“…In addition to traditional types of concrete, reactive powder concrete has become a new generation of concrete with great potential for application owing to its ultra-high-strength, remarkable durability and high toughness (Abid et al, 2017). Abid et al (2019) studied the creep behavior of reactive powder concrete to determine its free thermal strain, short-term creep and transient strain at high temperature.…”
Section: Ec 397 2532mentioning
confidence: 99%
“…To validate the effect of the variable-order fractional creep model, the experimental data of two representative concrete are utilized. The creep behavior of reactive powder concrete at high temperature is studied by Abid et al. (2019).…”
Section: Comparison To Experimental Datamentioning
confidence: 99%
“…To validate the effect of the variable-order fractional creep model, the experimental data of two representative concrete are utilized. The creep behavior of reactive powder concrete at high temperature is studied by Abid et al (2019). The applied stress levels (σ=f T c ) are 0.2, 0.4 and 0.6 of compressive strength at the target temperatures and are kept for three hours.…”
Section: Comparison To Experimental Datamentioning
confidence: 99%
“…, 2017). Abid et al. (2019) studied the creep behavior of reactive powder concrete to determine its free thermal strain, short-term creep and transient strain at high temperature.…”
PurposeCreep behavior of concrete at high temperature has become a major concern in building structures, such as factories, bridges, tunnels, airports and nuclear buildings. Therefore, a simple and accurate prediction model for the high-temperature creep behavior of concrete is crucial in engineering applications.Design/methodology/approachIn this paper, the variable-order fractional operator is introduced to capture the high-temperature creep behavior of concrete. By assuming that the variable-order function is a linear function with time, the proposed model benefits from the advantages of both formal simplicity and the physical significance for macroscopic intermediate materials. The effectiveness of the model is demonstrated by data fitting with existing experimental results of high-temperature creep of two representative concretes.FindingsThe results show that the proposed model fits well with the experimental data, and the value of order is increasing with the increase of the applied stress levels, which meets the fact that higher stress can accelerate the rate of creep. Furthermore, the relationship between the model parameters and loading conditions is deeply analyzed. It is found that the material coefficients are constant at a constant temperature, while the order function parameters are determined by the applied stress levels. Finally, the variable-order fractional model can be further written into a general equation of time and applied stress.Originality/valueThis paper provides a simple and practical variable-order fractional model for predicting the creep behavior of concrete at high temperature.
“…In addition to traditional types of concrete, reactive powder concrete has become a new generation of concrete with great potential for application owing to its ultra-high-strength, remarkable durability and high toughness (Abid et al, 2017). Abid et al (2019) studied the creep behavior of reactive powder concrete to determine its free thermal strain, short-term creep and transient strain at high temperature.…”
Section: Ec 397 2532mentioning
confidence: 99%
“…To validate the effect of the variable-order fractional creep model, the experimental data of two representative concrete are utilized. The creep behavior of reactive powder concrete at high temperature is studied by Abid et al. (2019).…”
Section: Comparison To Experimental Datamentioning
confidence: 99%
“…To validate the effect of the variable-order fractional creep model, the experimental data of two representative concrete are utilized. The creep behavior of reactive powder concrete at high temperature is studied by Abid et al (2019). The applied stress levels (σ=f T c ) are 0.2, 0.4 and 0.6 of compressive strength at the target temperatures and are kept for three hours.…”
Section: Comparison To Experimental Datamentioning
confidence: 99%
“…, 2017). Abid et al. (2019) studied the creep behavior of reactive powder concrete to determine its free thermal strain, short-term creep and transient strain at high temperature.…”
PurposeCreep behavior of concrete at high temperature has become a major concern in building structures, such as factories, bridges, tunnels, airports and nuclear buildings. Therefore, a simple and accurate prediction model for the high-temperature creep behavior of concrete is crucial in engineering applications.Design/methodology/approachIn this paper, the variable-order fractional operator is introduced to capture the high-temperature creep behavior of concrete. By assuming that the variable-order function is a linear function with time, the proposed model benefits from the advantages of both formal simplicity and the physical significance for macroscopic intermediate materials. The effectiveness of the model is demonstrated by data fitting with existing experimental results of high-temperature creep of two representative concretes.FindingsThe results show that the proposed model fits well with the experimental data, and the value of order is increasing with the increase of the applied stress levels, which meets the fact that higher stress can accelerate the rate of creep. Furthermore, the relationship between the model parameters and loading conditions is deeply analyzed. It is found that the material coefficients are constant at a constant temperature, while the order function parameters are determined by the applied stress levels. Finally, the variable-order fractional model can be further written into a general equation of time and applied stress.Originality/valueThis paper provides a simple and practical variable-order fractional model for predicting the creep behavior of concrete at high temperature.
“…Furthermore, these structures may catch fire and temperature will increase to the accidental condition. Furthermore, the short-term creep for 3 h of fire exposure is up to 32 times greater than that of one-year ambient temperature creep [ 18 ]. Therefore, the creep behaviour of concrete at high temperatures is critical for designing fireproof structures.…”
Glazed hollow bead insulation concrete (GHBC) presents a promising application prospect in terms of its light weight and superior fire resistance. However, only a few studies have focused on the creep behaviour of GHBC exposed to high temperatures. Therefore, in this study, the mechanism of high temperature on GHBC is analysed through a series of tests on uniaxial compression and multistage creep of GHBC, exposed from room temperature up to 800 °C. The results show a decrease in the weight and compressive strength of GHBC as the temperature rises. After 800 °C, the loss of weight and strength reach to 9.67% and 69.84%, respectively. The creep strain and creep rate increase, with a higher target temperature and higher stress level, while the transient deformation modulus, the creep failure threshold stress, and creep duration are reduced significantly. Furthermore, the creep of GHBC exhibits a considerable increase above 600 °C and the creep under the same loading ratio at 600 °C increases by 74.19% compared to the creep at room temperature. Indeed, the higher the temperature, the more sensitive the stress is to the creep. Based on our findings, the Burgers model agrees well with the creep test data at the primary creep and steady-state creep stages, providing a useful reference for the fire resistance design calculation of the GHBC structures.
In this investigation, a phase change material with a melting temperature of about 450 C (PCM-45) is prepared and applied to solve microstructure degradation problem of concrete matrix when exposed to temperatures more than 500 C. The morphology changes of PCM-45 and the improvement effects of PCM-45 on microstructure of cement matrix are investigated based on microstructure characteristics, ultrasonic pulse velocity of cement paste and compressive strengths of cement mortar with different dosages of PCM-45 at 500, 600, 700, 800 and 900 C. The results show that morphology of PCM-45 is changed, indicating that PCM-45 transforms from solid to liquid phase and that the liquefied PCM-45 can diffuse at elevated temperatures. When temperature returns to room temperature, the liquefied PCM-45 becomes solidified, during which process the microstructure of cement matrix is improved. Therefore, compressive strength and ultrasonic pulse velocity of specimens with PCM-45 are greatly increased compared to those of specimens without PCM-45.
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