Flexural behavior of reinforced concrete partially restrained slab specimens subjected to fire flame

الملخص EN

This research deals with the flexural behavior of partially end restrained slabs subjected to burning by fire flame.

The investigation is based on casting and testing 16 reduced scale (600 × 600 × 40 mm) reinforced concrete slab specimens.

Two concrete mixes with design 28 days compressive strengths of (30 and 38 MPa) were adopted.

Two steel ratios of (0.005, 0.009) were used.

The specimens were exposed to fire flame temperature levels of (400, 500 and 600°C) at the lower surface of the slab specimens with exposure duration of one hour, then after 24 hours ; they were tested in flexure to failure under uniformly distributed load while they are partially edge restrained against lateral and rotational movements.

It was found from the results that the values of ultimate load capacity, decreased for all specimens after exposing to fire flame.

The residual ultimate load capacity for specimens burnt at temperatures of (400 and 500°C) was higher than that for specimens burnt at 600°C.

At temperature around 600°C and for steel ratios of (0.005 and 0.009), the percentages of residual ultimate load ranged between (85 and 87 %) respectively.

The residual compressive strength at 600°C was about (63 %).

However the residual modulus of rupture was in the range of (47 and 51 %) and the residual modulus of elasticity ranged between (29 and 26 %) at 600 ºC.