THE EFFECTS OF ( rotang . L) NATURAL FIBRE REINFORCING

MATERIAL ON THE STRENGTH OF CONCRETE BEAMS AND SLABS.

BY

ALLI, OLUTAYO OLATUNDUN

CVE/00/7238

AN M. ENG. THESIS PRESENTED IN THE DEPARTMENT OF CIVIL

ENGINEERING,

SCHOOL OF ENGINEERING AND ENGINEERING TECHNOLOGY,

FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE

ONDO STATE, NIGERIA.

SUPERVISOR: DR C. ARUM

JULY, 2011

ABSTRACT

In this research, fibres produced from the stem of a naturally occurring 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

2 2 2 of 11.30MN/m , 9.99MN/m and 9.67MN/m 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. CHAPTER ONE

INTRODUCTION

1.1 Background to the study

Portland cement concrete is a relatively brittle material and generally has little or no useful

tensile strength. When subjected to tensile stresses, unreinforced concrete cracked and

failed, and this led to the introduction of steel reinforcement to overcome this problem

(Berg, 1996).

As a member of a composite system, the reinforcing steel is assumed to carry all

tensile loads. However, natural fibre reinforcing material can be used as a strengthener to

the concrete (Gram, 1983), and this will enhance the performance of the concrete to a

reasonable degree without the use of steel reinforcement.

The plan of government of Nigeria as far back as 1992 has been that there should

be house for all by the year 2000 (Chionuma, 2003). Unfortunately however, very little

has been achieved till now. One of the major reasons for the failure of the program was the

continuous increase in prices of various construction materials and also little or none

availability of alternatives to the expensive materials such as steel. With cost control and

management in mind, local fibres from straws, , ropes, coconut, herm, cotton, palm

tree, etc are being used as strengtheners to alleviate the problems of cost and availability

of materials (Cement and Concrete Institute 2000).

Berg (1996) declared that fibers are readily available everywhere, and that there are the

natural fibers which came from animals (e.g. wool, hair and silk) or from plant (e.g. cotton,

flax, hemp and reeds). Berg explained that there are plastic or synthetic fibers which are Full text of this document can be accessed by visiting the Post Graduate Research Unit of Albert Ilemobade Library, FUTA or contact the Reference Librarian via [email protected]