Strengthening of Reinforced Concrete (RC) Beams using Textile Reinforced Mortars (TRMs)

This study presents the experimental results of fifteen reinforced concrete beams (150 × 100 × 2700 mm): one control beam (without strengthening); one beam strengthened with one layer of textile bonded with epoxy to the tension side of the beam; and the remaining beams were strengthened with one layer, two layers, and three layers of textile bonded with different types of mortar. Two commercially available repair mortars were investigated in addition to one mortar that was prepared in the lab. Most previous studies used special mortar mix, while this study investigated the effectiveness of commercially available mortars without any modifications. Additional U-shaped strips were used on some of the beams as anchorage to strengthen the bond of the textile layers to the concrete surface using two different schemes of the U-shaped textile. Previous research studies concentrated on the end of the beam anchorage, while this study investigated two schemes: one concerning the beam ends and the other focusing on distributing the anchorage over the beam span. The test results indicated that epoxy-bonded textile performed better in terms of strength enhancement with an increase of 33% in the ultimate load compared to the control beam, as the bond was perfect compared to mortar-bonded textile, which resulted in an increase ranging between 15 and 27% depending on the mortar type. However, the ductility or deformability was slightly better with an increase of approximately 25% in the maximum deflections of the beams strengthened with mortar-bonded textiles. The test results also showed that as the number of layers increases, there was no significant increase in strength due to bond failure. When the U- shaped strips were used along with the increasing number of textile fiber layers, gains in flexure strength and ductility were observed. The use of U-shaped strips distributed along the beam was more efficient than only anchoring the ends of the beam. From the results obtained in this study, it is believed that textile-reinforced mortars (TRMs) are a potential solution for the structural upgrading of concrete structures provided that the bond between the textile layer and the concrete surface is maintained.