The Nature of Coconut Fibre Fly Ash-Based Mechanical Geopolymer

Abstract

In order to reduce carbon emissions in the atmosphere, one of the steps is to use environmentally friendly concrete. Environmentally friendly concrete uses industrial waste as a substitute for cement, such as rice husk ash, palm burning ash, coal burning ash or fly ash. Today, the development of the use of fly ash as a substitute for cement has been widely used, especially in geopolymer concrete. This study uses natural fibres such as coconut fibre. Coconut fibre is also an alternative material in the use of natural fibres as geopolymer mortar composites. This research carried out compressive strength and flexural strength test by doing several variations such as the length of coconut fibres 10 mm, 20 mm, and 30 mm and the percentage of fibre used was 0, 0.25% and 0.50% of the weight of the mortar. Geopolymer mortar made from 100% fly ash. The concentration of NaOH solution used was 14 M and 16 M. The results of this study indicate that the fibre length of 30 mm with a percentage of 0.50% fibre at a concentration of 16 M NaOH solution gives a compressive strength of 40.016 MPa and the greatest flexural strength of 8.799 MPa at 28 days mortar age.