Use of Nanomaterials for Concrete Pipe Protection

Abstract

This paper describes an innovative method for mitigating microbial induced corrosion (MIC) in concrete sewer pipes by driving nano-particles containing an antimicrobial agent into the wall of the steel-reinforced cementitious pipe using electrokinetics, an electrical deposition method. Electrokinetic coating involves the application of a weak electric field between the pipe reinforcement and a properly charged solution of nanoparticles. The electrical potential difference drives the nano-particles in the solution into the hardened concrete paste via its pore structure, simultaneously transporting the antimicrobial agent(s) into the pores. This new method of coating creates a mechanical anchorage between the coating liquid and the host matrix, which has inherent advantage over traditional brush or spray-on coating operations. The paper provides a brief overview of recent advances in spray-on coating and lining methods for protecting concrete pipe used in wastewater conveyance systems. Thereafter, a brief description of electrokinetics is provided. Preliminary results of an experimental testing program involving electro-kinetically coating of 35 mock concrete pipe specimens using cuprous oxide, a heavy metal oxide known the have a toxic effect on sulfate reducing bacteria (SRB), are presented. The preliminary testing program focused on examining the effectiveness of using electrokinetics for the treatment of new pipes, partially deteriorated pipes and pipes that exhibited moderate-to-severe deterioration due to sulfuric acid attack. The design of the experiment and the execution of the electrokinetic coating process are also described. The results suggest that the approach could potentially serves as an effective method for coating of new and partially deteriorated reinforced concrete pipes.