Freeze-thaw Effect Research Articles

Research on Freeze-Thaw Cycles of Expansive Concrete in Civil and Repairing Engineering

In this paper, large areas of defects such as pitting surface and holes produced after pouring concrete in civil engineering are simulated. The orthogonal method is used to produce expansive concrete which has a higher strength grade and a smaller aggregate size than original concrete for repairing. The effects of different water reducing agent content, expansive agent content, fly ash content and sand ratio on freeze-thaw cycle are analyzed. Finally, it recommends the best concrete mixing proportion and verifies repairing effect by comparing with original concrete of nonrepair. Results indicate that the mixing proportion which means 5% expansive agent content, 1.2% water reducing agent content, 20% fly ash content and 30% sand rate can obtain good antifreeze effect. In addition, the influence of water reducing agent on freeze-thaw effect is more obvious than expansive agent. Moreover, a greater content of expansive agent can not lead to a better effect of freeze-thaw cycles.

Multiscale analysis of freeze–thaw effects induced by ground heat exchangers on permeability of silty clays

The freeze–thaw cycles artificially induced in the ground by ground source heat pump systems working at sub-zero temperatures, or during underwater soil excavation, could cause unwanted permanent effects on the hydro-mechanical behaviour of the surrounding deposits. Cohesive deposits present a specific sensitivity to these processes connected to phase changes occurring in the interstitial fluid. The experiments conducted on normally consolidated cohesive soils point out that freeze–thaw cycles can cause a hysteretic increase in vertical permeability of about one order of magnitude, despite a significant concurrent reduction in void ratio. Although the induced freeze–thaw processes are quite constrained close to the borehole heat exchanger, the vertical permeability increase may lead to the risk of connecting aquifers previously separated by cohesive layers, with an overall effect that increases according to the number of probes in the array. Permeability variation appears to be due to the irreversible alteration of the microstructure provoked during the development of freeze–thaw processes. In this paper, the changes of the macroscale hydraulic conductivity are related to changes in the porous microstructural variations, detected in a wide dimensional range by means of a combination of X-ray computed micro tomography, scanning electron microscopy and mercury intrusion porosimetry.

Freeze-thaw performance of phase change material (PCM) incorporated pavement subgrade soil

Phase Change Materials (PCMs) can store and release large amounts of energy in the form of latent heat during their phase changes, which could be utilized in controlling the freeze-thaw impact on pavement foundation systems. Untreated, and Class C fly ash-treated loess soil amended with three different dosages of paraffin-based liquid, and microencapsulated PCMs were evaluated using unconfined compression, volume change, and frost heave tests. The results of this research support the use of PCMs in controlling the freeze-thaw effect on subgrade soil. Further recommendations are provided on PCMs selection, composite type PCMs, incorporation method, and chemical stability.

Review on the modelling methods for the frost action characterization in cementitious materials at different scales

Experimental studies on the frost action in concrete have showed a complex behaviour due to a high thermo-hydro-chemo-mechanical coupling. Many researchers have developed models to simulate freeze-thaw effects in cementitious materials. They showed the difficulties to take into account all phenomena: hydraulic, hydrostatic and osmotic pressures into pores; swelling and shrinkage; scaling, etc. Some researchers have firstly proposed descriptive models with the objective to reproduce the macroscopic observations, by calibrating the behaviour law and to show the influence of each parameters. Other researchers have proposed predictive models without calibration but with probabilistic methods. The different models show interesting results but are limited to few physical phenomena listed above. This paper presents a review on these different modelling methods and the limitations of each model. A short discussion is given to suggest a coupling method to consider all physical phenomena.

Drying Shrinkage Reducing Agent Easing the Frost Damage Deterioration due to the Freeze-thaw Effect

Drying Shrinkage Reducing Agent Easing the Frost Damage Deterioration due to the Freeze-thaw Effect

Impact of post-collection freezing delay on the reliability of serum metabolomics in samples reflecting the California mid-term pregnancy biobank.

