The Effect of Microbes and Fly Ash to Improve Concrete Performance

This paper presents the application of�fly ash�combining with microbes in concrete to reduce cement content.�A class F fly ash as cement replacementwas applied with ratios of 20%, 30%, 40%, and 50% to reduce hydration heat. Microbes from bacterial consortium were applied to as the filler to increase concrete compressive strength. The concrete mix design from SNI 03�2834�2000 was applied for a compressive strength target of 30 MPa. The mechanical test was carried out consisting compressive and tensile test.�Concrete�workability�and the heat hydration measurement were performed for fresh concrete.�The results showed that the maximum strength of 45.10 MPa was obtained from specimens with 30% fly ash content.�Application of microbes associated with�fly ash content of 40% showed the maximum strength of 48.47 MPa.�It was found that the tensile strength also increased with the application of�fly ash�and microbes.�Hydration temperature of concrete decreased with the increase of�the ash�content.�This proves that the application of�fly ash�and microbes in concrete can reduce the cement as well as increasing the concrete performance.