Experimental Analysis of Fly Ash Based Geopolymer Concrete Using Recycled Materials Replacement For Use As Column Materials In Ground Improvement

Abstract

The reuse of waste materials can help to solve problems relating to placing them in landfills and can be a step towards environmental sustainability by decreasing the production demand of cement for concrete. The use of Geopolymer concrete is one of the possible solutions that is rapidly gaining popularity among researchers In this study, an attempt has been made to produce fly ash based geopolymer concrete using recycled waste materials replacement such as slag and quarry rock dust for construction. Four geopolymer concrete composites including normal concrete mixture, fly ash based geopolymer concrete containing 5% cement, fly ash and slag (1:1) based geopolymer concrete and fly ash, slag, and rock quarry dust (1:0.9:0.1) based geopolymer concrete were produced. Sodium hydroxide with molarity of 14 and sodium silicate solutions were used as an alkaline activator in this research. The mechanical properties of the concrete composites were evaluated by conducting compressive strength test, tensile strength test and flexural strength test. It was found out that 50% fly ash, 45% slag & 5% quarry rock dust based geopolymer concrete cured at higher temperatures of 65 C showed an increase of 8% compressive strength at 28 days when compared with that of control mix of 28 days, whereas FGPC with 5% cement admixture showed an increase of 16% in 28 days compressive strength form the control mix. Similarly, the 28 days flexural strength of 50% fly ash, 45% slag & 5% quarry rock dust based geopolymer concrete was slightly higher than FGPC with 5 % cement as an admixture and 4 % down in flexural strength with that of control mix at 28 days. Cost analysis for all sample, which indicates that the sample composed of 5% Cement + GPC has the lowest cost among all the batches and almost 25% less than OPCC. Although all batches have the same size. Moreover, the 5% QRD + 45% Slag & 50% FA cost is 15 - 18% less than OPCC. After comparing all batches having different composition, it becomes evident that the 50% FA + 50% Slag is 10% cheaper than OPCC.

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