Effect of Freezing-Thawing Cycles on the Physical and Mechanical Characteristics of Concrete (original) (raw)
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Stress Analysis for Concrete Materials under Multiple Freeze-Thaw Cycles
Journal of Advanced Concrete Technology, 2015
Once ice forms in highly saturated concrete material, internal tensile stress will be generated and causes damage to the material, which is a serious problem for concrete structures in cold and wet regions. On one hand, each component (porous body, ice and liquid) should satisfy the compatibility of stress and strain, which has been discussed by the poromechanical theories. On the other hand, if some empty voids exist, the hydraulic pressure will release when liquid water escapes from the expanded area according to Darcy's law. Recent closed freeze-thaw tests on the saturated mortar showed a consistent tendency: as the number of freeze-thaw cycles (FTC) increases, the deformation changes from the expansion to the contraction. In order to make clear the physical and mechanical changes during this process, a more comprehensive hydraulic model is developed, which combines both the mechanisms mentioned above. The estimated strain behavior by this model is in a good agreement with experimental measurements, and also, it has good potential and is more flexible to be applied to different cases such as different saturation degrees and cooling rates. The permeability change can be also considered in this model as a reflection of frost damage level.
Freeze-Thaw Resistance of Concrete: Insight from Microstructural Properties
2018
Composite cements offer low carbon alternatives to conventional CEM I. These also generally tend to perform better than CEM I in aggressive chemical environments. However, the freeze-thaw resistance, evident through surface scaling and internal damage is usually impaired. Postulated theories on freeze-thaw induced damage do not fully explain the origin of this weakness in composite cement concretes. This contribution systematically presents the phase assemblage changes associated with the freeze-thaw of concrete specimen made from composite cements with and without limestone. The freeze-thaw test was performed on concrete according to CIF method based on CEN/TR 15177 and the corresponding cement pastes characterized by X-ray powder diffraction (XRD) and thermogravimetric analysis (TGA). In all investigated composite cements, portlandite was already depleted after the 7d capillary suction. The implications of this and other modified assemblages during the conditioning and the freeze-...
Freeze-thaw resistance of concrete with porous aggregate
Procedia Engineering, 2010
This paper deals with the influence of periodic freezing on lightweight concrete characteristics. Sets of lightweight concrete prismatic specimens are cyclically frozen in range from +20°C to-20°C and non-destructively tested after every 25 cycles. Freeze-thaw resistance is determined from measurement of the frost-attacked and non-frost-attacked (referential) specimens. The referential specimens are air/water-cured. Non-destructive methods, especially ultrasonic impulse method and resonance method are used for determination of specimen's degradation. Experiments are finished with destructive test in order to determine the static modulus of elasticity.
Mechanical and durability properties of concrete subjected to early-age freeze-thaw cycles
Materials and structures, 2021
Early-age frost damage to concrete used in winter construction or in cold environments negatively affects the development of the hydration process and the performance of the concrete, thereby reducing the service life of the building structure. Experimental research was carried out to investigate the compressive strength, resistance to chloride penetration and resistance to freeze-thaw of concrete specimens subjected to earlyage freeze-thaw cycles (E-FTCs). The effects that different pre-curing times of concrete and mineral admixtures have on the properties of early-age frostaffected concrete were also analyzed. Results show that the earlier the freeze-thaw cycles (FTCs), the poorer the later-age performance. Later-age water-curing cannot
Freeze-Thaw Resistance of Concrete: Effect of: Curing Conditions, Moisture Exchange and Materials
2001
Research on freeze-thaw resistance of concrete in general and on curing and moisture conditions in particular is motivated from an economic and product sustainability point of view. Specifically, it is argued for the importance of considering the effect of curing and test exposure conditions on the moisture uptake and performance during freeze-thaw. Due to the demonstrated importance of moisture conditions on performance, they should be related to those of field service conditions when choosing a test procedure in a particular case. This is vital for adequate testing of newand more sustainable concrete materials.
Effect of freezing-thawing on concrete behavior
Challenge Journal of Concrete Research Letters, 2018
This study aims to determine the effect of change of temperature (freezing-thawing cycles) on the behavior of the mortar and the concrete. Also, the evaluation of the effect of air entering for improving the durability of the mortar and concrete was discussed. 23 mixes were cast to evaluate the purpose of this study. Cement types (Portland cement and limestone cement), aggregate types (dolomite and gravel), dosages of air entering 0.01, 0.1, 0.15 and 0.2% of cement weight and freezing thawing cycles (50, 100, 150, 200, 300 and 400 cycles) were considered. Relative dynamic modules of elasticity which is illustrated the internal cracks growth, durability factor and losses of weight were evaluated. Empirical correlations were formulated. The results showed that; 0.15% air entrained of cement weight improve the durability in term of freezing-thawing; where the durability factor for the mixes was ≥ 85% that exposed to freezing-thawing cycles in range 0-200. Up to 200 cycles of freezing-t...
The Damage Mechanism and Strain Induced in Frost Cycles of Concrete
The damage of concrete under frost cycles was associated with the hydraulic pressure in the pore space system and the internal shrinkage due to water redistribution during sub-zero temperature. Some experimental works on different size of concrete specimens were conducted to study the strain induced in concrete under frost cycles effect. Finally, the damage mechanism on frost cycles of concrete is proposed.
MATEC Web of Conferences, 2020
The paper deals with a pilot study focused on the freeze-thaw (F-T) resistance of concrete. A non-traditional approach to the evaluation of the F-T resistance of concrete based on the determination of the fracture parameters is presented in the paper. Three types of specimens were used in the experimental program – prisms with edge and Chevron notch, and cylinders with the Chevron notch. Three sets of specimens of each shape were tested in total. The reference set was stored in the water until the time of testing. Another two sets of specimens were subjected to 50 and 100 freeze-thaw tests, respectively. One F-T cycle consisted of 4 hours freezing in the air at temperature -18 °C and 2 hours thawing in the water at temperature +20 °C. Based on the results, it can be stated that the values of fracture energy are proportional to the area of the ligament. This finding was observed for all tested sets – non-frost and frost attacked. The values of modulus of elasticity and fracture tough...
The Assessment of Prediction Methodology of Concrete Freezing and Thawing Resistance
Materials Science, 2012
Investigation was performed in order to determine whether the predicted frost resistance of concrete in cycles, while using porosity parameters, corresponds to the number of cycles determined experimentally. The porosity parameters of concrete were determined by measuring kinetics of water absorption. The number of concrete freezing and thawing cycles was predicted by a method proposed by Sheikin, according to porosity parameters of concrete. Frost resistance of concrete was determined by using volumetric method of freezing. It was found, that depending on kinetics of water absorption and composition of concrete, closed porosity of concrete varies within the limits from 3.51 % to 10.62 %, open porosity of concrete varies within the limits from 10.96 % to 15.09 %, and predicted number of frost resistance of concrete in cycles varies within the limits from 550 to 1000. After volumetric freezing of concrete samples, according to predicted number freezing and thawing cycles, it can be stated, that concrete with fine aggregate did pass predicted number of cycles, but concrete with coarse aggregate did not. In this case, predicted criterion K F of concrete of freezing and thawing resistance proposed by Sheikin, should be corrected by supplementing it with additional coefficient. The coefficient could be related to the concentration of fine aggregate from the total amount of aggregate.