LowEmissionAsphalt-136pg-WhitePaper-May2023

P a g e | 130 Portland Cement Concrete – Natural Carbon Sink PCC surface courses represent less the ten percent of U.S. pavements, but many are prime targets for photocatalytic upgrade as they tend to dominate high traffic and emissions volume intensive applications such as bridges, tunnels, airports, and parking structures.TiO 2 cannot be successfully incorporated or manufactured into fresh asphalt binder due to mineral coating or “hiding” during heated assembly and lack of mineral load near the surface, 285 but can be blended successfully into new concrete. 286 The issue is cost of the upgrade favoring a retrofit approach such as PlusTi TM which is less than 5% (1/20) of the cost of a new, full depth TiO 2 enhanced PCC pavement (Table 23) . Table 23 – Cost of Full-Depth Photocatalytic Concrete vs. TiO 2 Topical Treatment Est. Cost Per yd 2 RS Means 10” PCC $43 RS Means 10” PCC w/ TiO2 $64 Photocatalytic Penetrant 287 $2 - $3 Source: Louisiana State University (LSU), Department of Construction Management; Pavement Technology, Inc. PCC also is a natural carbon sink capable of recapturing as much as 25% of its embodied carbon over its lifecycle. 288 289 Good news! This is related to concrete cement containing calcium , so it’s identical to other geological carbon mineralization strategies such as basalt fields and other enhanced 285 Hassan M, Mohammad L, et al, A Breakthrough in the Preparation of Highly-Sustainable Photocatalytic Warm Asphalt Mixtures , Louisiana State University (LSU), National Science Foundation (NSF) Engineering Research and Innovation Conference, Atlanta, Georgia 2011. 286 HeidelbergCement Group, Photocatalytic Communication Kit: The role of photocatalytic cement-based products as sustainable solutions , www.heidelbergcement.com/en/sustainable-products . 287 PlusTi TM - TiIntroCME All Purpose Pollution Remediation Penetrant. 288 Velay-Lizancos et al, Modification of CO 2 capture and pore structure of hardened cement paste made with nano- TiO 2 addition: Influence of water-to-cement ratio and CO 2 exposure age, Purdue University 2021. 289 Major construction firms team up to get carbon out of concrete , Canary Media, July 2022. Adding photoreactive TiO 2 doubles the lifespan carbon uptake efficiency in concrete to 50%. .