Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in s...Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in service is a recurring problem due to the immediate or overtime appearance of cracks. The objective of this work was therefore to assess the damage phenomena of the steel-concrete interface in order to assess the performance of an RC structure. Samples of approximately 30 cm of reinforcement attacked by rust were taken from broken reinforced concrete columns and beams in order to determine the impact of corrosion on high adhesion steel (HA) and therefore on its ability to resist. The experimental results have shown that the corrosion degradation rates of reinforcing bars of different diameters increase as the diameter of the reinforcing bars decreases: 5% for HA12;23.75% for HA8 and 50% for HA6. Using the approach proposed by Mangat and Elgalf on the bearing capacity as a function of the progress of the corrosion phenomenon, these rates made it possible to assess the new fracture limits of corroded HA steels. For HA6 respectively HA8 and HA12, their initial limit resistances will decrease by 4/4, 3/4 and 1/4. Based on the results of this study and in order to guarantee their durability, an RC structure can be dimensioned by taking into account the effects of reinforcement corrosion.展开更多
The effect of multiple-step thermal ageing treatment (MSTAT) on the corrosion characteristics of A356.0-type Al-Si-Mg alloy in simulated seawater has been studied. The MSTAT treatment also consists of Double Thermal A...The effect of multiple-step thermal ageing treatment (MSTAT) on the corrosion characteristics of A356.0-type Al-Si-Mg alloy in simulated seawater has been studied. The MSTAT treatment also consists of Double Thermal Ageing (DTAT- T7), Single Thermal Ageing (STAT- T6), Step- Quenching and Ageing (SQA). The corrosion of the thermal treated samples was characterized by electrochemical Potentiodynamics polarization techniques consisting of linear polarization and chronopotentiometric method using the fit Tafel plot. Generally, from the linear polarization, the corrosion rate decreases at all temperatures with the ageing time. The corrosion behavior of the DTAT and SQA Al-Si-Mg alloy in the simulated seawater showed better resistance than the STAT Al-Si-Mg alloy. Samples in the SQA-STAT have improved corrosion resistance than the SQA-DTAT one. The chronopotentiometric corrosion study of some selected samples indicates a decrease in the corrosion resistance with open circuit potential exposure time. Consequently, the form of corrosion in the studied Al-Si-Mg alloy are slightly uniform and predominantly pitting corrosion as obtained from the SEM study. The pits diameter were found to range from 30-50μm.展开更多
文摘Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in service is a recurring problem due to the immediate or overtime appearance of cracks. The objective of this work was therefore to assess the damage phenomena of the steel-concrete interface in order to assess the performance of an RC structure. Samples of approximately 30 cm of reinforcement attacked by rust were taken from broken reinforced concrete columns and beams in order to determine the impact of corrosion on high adhesion steel (HA) and therefore on its ability to resist. The experimental results have shown that the corrosion degradation rates of reinforcing bars of different diameters increase as the diameter of the reinforcing bars decreases: 5% for HA12;23.75% for HA8 and 50% for HA6. Using the approach proposed by Mangat and Elgalf on the bearing capacity as a function of the progress of the corrosion phenomenon, these rates made it possible to assess the new fracture limits of corroded HA steels. For HA6 respectively HA8 and HA12, their initial limit resistances will decrease by 4/4, 3/4 and 1/4. Based on the results of this study and in order to guarantee their durability, an RC structure can be dimensioned by taking into account the effects of reinforcement corrosion.
文摘The effect of multiple-step thermal ageing treatment (MSTAT) on the corrosion characteristics of A356.0-type Al-Si-Mg alloy in simulated seawater has been studied. The MSTAT treatment also consists of Double Thermal Ageing (DTAT- T7), Single Thermal Ageing (STAT- T6), Step- Quenching and Ageing (SQA). The corrosion of the thermal treated samples was characterized by electrochemical Potentiodynamics polarization techniques consisting of linear polarization and chronopotentiometric method using the fit Tafel plot. Generally, from the linear polarization, the corrosion rate decreases at all temperatures with the ageing time. The corrosion behavior of the DTAT and SQA Al-Si-Mg alloy in the simulated seawater showed better resistance than the STAT Al-Si-Mg alloy. Samples in the SQA-STAT have improved corrosion resistance than the SQA-DTAT one. The chronopotentiometric corrosion study of some selected samples indicates a decrease in the corrosion resistance with open circuit potential exposure time. Consequently, the form of corrosion in the studied Al-Si-Mg alloy are slightly uniform and predominantly pitting corrosion as obtained from the SEM study. The pits diameter were found to range from 30-50μm.
