Vitreous carbon aggregate for lightweight concrete

A method for producing a lightweight carbon aggregate, comprising:

• pulverizing coal into a fine coal powder;
• blending the fine coal powder and at least one additive to form a coal mixture;
• pelletizing the coal mixture using a binder to make coal aggregate comprising fine aggregates and course aggregates;
• foaming the coal aggregate to cause volatilization and entrapment of volatized gases in a melted liquid phase at atmospheric pressure by heating to a temperature between 250° C. and 500° C. under an inert gas;
• and
• pyroprocessing the coal aggregate to a temperature between 750° C. and 1240° C. under an inert gas to form a vitreous lightweight aggregate having an apparent density of less than 85 pounds per cubic foot.