Strengthening and rehabilitating RC beams using ferrocement containing waste tires chips.

Subjecting structural members to loads greater than their designed bearing capacity requires them to be strengthened or rehabilitated. One method of doing this is the addition of a ferrocement layer to the defective member. This paper thus aimed to investigate strengthening or rehabilitation ability of the ferrocement layer reinforcing with chopped rubber tire rather than standard fibres on RC beams. Five reinforced concrete beams of dimensions 750 × 150 × 200 mm were thus cast and cured, and these samples were then divided out. One beam was left as a reference, one beam was strengthened using wire mesh and ordinary cement mortar, and the others were strengthened using wire mesh and rubber chip reinforced mortar. One beam was subjected to 30% of its ultimate load before strengthening with a rubber chip reinforced ferrocement layer, while the other was subjected to 60% of its ultimate load before reinforcement. The results indicate that the addition of chips to the cement mortar of the ferrocement layer offered noticeable increases in failure load and deflection, of 55.6% and 13.6% respectively, as compared to those of beams strengthened with a ferrocement layer without such chips. As compared to the reference beam, without a ferrocement layer, the beam subjected to 30% of its bearing strength before reinforcement not only regained its first crack and failure load capacity on addition of a rubber chip-reinforced ferrocement layer, it also showed improvement by 64.8% and 72.8% in these measures, respectively. Such reinforcement also increased ductility compared to the reference beam by increasing the deflection at first crack and failure rate by 123% and 40%, respectively. Strengthening the beam subjected to 60% of its bearing strength using a rubber chip-reinforced ferrocement layer allowed it to not only regain its first crack and failure load capacity but also to improve these by 38.9 and 59.2%, respectively. The ductility of the beam was again improved based on am increase in the deflection to first crack and failure rate, by 66.7% and 29.4%, respectively. [ABSTRACT FROM AUTHOR]