressive strength. Seven beams were reinforced with steel ratio ( ρ  = 1.1%) and the other three beams were reinforced by steel ratio ( ρ  = 1.97%). Two different epoxy weight ratios as 5% and 10% were used. To investigate the effect of epoxy inclusion on beams with poor bond conditions, four beams were tested with un-bonded lengths ( L ub ) of bottom reinforcement as 200 mm and 400 mm at mid-span. The results show that EMRC beams with higher epoxy content create cracks that are less propagated, widened, and spread. The ultimate load capacity was increased by 3.6% and 7.3% when using 5% and 10% epoxy weight ratio for beams with steel ratio 1.1%, respectively, while it was 2.3% and 5.2% for steel beams with ratio of 1.97%. The inclusion of epoxy enhances the performance of concrete beams with poor bond conditions. Furthermore, nonlinear finite element analysis was used to forecast the load–deflection curves of the tested beams. Finally, a proposed design equation for predicting the ultimate moment capacity of EMRC beams was developed, and a comparison with the ACI Code was conducted. Finite element and design experiments projected outcomes that were highly associated with measured results.