Microstructural and engineering properties investigation of sustainable hybrid concrete produced from industrial wastes

The wastes generated from manufacturing industry are increasing at an alarming rate and causing severe threats to our environment's sustainability. However, the strategic utilization of industrial waste in construction industry has the potential to solve the problems of waste disposal, unsystematic landfills and it may also reduce the demand for natural resource like river sand. Therefore, this study proposes the novel and sustainable method of concrete production from industrial wastes like coal bottom ash and marble dust. In the present experimental investigation the fine aggregate used for concrete production is fractionally replaced by coal bottom ash and marble dust at 10%, 20% and 30% separately, in the initial stages. Further, a sustainable hybrid concrete is prepared containing coal bottom ash and marble dust together by replacing fine aggregate in the same percentages having equal proportions. The test results shows that the compressive strength is maximum at 20% replacement of marble dust and bottom ash, with fine aggregate, when done individually; whereas in hybrid concrete when prepared with 30% replacement of fine aggregate attains highest 28 days compressive strength of 43.9 ​MPa which is 16.75% higher than control mix. This improved strength is attributed to strength compounds, observed in microstructural investigation, like Calcium silicate hydrate (C-S-H) and Calcium aluminate-silicate hydrate (C-A-S-H) formed in hybrid specimen, prepared in conjunction with silica fume.