Strengthening and repair of one-way and two-way self-compacted concrete slabs using near-surface-mounted carbon-fiber-reinforced polymers

Abstract

The effectiveness of near-surface-mounted carbon-fiber-reinforced polymers on strengthening and repair of self-compacted concrete slabs was investigated experimentally and numerically. Twenty slabs were cast (10 one-way and 10 two-way) and tested under four-point load. Strengthening and repair effectiveness was investigated on slabs using near-surface-mounted carbon-fiber-reinforced polymer strips with straight and inclined orientation. Repair was performed on eight slabs using near-surface-mounted carbon-fiber-reinforced polymer strips with an orientation based on the best cost/capacity ratio, with two preloading levels: 35% and 50% of the ultimate load of the control slab. The results showed that using near-surface-mounted carbon-fiber-reinforced polymers increases the ultimate strength of one-way strengthened self-compacted concrete slabs (45%–163%) for both strip orientation, with the straight orientation performing better. Also, the cracking load and stiffness increased, while deflection decreased. The increase in ultimate strength for strengthened two-way slabs was 15% to 17%. The ultimate deflection and toughness of the two-way strengthened slabs increased 43% and 34%, respectively. Using near-surface-mounted carbon-fiber-reinforced polymers restored the load capacity of repaired one-way and two-way slabs but was more effective for one-way slabs. The repaired one-way slabs regained up to 223% of the control slabs’ ultimate strength, with a significant increase in stiffness (296%). The repaired two-way slabs regained up to 116% of the control slabs’ ultimate strength. The strength was higher in the case of the 50% preload compared to 35% preload. The finite element model shows somehow a reasonable capability of predicting the experimental behavior with a gap in terms of the stiffness and the maximum load.

Shear performance of reinforced concrete beams strengthened in shear using NSM bars and reinforced HSC layers

“…Due to EB-FRP problems, using NSM-FRP shear strengthening became an attractive solution to overcome the limitations of the EB technique. Many researchers [36][37][38][39][40][41][42][43] investigated using NSM-FRP to increase RC structures' performance under compression, flexure, and shear. For instance, the flexural and shear capacity was enhanced by increasing the amount of FRP, orienting it in the suitable direction, and FRP properties.…”

Effect of Near-Surface Mounted Bars on the Structural Behavior of One-Way Rc Slab

“…Using NSM reinforcement can raise the flexural capacity, stiffness and reduces the crack width more than using externally bonded (EB) reinforcement. Experimentally and numerically study on repairing and strengthening of selfcompacted concrete slabs was presented by Ashteyat et al, 2019. The effectiveness of straight and inclined NSM carbon-fiber-reinforced polymers CFRP on the strengthening and repairing of self-compacted concrete slabs.…”

Experimental and numerical assessment of the flexural behaviour of semi-precast-reinforced concrete slabs

“…The concrete-to-concrete bonding is influenced by many factors. The surface texture/roughness, initial moisture condition and curing conditions are the significant factors that affect the bonding behaviour of concrete (Asad et al, 2019; Ashteyat et al, 2019; Julio et al, 2004; Momayez et al, 2005; Thamboo and Dhanasekar, 2015). Therefore, proper surface treatment should be carried out between the concrete interfaces to develop adequate bonding for better performance of these slab systems.…”