Population-based biorepositories are important resources, but sample handling can affect data quality. Identify metabolites of value for clinical investigations despite extended postcollection freezing delays, using protocols representing a California mid-term pregnancy biobank. Blood collected from non-pregnant healthy female volunteers (n = 20) underwent three handling protocols after 30min clotting at room temperature: (1) ideal-samples frozen (- 80°C) within 2h of collection; (2) delayed freezing-samples held at room temperature for 3days, then 4°C for 9days, the median times for biobank samples, and then frozen; (3) delayed freezing with freeze-thaw-the delayed freezing protocol with a freeze-thaw cycle simulating retrieved sample sub-aliquoting. Mass spectrometry-based untargeted metabolomic analyses of primary metabolism and complex lipids and targeted profiling of oxylipins, endocannabinoids, ceramides/sphingoid-bases, and bile acids were performed. Metabolite concentrations and intraclass correlation coefficients (ICC) were compared, with the ideal protocol as the reference. Sixty-two percent of 428 identified compounds had good to excellent ICCs, a metric of concordance between measurements of samples handled with the different protocols. Sphingomyelins, phosphatidylcholines, cholesteryl esters, triacylglycerols, bile acids and fatty acid diols were the least affected by non-ideal handling, while sugars, organic acids, amino acids, monoacylglycerols, lysophospholipids, N-acylethanolamides, polyunsaturated fatty acids, and numerous oxylipins were altered by delayed freezing. Freeze-thaw effects were assay-specific with lipids being most stable. Despite extended post-collection freezing delays characteristic of some biobanks of opportunistically collected clinical samples, numerous metabolomic compounds had both stable levels and good concordance.

Freeze-thaw effect on the durability of binary cements containing activated coal-mining waste

The present work contains an approach to the evaluation of binary cements prepared with a 20% substitution of coal-mining waste and their behaviour under a maximum of 300 freeze/thaw cycles. Mineralogical studies are conducted, as well as tests on mass variations, compressive strength, microporosity, the dynamic modulus of elasticity, and SEM morphologies. It is important to highlight that the partial replacement of cement by 20% of activated coal waste, does not affect the durability against freeze/thaw cycles, since they show a fairly similar tendency to the reference mortar under extreme temperature changes.

An Investigation of the Factors Affecting Saline Ice Melting Processes and Desalination

In this study, a laboratory simulation experiment is undertaken to examine five factors affecting the melt‐water quality and quantity changes during the melting process of saline ice: salinity, freezing/melting temperature, ion composition, and the freezing method. A field experiment is conducted to evaluate the freeze–thaw effects on desalination of saline water under natural conditions. The results show that for all treatments, the melt‐water salinity sharply decreases during the first half of the melting process. Saline ice with a higher original salinity have higher melt‐water salinity. The desalination rates increase with the original salinity when water salinity is less than 15 g L−1, but production of available water shows the opposite trend. Saline ice frozen at −15 °C increases production of available water by ≈23.66% relative to ice formed at −10 and −20 °C. Nearly 25% of available water is lost during melting when the ambient temperature increases to 30 °C. The addition of Ca2+ significantly reduces desalination rates compared with saline ice composed of solely NaCl. The unidirectional‐freezing method significantly accelerates the salt exclusion, and increases desalination rates. The results of field experiment shows that the salinity and sodium adsorption ratio (SAR) sharply decreases with the saline ice melting. These results indicate that saline water con be desalinized by the freeze–thaw process, and the desalinating efficiency is controlled by the salinity of water, freezing and melting temperatures, the freezing method, and original ions composition.

Effect of Freeze-Thaw on a Midtemperate Soil Bacterial Community and the Correlation Network of Its Members.

Freeze-thaw (FT) events can influence soil functions. However, the overall impact of FTs on soil bacterial communities, especially in temperate regions, remains unclear. In this study, soil samples were collected from a midtemperate region in the northeast of China, and three incubation tests were then designed with varied FT amplitudes (i.e., at a freezing temperature of −15, −9, and −3°C, respectively), frequencies of FT cycles (i.e., under one, six, and 15 FT cycles, respectively) and soil water content (SWC) values (i.e., at 10 and 30% SWC, respectively). High-throughput sequencing of 16S rRNA gene amplicons was performed and the functional profile was further predicted based on these data, in addition to examinations of bulk microbial properties. Data analyses suggested that, first of all, the FT amplitude significantly influenced the bulk microbial properties and bacterial community (composition and function); certain taxa showed a nonlinear response to the three amplitudes. Next, compared to a single FTC, multiple FT cycles had only minor effects on the bacterial functional capabilities, although the bulk microbial properties changed significantly after multiple FT cycles. In addition, the bacterial response to FTs was influenced by the SWC, characterized by the significantly different bacterial community structures (composition and function) and the opposite trends of enzyme activities. Finally, RDA plots and a correlation network assembled data from all soil samples across the three tests and suggested that bacterial response trajectories changed because some species were influenced mainly by other species (i.e., biotic environment) during FT processes.

