Investigation on the Properties of Fly-Ash Based Hybrid Geopolymer Concrete with Bottom-Ash Municipal Solid Waste Incineration as A Partial Replacement of Fine Aggregates

Abstract

Geopolymer concrete is an innovative construction material which shall be produced by the chemical action of inorganic molecules. The most important purpose of this research is concerning about the resource optimization in the production of concrete. Each year, vast amounts of natural resources are consumed to manufacture ordinary Portland cement which itself causes considerable environmental problems. Geopolymer can be considered as the key factor which does not utilize Portland cement, nor releases greenhouse gases. Sufficient data is available about researches on fly ash based geopolymer concrete, but cement hybrid geopolymer concrete using both fly ash and bottom ash has a new era. Fly Ash, a by- product of waste obtained from the burning of municipal solid waste is plenty available worldwide. Bottom ash is another waste from the burning of municipal solid waste and was used as partial replacement of sand in fly ash based geopolymer concrete and the ideal percentage of this replacement was one of the aims of this project. This paper briefly reviews the constituents of geopolymer concrete, its strength and potentialapplications. To achieve this objective systematic literature review and laboratory investigation was conducted. To find 7 and 28 days compressive strength, three100??100??100mm specimens with 0, 20, 40 and 60 percent replacement of bottom ash were prepared and cured at ambient condition (280C). Same condition of curing was provided and 100??100??500mm prisms were tested to find flexural strength at 7-day and 28-day of the four mixtures. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solution 14M with ratio of 2.5 were used as alkaline activator and all other parameters were kept constant to ignore other unknown influences. The optimum rate of cement and bottom ash replacement was 50% and 20% respectively which produced geopolymer concrete with 28-day compressive strength of 26.5MPa, tensile strength of 2.81MPa and flexural strength of 4.30MPa. finally, the study develop a framework that will assist the use of geopolymer concrete in different area of construction. The outcome of the research willprovide practical inputs to expand knowledge in this area and will encourage researchersto conduct further studies and highlight the use of geopolymer concrete in construction sector of Ethiopia and other developing countries.