EFEKTIVITAS PENAMBAHAN SERAT POLYPROPYLENE TERHADAP KUAT LENTUR BETON GEOPOLIMER dengan SUPERPLASTICIZER

Abstract

Geopolymer concrete is concrete composed of a mixture of coarse and fine aggregate without Portland cement binder.  Fly ash is used as a substitute, because it contains a lot of silica and alumina. Geopolymer concrete has good strength and durability, but concrete also has disadvantages, namely brittleness, workability and often cracking due to tensile loads. Superplasticizer (SP) is used at 2% of fly ash weight to improve workability. The SP used is Sika viscocrete 1003. The addition of polypropylene fiber is one way to overcome brittle properties and the appearance of fine cracks in concrete. In this paper using Sika fiberforce 48mm polypropylene fiber which has a tensile strength of 465N/mm2(MPa) at a dose of 0%, 0.5%, 1%, 1.5% and 2%. The alkaline activator used is a mixture of NaOH and Na2SiO3 solutions. The molarity of the NaOH solution used is 8M with a ratio of NaOH/Na2SiO3 2: 3. From the test results, it is known that the influence of polypropylene fiber is effective for increasing the bending strength of geopolymer concrete. The bending strength value of geopolymer concrete with the addition of polypropylene fibers increased by 60.19%. The polypropylene fiber content will be maximum at a percentage of 0.5% of the total volume of the mixture.

Keywords: Fiber, Flexural Strength, Fly Ash Geopolymer Concrete, Polypropylene, Superplasticizer