Experimental inference on dual-porosity aggravation of soft clay after freeze-thaw by fractal and probability analysis

Variation of micro-structure is very important and virtually the internal nature of macro-behaviours, especially when the macro phenomenon is complex and the mechanism is obscure. The dual-pore structure can be regarded as a special pore structure in clay with a primary network of large inter-aggregate pores overlapped by a secondary network of small intra-aggregate pores. The main hydrodynamic and mechanical properties of soils appear to be largely controlled by this hierarchical partitioning of porosity. Aiming to more specific mechanical properties control during artificial ground freezing from microstructure aspect, this paper focuses on the pore-structure characteristics and computational inference of soft clay after the action of artificial ground freezing. Mercury Intrusion Porosimetry (MIP), as a direct quantization method, was employed to obtain the soil pore-size distribution. And scanning electron microscopy (SEM) was conducted as well, as visible supplementary to describe and qualitatively characterize the microporosity structure. Based on these two aspects, experimental results show a dual-porosity characteristic aggravated after artificial freeze-thaw. Then the influence factor analysis of freeze-thaw effects including different freezing temperature and freezing time, was discussed under uniform design methodology. The influence of each parameter respectively on the variation of dual-pore structure has been discussed to provide valuable reference for AGF practice. Finally, a new comprehensive dual-porosity computational model of soft clay on freeze-thaw effects is developed based on fractal and probability analysis. The application of this model is discussed for the further study.

Effect of freezing-thawing on concrete behavior

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-thawing cycles did not effect on the compressive strength of the mixes and the durability of the mortar and the concrete. It is recommended that more than 300 freezing-thawing cycles must be avoided.

Durability properties of concrete containing metakaolin

The main aim of this study is to investigate the possible effects of metakaolin on strength and durability properties of concrete. For this purpose, concrete mixtures are produced by substituting cement with metakaolin 0, 5, 10 and 20% by weight. The amount of binder for the concrete mixtures are 300 and 400 kg/m3 with a constant water to cement ratio of 0.6. Compressive and bending strengths, freeze-thaw and high-temperature resistances, capillary coefficients and rapid chloride permeability properties were determined and compared each other. Because of all the experiments conducted, it has been found that the use of metakaolin as a pozzolanic additive in concrete have positive effects especially on compressive and bending strengths, capillary, rapid chloride permeability, freeze-thaw resistance, and high temperatures, up to 800oC. The results indicated that the performance of concrete can be enhanced by metakaolin. Particularly, compressive strength and durability properties have found to be improved with increasing metakaolin content which is attributed to pozzolanic activity and filler effect. Furthermore, metakaolin has relatively positive impacts under elevated temperatures and freeze-thaw effects. However, almost all the strengths of entire concrete specimens are lost at 800

Atmosphere–vegetation–soil interactions in a climate change context; impact of changing conditions on engineered transport infrastructure slopes in Europe

In assessing the impact of climate change on infrastructure, it is essential to consider the interactions between the atmosphere, vegetation and the near-surface soil. This paper presents an overview of these processes, focusing on recent advances from the literature and those made by members of COST Action TU1202 – Impacts of climate change on engineered slopes for infrastructure. Climate- and vegetation-driven processes (suction generation, erosion, desiccation cracking, freeze–thaw effects) are expected to change in incidence and severity, which will affect the stability of new and existing infrastructure slopes. This paper identifies the climate- and vegetation-driven processes that are of greatest concern, the suite of known unknowns that require further research, and lists key aspect that should be considered for the design of engineered transport infrastructure slopes in the context of climate change.

