Specimen (FS) particle images following those freeze-thaw cycles ( zero freeze-thaw cycles (b) 5 freeze-thaw cycle; 10 freeze-thaw cycles 50 freeze-thaw cycles, e 100 freeze-thaw cycles). As illustrated by the concept diagram in Fig. 7. Analyses and discussions. Conceptual diagram showing the variation in the roundness of particles caused by freeze-thaw cycles.1 The shape and texture of particles is tightly linked to the geological setting. In the analysis above we can conclude that the freeze-thaw cycle could modify the particle’s roundness as well as repeated freeze-thaw cycles could cause an increment or decrease in the particle roundness.
According to an introduction in the book the shape and appearance of these particles can provide important information regarding their origin of deposition and transport history 5,6,7 and 8,9,10,11 .1 To describe the impact of freeze-thaw upon particle roundness The conceptual diagram is explained as follows: As a result of the freeze-thaw effect particles break up and the roundness decreases and the size decreases. In an aeolian setting there are three methods by which soil particles are transported by wind including surface creep, saltation and suspension 15,27 and 28 .1 The fragmented particles are characterized by edges with small roundness. Because of the size-selective nature of transport and saltation abrasion, Eolian ecosystems are the majority of subrounded, well-sorted grains 15,16,17,18 . Repeated freeze-thaw cycles result in fragmentation of the edges of particles and an increase in roundness.1
The roundness of aeolian deposit particles increases as the distance to the area of the source 30 . In the study of Fig. 6, it is conclusively concluded that repeat freeze-thaw cycles may cause an increment or decrease the particle roundness. Similarly, when the transport mode is fluvial transport, the particle size decreases and the roundness and sphericity increase due to the shape sorting and increase of transport distance 31,32,33,34,35,36,37,38 .1 Figure 7 shows that with repeated freeze-thaw cycles, particle size can change as roundness decreases for the same particles. In the previous literature we can see that both wind and fluvial transport may cause growth of the roundness of particles. To analyze the relationship between the size of the particle and roundness in freeze-thaw cycles, a chart of roundness and size of particles changes for all types of soil following freeze-thaw cycles has been drawn (Fig. 8).1
The freeze-thaw effect alters the particle’s morphology that differ from aeolian or river transport methods, and have distinct specific characteristics. Changes in the size and roundness for each type of soil following freeze-thaw cycles. ( an Specification (L) and B (Specimen (CS) (VFS); the c Specificimen (VFS) (d the Specimen (FS)).1 The process of determining the size of the particle dimension, aspect ratio , and roundness changes due to freeze-thaw effect are depicted in the concept diagrams.
In figure. 8, the green dot line shows the initial distribution of roundness in the specimen. The diagram is shown in Fig. 10. It is apparent in the graph that the roundness decreases in loess as particles grow in size, whereas rough sand’s roundness, extremely fine sand and fine sand do not diminish, but is fluctuating within a particular interval.1 There are two primary stages of the freeze-thaw phenomenon that causes particle size, aspect ratio , and roundness alteration. In general, roundness for very fine sand is by far the biggest, then fine sand and coarse sand.
In the first caused by the tension in the temperature and the alteration of the water phase on the surface, the cracks appear in the surfaces of the coarse particles.1 The least round is the loess. When water penetrates into the cracks the water phase transforms into an ice (volume rises by 9%) which causes the expansion and penetration of the cracks. With the increasing number of freeze-thaw cycles the roundness of the various particle sizes decreased or increased as a result of the rounding or fragmentation of the particles that resulted in the change in roundness.1 This eventually results in particle fragmentation. particle size shrinks, roundness, and aspect ratio changes. When you go through the 10th freeze-thaw, it is apparent that the roundness and roundness for loess as well as fine sand is less than the original value while the roundness of loess after other freeze-thaw cycles are greater over the value of the first.1
In the second phase with the freeze-thaw process, the sliding of particles happens, the edges of particles gets broken, while the roundness the particles increase. This is due to the fact that the 10th freeze-thaw caused the particles to fragment which resulted in a reduction in roundness. When repeated freeze-thaw actions are performed, an aspect ratio for particles diminishes, and the proportion of particles that have an aspect ratios that is 1.26 is the most common.1 The circularity of the coarse as well as extremely fine sand varied based on the amount of freeze-thaw cycles. Conceptual diagram of freeze-thaw effects altering particle aspect ratio as well as circularity (Note that this drawing can be applied to larger sizes of particles). The overall roughness and roundness of all four samples was increased with each freeze-thaw cycle for 100 cycles.1
In the roundness analysis of four samples it was discovered in the course of 100 freeze-thaw cycles, the roundness of the particles is increased. Then, you can take the change of the specimen (FS) after various freeze-thaw cycles as an example to examine the evolution of its roundness. In other words, the cryogenic weathering process can cause an increase in roundness of the particle.1 The images of the specimen (FS) after various freeze-thaw cycles have been obtained using the use of a particle image processor (a Malvern Panalytical). This is consistent with the fact that when the transport is a fluvial medium The roundness of particles increase following a certain distance of flow transport .1 To make it easier to analyze, a single particle images are removed from the particle image to facilitate analysis.
This is in accordance by the observation that the most important shape of particles is well-sorted subrounded particles in the aeolian environment 15,16,17,18 . Single particle images from 5,10,50 , and 100 freeze-thaw cycles have been extracted from the respective images following various freeze-thaw cycles.1 So, the increased roundness of particles following 100 freeze-thaw cycles is not used as a basis to decide whether the particles are subject to cryogenic weathering. In Figure.
9 it can be evident that the roundness particles increased following five freeze-thaw cycles. However, with repeated freeze-thaw effects as well as the particles’ roundness getting larger, particle aspect ratio also diminished.1 Following the 10th freeze-thaw cycle the particles began to fragment with the diameter of the particles diminished, i.e., the result of the freeze-thaw effect that led to the diminution of particle’s roundness in Figure. 7.