The goal of this research was to develop an experimental method for evaluating the physical and chemical CO2 sorption capacity of solid waste from the coal energy and cement industries with a new material called ash carbonated concrete (ACC). The proposed ACC material is a highly porous cementitious material intended to rapidly sequester CO2 and reduce other coal energy waste. ACC relies on the bonding of ash with cement to physically stabilize ash material, and calcium carbonation to chemically fixate CO2. To accurately quantify the CO2 absorption process, a new testing technique was proposed. The constant temperature pressurized reaction chamber (CTPRC) isolates temperature effects and measures gas absorption volumes through pressure change measurements. Results from different blends of ash, aluminum, water, and cement indicate that the CTPRC can accurately differentiate chemical and physical sorption and quantify the amount of consumed CO2.