THE EFFECTS OF RATTAN (Calamus rotang . L) NATURAL FIBRE REINFORCING MATERIAL ON THE STRENGTH OF CONCRETE BEAMS AND SLABS

Abstract

In this research, fibres produced from the stem of a naturally occurring plant known as rattan, were added to concrete to produce beams of different spans and slabs of different thicknesses; and their flexural strengths were tested. The spans of the concrete beams tested were 300 mm, 450 mm, 600 mm, and 750mm while the thicknesses for slabs were 50mm, 75mm and 100mm. A second set of beams and slabs of the same spans and thicknesses were also cast but without any additive while a third set were cast with 10mm steel reinforcement. The beams and slabs without any additives served as control. The results of the experiment showed that the modulus of rupture was greatest for the fibred beam with 300mm span and least for 600mm beam, greatly decreasing as the span increased. But at 750mm, the modulus of rupture value increased with an increase in the span. This was also true of the control beam but for the beam with steel reinforcement the modulus of rupture was least for the 300mm span and greatest for the 750mm span. For the 300mm beam with fibres the modulus of rupture at 8.76MN/m2, was about 13.5% higher than that of the control. The modulus of rupture for the beam with steel reinforcement was only 12% higher than that of the beam with rattan fibres. For the 450mm span beam the modulus of rupture of the beam with fibres was 19.9% greater than the control. For the 600mm and 750mm span beams, the modulus of rupture for the beams with fibre were 19% and 15.3% higher than the respective controls. In the case of slabs, 50mm, 75mm and 100mm thick slabs gave optimal flexural strengths of 11.30MN/m2, 9.99MN/m2 and 9.67MN/m2 respectively for 0.04% fibre content representing 46.9%, 30.5% and 25.9% increase respectively over their control values. Also Crack pattern shows that fibre will hold the slab together even if there is deformation