Effect of fly ash on freeze–thaw durability of concrete in marine environment

Deterioration of structural concrete exposed to freeze–thaw cycles is one of the most important durability problems under subzero temperature conditions. It becomes more devastating when associated with marine environment. Supplementary cementitious material such as fly ash may be used as partial replacement of cement for making more dense, less absorptive and less permeable concrete which improve freeze–thaw durability. This paper presents a part of an experimental study on the freeze–thaw effect of concrete specimens exposed to artificial seawater simulating marine environment and plain water over 360 cycles. Three different grades of concrete M38, M33 and M28, each with four different fly ash replacement level, 20, 30, 40 and 60% were used for the experimental programme. The deteriorative effects were measured by studying weight and volume change, compressive strength, permeability characteristics and rapid chloride penetration resistance of the deteriorated test specimens. the optimum amount of cement replacement is reported to be around 30 to 40%. The study reveals that fly ash concrete has better resistance against freeze–thaw deterioration due to pozzolanic activity of fly ashes that creates more calcium silicate hydrate gel and fills pore spaces, which can effectively reduce the corrosion of the embedded steel reinforcement.

The effect of soil water content and erodibility on losses of available nitrogen and phosphorus in simulated freeze-thaw conditions

The effects of soil water content (SWC) and erodibility on available nutrient losses, as well as the influence of freeze-thaw on available nitrogen (AN) and phosphorus (AP) losses from loess soils have rarely been considered. We report on a series of laboratory simulation experiments conducted to determine SWC and soil erodibility effects on AN and AP losses under freeze-thaw conditions. Effect of freeze/thaw compared to unfrozen, two treatments were set (LS: Loess that unfrozen; FTS: Freeze-thawed a loess), and we studied five SWCs, between 10% and 30%, and we divided SWCs into two groups: lower water content areas (10% and 15%), higher water content areas (20%, 25%, and 30%). Overall, significant differences in runoff/sediment associated AN and AP concentrations of different SWCs for two treatments (p < 0.05) were noted, while the relationship between SWC and AN and AP loss show a quadratic function change trend (R2 > 0.8). Largest runoff-associated AN and AP losses were found when the SWC was 30% and the largest sediment-associated AN and AP losses were found when the SWC was 10% in the two treatments. The soil erodibility factor (K) of the LS was less than that of the FTS when the SWC was low, and greater in a high water content area. The influence of runoff on sediment was positively linear. The absolute slope of the regression line between runoff rate and sediment yield rate is shown to be suitable as a soil erodibility indicator, while runoff-associated AN losses are mainly controlled by runoff rate, and are weakly affected by soil erodibility (p > 0.05). However, soil erodibility significantly influenced sediment-associated AP losses (p < 0.01), best described by a positive logarithmic relationship. Since the sediment-associated AP losses dominated the total AP losses for the two treatments, soil erodibility also exhibited a significant influence on total AP losses (p < 0.01). The freeze-thaw effect increased the total AN loss when the SWC was 15%, 20%, and 30%, and increased the total AP loss when it was 10% and 15%. The results of this study provide a better understanding of soil and available nutrient loss mechanisms under freeze-thaw conditions.

Characterization of freeze–thaw effects within clay by 3D X-ray Computed Tomography

Accurate quantification of moisture content redistribution and physical property change due to freeze–thaw is important for understanding frost heave and thaw settlement of fine-grained soils including clay. This paper presents 3D X-ray Computed Tomography (CT) data for a clay specimen before and after freeze–thaw and physical property data obtained by conventional laboratory testing, and the relationship among the date sets. Undisturbed clay specimens were subject to one-directional freeze–thaw in a closed system under different freezing temperatures to collect 3D X-ray CT images, and the variation in CT image intensity (CTI) before and after freeze–thaw were analyzed to reveal the spatial effects of freeze–thaw. Meanwhile, soil properties including moisture content, void ratio, and dry density were obtained for samples taken from different heights of the specimens with and without freeze–thaw to obtain their changes. Close correlations were observed between the physical property changes and the CTI variation. Linear equations were established between the changes of physical properties and the CTI variation. These equations could potentially be applied for high-resolution quantitative assessment of soil physical property changes due to freeze–thaw by using 3D X-ray CT. This study demonstrates that, compared with traditional test methods, CT scanning can be advantageous in revealing the internal change in soil physical properties due to freeze–thaw quantitatively and nondestructively.

