Flexural Response of Concrete Specimen Retrofitted with PU Grout Material: Experimental and Numerical Modeling

Sadi Ibrahim Haruna; Yasser E Ibrahim; Zhu Han; Abdulwarith Ibrahim Bibi Farouk

doi:10.3390/polym15204114

Flexural Response of Concrete Specimen Retrofitted with PU Grout Material: Experimental and Numerical Modeling

Polymers (Basel). 2023 Oct 17;15(20):4114. doi: 10.3390/polym15204114.

Authors

Sadi Ibrahim Haruna^{1

2}, Yasser E Ibrahim¹, Zhu Han², Abdulwarith Ibrahim Bibi Farouk²

Affiliations

¹ Engineering Management Department, College of Engineering, Prince Sultan University, Riyadh 11586, Saudi Arabia.
² School of Civil Engineering, Tianjin University, Tianjin 300072, China.

Abstract

Polyurethane (PU) composite is increasingly used as a repair material for civil engineering infrastructure, including runway, road pavement, and buildings. Evaluation of polyurethane grouting (PUG) material is critical to achieve a desirable maintenance effect. This study aims to evaluate the flexural behavior of normal concrete repaired with polyurethane grout (NC-PUG) under a three-point bending test. A finite element (FE) model was developed to simulate the flexural response of the NC-PUG specimens. The equivalent principle response of the NC-PUG was analyzed through a three-dimensional finite element model (3D FEM). The NC and PUG properties were simulated using stress-strain relations acquired from compressive and tensile tests. The overlaid PUG material was prepared by mixing PU and quartz sand and overlayed on the either top or bottom surface of the concrete beam. Two different overlaid thicknesses were adopted, including 5 mm and 10 mm. The composite NC-PUG specimens were formed by casting a PUG material using different overlaid thicknesses and configurations. The reference specimen showed the highest average ultimate flexural stress of 5.56 MPa ± 2.57% at a 95% confidence interval with a corresponding midspan deflection of 0.49 mm ± 13.60%. However, due to the strengthened effect of the PUG layer, the deflection of the composite specimen was significantly improved. The concrete specimens retrofitted at the top surface demonstrated a typical linear pattern from the initial loading stage until the complete failure of the specimen. Moreover, the concrete specimens retrofitted at the bottom surface exhibit two deformation regions before the complete failure. The FE analysis showed good agreement between the numerical model and the experimental test result. The numerical model accurately predicted the flexural strength of the NC-PUG beam, slightly underestimating Ke by 4% and overestimating the ultimate flexural stress by 3%.

Keywords: concrete; finite element analysis; flexural strength; polyurethane; polyurethane grout material.

Grants and funding

This research was funded by the Natural Science Foundation of China (No. 51708314) and the APC was funded by the Structures and Materials Laboratory (S&M Lab) of the College of Engineering, Prince Sultan University, Riyadh, Saudi Arabia.