Durability of high-volume fly ash concrete incorporating microbes and bottom ash under accelerated chloride attack

Reinforced concrete structures in marine environments usually have durability issues. Chloride in seawater can initiate corrosion of concrete reinforcement, reducing serviceability and eventually leading to structural failure. The simplest solution is to use high-strength concrete, but it is not environmentally friendly due to the high cement content. This paper presents the utilization of high-volume fly ash (HVFA) cement with microbes and bottom ash (BA) to improve the durability of concrete. Concrete strength was evaluated at 7 and 28 days. X-ray diffraction and scanning electron microscopy tests were performed for characterization. The rapid chloride penetration test and the accelerated corrosion test were used to assess the durability of concrete against chloride attack. Porosity and chloride content tests were conducted to support the analysis. Based on the rapid chloride penetration test, it was found that HVFA and microbes reduce the rate of chloride penetration, while the addition of BA increases the rate of chloride penetration. The accelerated corrosion test results show that HVFA concrete has better durability against chloride attack due to its decreased porosity and increased chloride binding capacity. Microbes in HVFA concrete decrease porosity, increasing chloride resistance. Microbes have no effect on the durability of HVFA concrete with BA.