Changes in the mineral element compositions of soil colloidal matter caused by a controlled freeze-thaw event

This study investigated the effects of a controlled freeze-thaw event on the mineral element compositions of colloidal matter in soil interstitial water. The experiment was designed to decouple the freeze-thaw effect from the warming effect by conducting sequential treatments. The temperate soil samples were incubated in a refrigerator at 2°C for four weeks and compared with those frozen at −20°C in the second week and thawed at 2°C for the following two weeks; this was done in order to study the freeze-thaw effect while minimizing the influence caused by warming. The soil samples incubated at 25°C in the fourth week after two weeks of the freeze-thaw treatment were compared with the freeze-thaw treatment group to investigate the warming effect. The laser-induced breakdown spectroscopy (LIBS) technique was used to analyze the relative elemental concentrations in the soil colloidal matter (SCM), which was collected on nylon membrane filters. The six predominant mineral elements were classified into two groups based on their distinct trends in response to the treatment conditions. The type 1 element (Si, Mg, Al) contents were decreased both by the warming condition and by the freeze-thaw treatment, whereas the type 2 element (Fe, Ca, Ba) contents were decreased by the freeze-thaw treatment but increased by the warming condition. Only type 1 elements showed positive correlations with the amount of organic carbon. From the results of the elemental compositions in SCM, the effects of a freeze-thaw event can be contradictory depending on the thawing temperatures.

凍結融解作用による透水係数の変化とアイスレンズの痕跡との関係

凍結融解作用による透水係数の変化とアイスレンズの痕跡との関係

MECHANICAL BEHAVIOR OF FLY ASH OR CEMENT AMENDED SAND-BENTONITE MIXTURES EXPOSED TO FREEZE-THAW ACTION AFTER LONG CURING

In construction of landfills, embankments and transportation structures, use of clay-sand mixtures are commonly preferred. To provide stability and enhanced engineering properties, stabilization with chemical admixtures is a reasonable approach. Unfortunately, freeze-thaw effect is a significant problem affecting soil behavior in cold regions. Studies on strength behavior of clay-sand mixtures stabilized using fly ash or cement exposed to freezing-thaw action is limited, and need further investigation. For this reason, in this study, using pozzolanic cement or class C fly ash as admixtures for clay-sand mixtures, an experimental framework was used to investigate the effects of clay content, admixture type, number of freeze-thaw cycles on strength of these mixtures. Sand specimens including 4, 8, 12 and 16% bentonite by weight were stabilized wih 3, 6, 9 % pozzolanic cement and 5, 10, 15, and 20 % class C fly ash by weight, specimens were prepared at optimum water content of mixtures. The specimens were then subjected to 1, 3 and 10 freezing / thaw cycles after 28 days of curing period. Freeze-thaw resistance of specimens was determined by application of unconfined compression tests. Experimental results revealed that, under the curing conditions adopted, cement and fly ash stabilization positively affects the strength of sand-bentonite mixtures and dominates the negative effects of freeze-thaw action. Pozzolanic cement stabilized samples provided higher freeze-thaw resistance compared to those amended with fly ash. Besides, analysis of secant modulus values revealed that, cement stabilized specimens showed a more rigid behavior after freeze-thaw action.

Compressive failure characteristics of yellow sandstone subjected to the coupling effects of chemical corrosion and repeated freezing and thawing

The coupling effects of chemical corrosion and freeze-thaw (F-T) cycling on the compressive failure characteristics of yellow sandstone were investigated. Results show that both chemical corrosion and minimum temperature in F-T cycles have adverse effect on the mechanical properties of yellow sandstone. With decreasing minimum F-T temperature and pH of the corrosive solution, peak stress and elastic modulus both decrease while peak strain increases, illustrating that the bearing capacity and deformation resistant capacity both decrease while ductility increases. During UCS tests, less damaged samples with a lower porosity tend to exhibit double-cone failure and contain smaller pores and more trans-grain fractures. Higher-damage samples with higher porosity tend to exhibit split failure or slope failure and contain larger pores and more inter-grain fractures. Chemical reactions between yellow sandstone and various chemical solutions are analyzed. F-T damage primarily occurs during freezing while chemical corrosion primarily occurs during thawing. Additionally, both the friction state and the internal microstructural damage influence the final failure mode. Results of this work can provide reference for the construction and development of rock structures in cold regions.