Full Title: Geopolymer Cements: Resistance-Engineered Sewer Infrastructure for Longevity using Innovative, Energy-efficient, Synthesis Techniques (RESILIENT)
Participants: Mohammad Matar, Xu Chen, JP Gevaudan
Primary Investigator: Wil Srubar III (CU Boulder)
Co-Investigator: Claire White (Princeton University)
Summary: The primary objective of this Extremely Durable Cementitious Materials project is to engineer an ultra-acid-resistant low-calcium alkali-activated (geopolymer) cement paste specifically for wastewater (i.e., sewer) infrastructure applications to address the critical need for concrete materials with enhanced biogenic sulfuric acid resistance compared to ordinary portland cement (OPC) concrete.
In the United States, local governments spend approximately $50 billion annually on the construction, operation, and maintenance of over 800,000 miles (1,300,000 km) of concrete sewers – $13.8 billion of which is specifically used to prevent and mitigate the effects of microbial-induced concrete corrosion (MICC). While sulfuric acid destabilizes and dissolves the calcium-rich phases in OPC, yielding weak, gypsiferous reaction products and deterioration severe enough to cause collapse, low-calcium geopolymers laden with polyvalent cations (i.e., Mg(OH)2, Fe(OH)3, and, in some cases, Ca(OH)2) have been shown by the PI, Co-PI, and others to exhibit exceptional acid resistance to sulfuric acid compared to OPC.
The resulting geopolymer cement paste formulations will exhibit 80% reductions in steady-state biodeterioration rates compared to OPC concrete (from ~5 mm/year (0.20 in.year) to ~1 mm/year (0.04 in/year)), which will extend the service life of concrete sewer infrastructure ~5X and will yield reductions in total life cycle environmental (i.e., embodied energy and embodied carbon) costs of mitigating biogenic sulfuric acid degradation by ~75%.