The influence of hydrothermal carbonization and chemical treatment on concrete properties

The process of hydrothermal carbonization, also known as HTC, is a thermochemical pretreatment method involving the utilization of heated, pressurized water to treat biomass and produce hydrochar. This research investigates the feasibility of using hydrochar produced from coconut fiber in concrete. It also evaluates the effect of HTC duration and the chemical treatment of coconut fiber on the qualities of concrete. Throughout the hydrothermal carbonization process, which usually lasts for 2, 3, and 4 hours, the temperature of 160 °C is kept constant. In this research, we utilized two types of coconut fiber: untreated coconut fiber and pretreated coconut fiber. The characteristics of the concrete, including its slump, dry density, compressive strength, and splitting tensile strength, were analyzed. The diameter of the sample is 10 cm, and it is 20 cm from top to bottom. The length of the HTC duration and the chemical treatment of the fibers have an influence on compressive strength, slump, and splitting tensile strength. On the other hand, they do not have an effect on the dry density. The highest slump was obtained at 4 hours of HTC processing for both types of fibers. The optimum compressive strength in concrete using untreated hydrochar is 28,43 MPa, but the greatest compressive strength using pretreated hydrochar is 25.16 MPa. Untreated hydrochar has the greatest compressive strength at 4 hours of HTC processing, while pretreated hydrochar has it at 2 hours of the HTC processing. In contrast, untreated hydrochar has the highest spliting tensile strength at 2 hours of the HTC processing, while pretreated hydrochar has it at 4 hours of the HTC processing.