Evaluation of strength characteristics for palm kernel oil - based Polyurethane (PKO-P) as a ground improvement method

Abstract

 

Development on soft ground area cannot be avoided at certain area especially nearby coastal or marine area. At urban areas, most of the land has been fully developed and very limited space available, therefore area nearby marine region has to be explored to cater increasing in population in certain country. It is very crucial to stabilize the soft ground before any construction carried out to ensure the structure would be founded on the stable foundation system. Foundation system commonly established for deep soft ground is a pile foundation. There are certain cases whereby pile foundation system failed after completion of structure and the building has been accommodated or been utilized. It causes large settlement which contributes to the failure of structure such as longitudinal crack, sinkholes, beam fractured and so forth. Rectification works have to be done to restore foundation strength thus to prevent further settlement which can cause collapse or major failure of structure. Rectification works that commonly being done nowadays is underpinning pile whereby new pile being installed in between the existing pile to stabilize the foundation and prevent further settlement. This method rather wearisome to be carried out since it involves major excavation and disturbs the existing structure and the surrounding. Therefore it is proposed to carry out Palm Kernel Oil Based Polyurethane (PKO-P) Pile injection to overcome this problem. PKO-P pile injection is a lightweight material to prevent further settlement and the rectification works can be done very fast. No excavation is required and only a small diameter of hole is drilled on the existing slab foundation before injection of PKO-P Pile. PKO-P is a polyurethane processed from palm kernel oil which is renown of the sustainability and green materials. In this research, Unconfined Compression Test been have conducted on few samples of PKO-P materials with different ratio of polyol and isocynate to determine the compressive strength characteristics for PKO-P materials as such to evaluate the performance of the PKO-P for ground improvement. From the test that has been done, the compressive strength achieves its maximum strength at isocynate to polyol ratio of 1:0.75 with maximum compressive strength of 2.3MPa. PKO-P shows rigid characteristics at this maximum strength which produce strong material, able to resist deformation but brittles beyond the maximum stress. With further increasing amount of polyol, PKO-P shows flexible characteristics whereby it undergoes deformation but they tend not to break beyond the maximum stress. Higher elastic modulus recorded for rigid type PKO-P compare to flexible type PKO-P.