most of the codes and service life literature provide model for chloride based degradation however i couldn't find any model for sulphate based degradation especially sulphuric acid degradation in sewage system. only reliable equation and formulae is given by pomeroy in 1974. any latest development in this field.
Most of the available equations proposed for forecasting S2- build-up in pipes are empirical. see the attached image regarding the generation H2S in pipe. for further information you may check:
Elmaleh, S., et al. "Forecasting of H2S build-up in a reclaimed waste water pipe." Water science and technology 38.10 (1998): 241-248.
regarding the appropriate concrete mix design for the sulfate environment, you may read the attached file.
Hello Ankur Bansal
There is still a lack of studies to improve and make
industrial plants and sewage systems more durable and consistent with the importance.
You might be interested in this work on concrete in cold storage.
Hugs
http://www.set.eesc.usp.br/static/media/producao/2008DO_SandraMariadeLima.pdf
Dear Ankur Bansal,
I agree with Marcos de Oliveira Valin Jr. There is very less number studies available on modelling on sulphate attack on concrete.The reactions which are taking place inside the concrete has been studied as a life models such as phenomenological isotropic damage model, which describes the material degradation. The reactive-diffusion model and the mechanical model have been implemented in a finite element code and used to simulate the experimental tests concerning ESA were studied.
I have attached an article, which will give you glimpse on modelling.
http://www.gruppofrattura.it/pdf/rivista/numero29/numero_29_art_19.pdf
Dear Ankur Bansal, Very true, and in any case it seems difficult to generalise. In contrast to Cl diffusion (sea spray on bridges etc), perhaps being chiefly governed by diffusion constants and local climate, the sewage environment is more complex. I would think it should be possible to model its development. However, that would require an empirical basis and sound input data regarding the effects of bacterial activity (variable), the degree of airing in the actual sewage (acid potential increases if H2S accumulation increases); the concrete material properties (w/b, and mix-design), overall design as well as degree of turbulent flow etc etc. If you look up my ResearchGate site you will find yet another recent case study (Fernandes et al from a Portuguese site), which I hope will assist you in Your further work on this important matter.
Dear Ankur Bansal,
There is a PhD thesis from Aalborg University by Dr Henriette Jensen, "Hydrogen sulfide induced concrete corrosion of sewer networks" which you can find here: http://vbn.aau.dk/files/19097739/Henriette_Stokbro-Ph.d.pdf
Dr Henriette Jensen now works at the Univesrity of Sheffield: https://www.sheffield.ac.uk/cbe/staff/staffprofiles/hjensen
In the abstract of here thesis you can read:
The oxidation kinetics of hydrogen sulfide was combined with the existing WATS (Wastewater Aerobic-anaerobic Transformations in Sewers) model concept. This model concept is applied to simulate processes taking place in wastewater during transport in sewer networks. The combined model was applied to predict corrosion rates in a simple gravity sewer pipe downstream of a force main. The results of the model emphasized the active hydrogen sulfide oxidizing biomass as a key parameter in the prediction of corrosion rates. Furthermore it was found, that slowly biodegradable elemental sulfur comprised up to 70% of the entire sulfur pool in the corrosion products. This means that an assumption that all hydrogen sulfide supplied to the concrete surfaces contributes to the corrosion may lead to overestimation of the corrosion rate.
Dear Ankur Bansal,
Perhaps, the attached paper can partially contribute to this discussion:
M. Šomodíková, B. Teplý, D. Vořechovská & D. Lehký (2015) Modelling of the service life of concrete structures under combined mechanical and environmental actions. ESREL -
Safety and Reliability of Complex Engineered Systems – Podofillini et al. (Eds)
© 2015 Taylor & Francis Group, London
- Badges
- Science topic