Large-Diameter Sewer Rehabilitation Using a Spray-Applied Fiber-Reinforced Geopolymer Mortar

To assist utilities in making well-informed maintenance decisions, the EPA has developed an innovative technology demonstration program to evaluate technologies that have the potential to reduce costs and increase the effectiveness of the operation, maintenance, and renewal of aging water distribution and wastewater collection systems. Under this initiative, the performance of a new corrosion-resistant fiber-reinforced geopolymer mortar was evaluated. The fiber-reinforced geopolymer mortar was spray-applied to rehabilitate a preselected 49-m-long, 1,500-mm (160-ft-long, 60-in.) RC pipe (RCP) sewer main in Houston, Texas. Costing approximately $1,300–$2,000 per linear meter ($400–$600 per linear foot), a 84-mm-thick (3.3-in.) layer was sprayed uniformly onto the pipe’s interior, surpassing the minimum design thickness value of 48 mm (1.9 in.). The average 28-day compressive strength results of the coating were measured to be approximately 59 MPa (8,635 psi), which is above the manufacturer-stated claim of 55 MPa (8,000 psi) at 28 days. The postlining inspection via closed-circuit television (CCTV) showed a successful rehabilitation with no signs of infiltration, exposed rebar, cracking, or any significant defects. In addition, the project resulted in a carbon footprint of an estimated 60% less than an equivalent excavation project.