BOS slag waste demonstrates excellent physical and mechanical attributes and it is capable of substituting natural aggregates to produce structural materials, road pavements, and more. Unfortunately, the use of BOS slags is precluded because of their expansion behavior due to the presence of significant free lime (CaO). The ZAP-C 3 process carbonates the free lime and calcium silicates allowing for BOS slag to be used as a road building aggregate, in combination with a significant carbon sequestration possibility. In traditional processes aggregate is blended with asphalt, but because of the hydrophilic nature of natural aggregate surfaces it is generally required that a solvent is added to facilitate a uniform blend. Researchers at the Central Science Research Institute (CSRI) and Central Road Research Institute (CSRI) in India and in our laboratories have shown that it is possible to make slag hydrophobic through chemical reaction, after which blending with asphalt becomes possible without additional additives. Importantly, the aggregate produced by the ZAP-C 3 process from BOS slag is shown to be hydrophobic and as such is ideal for road construction. This is unlike other "sequestration" processes that claim to immobilize CO2 permanently in the ocean, as dissolved bicarbonate ions. In these systems they rely on natural precipitation, which in turn relies on both chemical and biological conditions being appropriate . When such conditions are not met, the reversibility of the equilibrium causes CO2 leakage.