Modelling of corrosion protection as standby system for coated reinforced concrete structures

Abstract

Various protective barriers are used in practice to protect reinforced concrete structures in severely aggressive environments. In this paper, we consider a multi‐component corrosion protection system (CPS), taking into account the performance of protective surface barrier, concrete cover and steel reinforcement, which is modelled as a three‐unit of non‐identical components cold standby system. The system is non‐maintained. This is the case when the system is not easily accessible for repair, repair; is time‐consuming and costly. In this system it is assumed that degradation rates of all components are exponential and different. Under these assumptions, using the Markovian degradation process, some important reliability indices such as the system reliability and mean time to failure are defined. In addition, we present simulation results to substantiate the analytical model and to demonstrate the sensitivity analysis to estimate protection system reliability.

Santrauka

Ivairios apsaugines dangos naudojamos gelžbetoninems konstrukcijoms stipriai agresyvioje aplinkoje apsaugoti. Straipsnyje nagrinejama daugiasluoksnq antikorozinq apsauga, susidedanti iš apsauginio barjero, betoninio apsauginio sluoksnio ir plienines armatūros. Sistema modeliuojama kaip triju nevienodu komponentu šaltai rezervinq sistema. Ši sis‐tema yra neremontuojama. Tai atvejai, kai sistema sunkiai pasiekiama, remontas ilgai trunka arba brangus. Tariama, kad sistemos visu komponentu irimo intensyvumas yra eksponentinis ir skirtingas. Remiantis šiomis prielaidomis, naudojant Markovo suirties (atnaujinimo) teorija, kai kurie svarbūs patikimumo rodikliai, tokie kaip sistemos patikimumas ir viduti‐nis laikas iki suirties, gali būti nustatyti. Skaitinis pavyzdys iliustruoja analitinio modelio taikyma ir jo jautruma vertinant antikorozines apsaugines sistemos patikimuma.

Keywords:

• reinforced concrete
• anti‐corrosion protection
• non‐repairable system
• standby system
• Markovian process
• reliability
• time to failure

Reikšminiai žodžiai::

• antikorozinq apsauga
• neremontuojama sistema
• rezervinq sistema
• Markovo procesas
• patikimumas
• laikas iki suirties