Microbial activity and corrosion of calcium aluminate concrete in sewers

Author(s): M. Valix, H. Bustamante and J. Sunarho
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume I
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-209-1 (Volume1)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 109-118
Total Pages: 288
Language : English

Abstract: This study examined the microbial activity and corrosion of calcium aluminate concrete (CAC) in sewers. The concrete consisted of CAC with crushed CAC aggregates installed in gravity sewers with environmental conditions of 1.4-654 ppm H2S, 17-30C and 90-99% RH for up to 2.5 years. The performance of CAC was monitored by retrieving coupons every six months. Microbial activity was assessed from the reduction in surface pH and from the biogenic acid generation on the coupons. The rates of corrosion were measured from the thickness and mass loss, and acid permeation through the coupons with time. The surface pH and the generation of organic acids suggest CAC was colonised by fungi at the early phase of corrosion. The fungi appears tolerant to the toxicity of H2S but was susceptible to inhibitive effects on acid production by high H2S. Rates of corrosion of CAC were best captured from the depth of corrosion, overcoming the inconsistency observed in the use of thickness and mass loss. The depth of corrosion was modelled as a power function of proton concentration and time and fitted using regression analysis. The outcome is a holistic model capturing the important variables in the corrosion of CAC.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00