Mechanical Performance Improvement by Carbon Dioxide Curing of Cement Concrete Incorporating Oil Shale Residue

The influence of carbon dioxide (CO2) curing on the compressive strength of oil shale ash (OSA) concrete as partial cement replacement was investigated. 15 cm cubes with a 30% replacement percentage were tested after seven days of conventional curing and carbonation curing at 4 bar CO2 pressure. Research results demonstrate that CO2 curing influences the compressive strength of concrete significantly. There is a linear relationship between CO2 pressure and the duration of curing, as well as the compressive strength of OSA-based concrete. A sample of ordinary Portland cement was used as the control sample. The replacement of 30% cement by OSA increased the 7-day compressive strength from 48.5 to 55.5 MPa for plain cement samples and from 36.5 to 42.3 MPa for ash-based samples. From a technical standpoint, OSA-based concrete carbonation curing is still too immature for widespread application. Nonetheless, it is continuously developing in response to greenhouse gas reduction and paving the path for a more sustainable construction materials business.