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Problem soils
Published in F.G. Bell, Geological Hazards, 1999
Frost action in a soil, of course, is not restricted to tundra regions. Its occurrence is influenced by the initial temperature of the soil, as well as the air temperature, the intensity and duration of the freeze period, the depth of frost penetration, the depth of the water table, and the type of ground and exposure cover. If frost penetrates down to the capillary fringe in fine-grained soils, especially silts, then, under certain conditions, lenses of ice may be developed. The formation of such ice lenses may, in turn, cause frost heave and frost boil, which may lead to the break-up of roads, the failure of slopes, etc.
Assessment of subgrade frost susceptibility from soil index properties
Published in Jean-François Thimus, Ground Freezing 2000 - Frost Action in Soils, 2020
Damage due to frost action is widespread and is essentially caused by the presence of segregated ice lenses in soils creating either excessive deformations or strength-weakening following melting. The formation of ice lenses requires a frost-susceptible soil, a water supply and sub-freezing temperatures. Eliminating one of these conditions suffices generally to significantly reduce the intensity of frost action. Cold region design engineers devoted considerable effort in developing methods for assessing the frost-susceptibility of soils to help in the identification of potential problems.
Introduction
Published in M. Pigeon, R. Pleau, Durability of Concrete in Cold Climates, 2014
The second type of problem arises when freezing occurs after the setting of concrete, but before it has developed significant strength. In this case, ice lenses are formed in large capillary pores and their growth produces internal disruptive pressures which damage the microstructure of cement paste and cause a permanent loss of strength. Sometimes, the damage is so severe that the concrete structure must be, at least partially, reconstructed.
Investigation of mechanical performance and voids structure of cement-stabilised macadam under freeze-thaw actions
Published in International Journal of Pavement Engineering, 2023
Haiyang Liu, Jinsong Qian, Chen Jin, Xin Qian
As seen in Figure 4, the RM and CS of CSM samples with different cement contents decrease as the number of F-T actions increases. Moreover, the RM and CS decrease more significantly in the first several cycles. After 15 cycles, the variation gradually slows down. Therefore, the F-T damage in CSM dose not accumulate linearly but presents the characteristics from fast to slow. The results are consistent with those of other studies (Wang et al.2017b, Wang et al.2017c). The mechanism of F-T damage can be used to explain these results. During the freezing phase, free water in voids forms ice lenses and their volume expands. The pressure from these ice lenses causes distortion of the matrix of particles. Then in the thawing phase, the distortion can’t fully recover after the melting of ice lenses and results in continuous performance deterioration of CSM (Wang et al. 2017c, González et al.2021, Zou et al.2022). However, it is noticed that the moisture content of CSM samples is relatively low and no other moisture is supplied from the surroundings. Therefore, the variation of RM and CS is smaller during the 15∼20 cycles.
Effect of cement and zeolite on silty sand samples under freeze–thaw cycles
Published in Road Materials and Pavement Design, 2022
Saeid Jamshidvand, Alireza Ardakani, Afshin Kordnaeij
The addition of CM enhances the resistance to F-T cycles. The soil is porous and water can move easily through the pores. An important factor that reduces UCS in unstabilized samples because of various F-T cycles is the presence of water in the soil pores, which causes partial saturation in all micro/macro pores. By applying a low temperature (−20°C) to the samples, the water in the pores is frozen. The formed ice lenses have a larger volume than water at room temperature and cause an internal pressure up to about 900 kPa to the surrounding soil particles (Berg, 1998). UCS values for sand with 0, 10, and 20% silt in the 12th cycle are 91.4, 170.8, and 254.9 kPa, respectively. This indicates that as temperature changes, strength diminishes relatively much under unstabilized conditions (Figure 8a, b, and c). By adding CM for stabilisation, some water enters the hydration reaction. Thus, little free water remains in the pores, resulting in formation of fewer ice lenses. The C–S-H and C-A-H gels fill the pores among the particles as well as cause better particle bonding and increase the sample strength.
Effect of frost heave on long-term roughness deterioration of flexible pavement structures
Published in International Journal of Pavement Engineering, 2019
Olivier Sylvestre, Jean-Pascal Bilodeau, Guy Doré
In cold regions, the behaviour of flexible pavements is significantly influenced by frost action and the related phenomena need to be considered to achieve a performing road structure. Damage mechanisms related to seasonal frost can significantly increase the deterioration rate and lead to costly rehabilitation operations. In areas subjected to seasonal freezing, the climatic factors can contribute up to 75% of flexible pavements degradation (Doré et al.2005). One of the deterioration mechanisms associated to seasonal freeze is frost heaving of soils due to ice lens formation. In the Province of Quebec, surface frost heave of up to 200 mm can be encountered for poorly designed pavements (Doré 1997) due to the volume increase when water freezes and, much more importantly, to ice lens growth within frost sensitive subgrade soils. Ice lens formation occurs when three main conditions are encountered: frost-sensitive soils, access to water source and subfreezing temperatures (Konrad and Roy 2000). However, to this day, the relationship between pavement service life and frost heave magnitude has yet to be clearly established. Indeed, in pavement design, it is difficult to assess the benefits or the consequences of theoretical frost heave on pavement service life when the values calculated at the design stage are lower, equal or greater than the allowable thresholds, such as the ones established by the Ministère des Transports, de la Mobilité Durable et de l’Électrification des Transports (MTMDET) according to the functional classification of roads.