A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the Mechanical Engineering Programme Area of University Teknologi Brunei Abstract The fibers that have been extracted from bamboo and sugarcane plants were mixed with Portland cement and water to produce fiber-reinforced cement composite cylinders. A pure cement cylinder without the inclusion of any fiber was prepared as a control sample. To investigate the effect of the treatment of the fibers, some of the fibers are mechanically treated and some are left untreated. Bamboo reinforced cement composite cylinders are then produced with different loading by weight of both treated and untreated fibers. The scope of this project includes lab experiments on samples of bamboo and sugarcane fiber-reinforced cement composites placed on a hot plate. The variation of temperature at different points of the samples are recorded until steady-state was achieved. The temperature difference from the readings was then used to calculate the thermal conductivity of the composites. This investigation allowed the correlation between the thermal conductivity and the fiber loading of the cement composite to be made. The effect of treatment of fibers on the thermal conductivity of the cement composite was also studied. Increasing the load has a negative effect on the thermal conductivity of the treated and untreated fiber composite, whereas the mechanical treatment of the fiber enhanced the thermal conductivity value of the sugarcane fiber cement composite. Although the same effect of fiber loading was observed for the as-received bamboo fiber composite, the fiber loading effect has the opposite effect towards the treated fiber composites where the thermal conductivity increases as the fiber loading increases. Furthermore, instead of enhancing the thermal conductivity of the composite, the treatment has the contradictory effect of lowering the composites' thermal conductivity in comparison to the as-received.