During external sulphate attack, the penetration of sulphates within the material is the rate-lim... more During external sulphate attack, the penetration of sulphates within the material is the rate-limiting step. Thus laboratory tests can last a few years before giving usable results. It is possible to shorten the response time by stimulating the penetration of sulphates. One way to achieve that is to dry the material at 60 °C then to saturate it with a sulphate solution before the test. The impact of this thermal pre-conditioning on the sulphate attack phenomenology still remains unclear. Two external sulphate attack tests have been set on two mortar cylinders each. The monitoring of the degradation process made it possible to investigate the influence of the thermal pre-conditioning. The mechanism of external sulphate attack appeared similar for the two tests. Although the mortar cylinders with thermal pre-conditioning showed stronger degradation earlier according to certain parameters (mass, volume, radius), there was no difference regarding the beginning of the expansion.
Carbonation affects the performance, serviceability and safety of reinforced concrete (RC) struct... more Carbonation affects the performance, serviceability and safety of reinforced concrete (RC) structures when they are placed in environments with important CO2 concentrations. Since the kinetics of carbonation depends on parameters that could be affected by climate change (temperature, atmospheric CO2 pressure and relative humidity), this study aims at quantifying the effect of climate change on the durability of RC structures subjected to carbonation risks. This work couples a carbonation finite element model with a comprehensive reliability approach to consider the uncertainties inherent to the deterioration process. The proposed methodology is applied to the probabilistic assessment of carbonation effects for several cities in France under various climate change scenarios. It was found that climate change and local relative humidity have a significant impact on corrosion initiation risks
Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete, 2013
The study presented in this paper deals with the influence of the water saturation of natural agg... more The study presented in this paper deals with the influence of the water saturation of natural aggregates on shrinkage and cracking sensitivity of concrete at early age. Limestone crushed gravels were specially chosen for this study due to their high porosity. The degree of water saturation of gravels varied, from a given concrete mixture, keeping the total water content constant. Significant variations of the plastic shrinkage and early age autogenous deformations were observed. Due to the kinetics of absorption of gravels, the water content remaining in cement paste was different from the effective water content. This was confirmed by the values of mechanical properties and porosimetry. The evolutions of elastic modulus and tensile strength were experimentally assessed and used to compare the cracking sensitivity of the three studied concretes by evaluating the self generated stresses.
During external sulphate attack, the penetration of sulphates within the material is the rate-lim... more During external sulphate attack, the penetration of sulphates within the material is the rate-limiting step. Thus laboratory tests can last a few years before giving usable results. It is possible to shorten the response time by stimulating the penetration of sulphates. One way to achieve that is to dry the material at 60 °C then to saturate it with a sulphate solution before the test. The impact of this thermal pre-conditioning on the sulphate attack phenomenology still remains unclear. Two external sulphate attack tests have been set on two mortar cylinders each. The monitoring of the degradation process made it possible to investigate the influence of the thermal pre-conditioning. The mechanism of external sulphate attack appeared similar for the two tests. Although the mortar cylinders with thermal pre-conditioning showed stronger degradation earlier according to certain parameters (mass, volume, radius), there was no difference regarding the beginning of the expansion.
Carbonation affects the performance, serviceability and safety of reinforced concrete (RC) struct... more Carbonation affects the performance, serviceability and safety of reinforced concrete (RC) structures when they are placed in environments with important CO2 concentrations. Since the kinetics of carbonation depends on parameters that could be affected by climate change (temperature, atmospheric CO2 pressure and relative humidity), this study aims at quantifying the effect of climate change on the durability of RC structures subjected to carbonation risks. This work couples a carbonation finite element model with a comprehensive reliability approach to consider the uncertainties inherent to the deterioration process. The proposed methodology is applied to the probabilistic assessment of carbonation effects for several cities in France under various climate change scenarios. It was found that climate change and local relative humidity have a significant impact on corrosion initiation risks
Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete, 2013
The study presented in this paper deals with the influence of the water saturation of natural agg... more The study presented in this paper deals with the influence of the water saturation of natural aggregates on shrinkage and cracking sensitivity of concrete at early age. Limestone crushed gravels were specially chosen for this study due to their high porosity. The degree of water saturation of gravels varied, from a given concrete mixture, keeping the total water content constant. Significant variations of the plastic shrinkage and early age autogenous deformations were observed. Due to the kinetics of absorption of gravels, the water content remaining in cement paste was different from the effective water content. This was confirmed by the values of mechanical properties and porosimetry. The evolutions of elastic modulus and tensile strength were experimentally assessed and used to compare the cracking sensitivity of the three studied concretes by evaluating the self generated stresses.
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