Evaluating mechanical properties of fly ash bottom ash (FABA) geopolymer hybrid concrete in peat environment

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Olivia M.
Anwary A.
Wibisono G.
Sitompul I.R.
Supit S.W.M.
Usman F.
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American Institute of Physics Inc.
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Fly ash bottom ash (FABA) with a ratio of 80% fly ash and 20% bottom ash can be included in concrete as an additive or replacement material. The FABA concrete needs to have good mechanical properties in aggressive environments such as acidic peatland to widen its application. In this study, a mix of FABA, alkaline activator and Portland cement produced the FABA hybrid geopolymer concrete. Portland Composite Cement (PCC) was a control mixture. The concrete was mixed, cast and cured for 28 days before placed in peat water until 91 days. This study determines the compressive strength, tensile strength, flexural strength and shrinkage values of the immersed samples. Results show that the FABA-GP hybrid concrete has a stable compressive strength development after 28 days. However, the tensile strength of the FABA-GP dropped by 12.9% at 91 days, indicating a slow degradation in concrete. The flexural strength of FABA-GP was not affected due to a slight decrease at 91 days in peat water. The FABA-GP has a relatively higher shrinkage than the PCC concrete. Moreover, the mechanical properties of FABA-GP hybrid concrete suggest the material could be used as low to medium grade concrete in peatland. � 2021 Author(s).