Ferrocement Repaired Reinforced Concrete Beams Subjected to Quasi-Static and Cyclic loadings
C. T. E. Lim, K. C. G. Ong, and P. Paramasivam
Appears on pages(s):
beam; concrete (reinforced); crack; epoxy; ferrocement; flexural
strength; repair; strength
The objective of this research was’ to investigate the strength and serviceability, viz cracking behaviour and flexural stiffnesses, of structurally damaged reinforced concrete beams strengthened in flexure by incorporating thin ferrocement laminates reinforced with additional longitudinal bars onto the soffits (tension face) tested under quasi-static and cyclic loadings. Results from seven test beams are discussed. The beams were fabricated and precracked under quasi-static mid-span loading to three levels of damage: 1) flexural failure with crushing of concrete and yielding of tension reinforcements viz 115%, 2) 100% and 3) 90% of their respective theoretical flexural capacities. They were then repaired and strengthened after unloading. Four of the strengthened beams were tested to failure under quasi-static loading while the remaining three were subjected to cyclic sinusoidal loads up to 150,000 cycles. It was found that, under quasi-static loading, the structurally damaged and then repaired and strengthened beams exhibited improved performance compared to their behaviour during the precracking stage. Their performance was comparable to a control beam strengthened in its virgin state showing only marginally larger reopened crack widths. Under cyclic loading however, the presence of a distinct ferrocement/concrete interface at the soffit of the beams resulted in cracking at the interface under repeated loading of high load levels.