Freeze-thaw Cycle Test Research Articles

Experimental Study on Engineering Geological Properties of Sandstone

Based on field survey sampling and indoor test of four big quarry rock in Wulumuqi, rock's engineering geological properties is system analyzed. Investigation and test results show that there is mainly sedimentary sandstone in the area, the composition of the substance is mainly debris, feldspar and quartz.Debris content of 60% or more, feldspar and quartz content of about 30%, cementing material is mainly made up of argillaceous and carbonate class whose ratio is about 10%. The compressive strength is higher in the natural state, the general in between 30 MPa-90MPa. In different moisture content state the compression strength are very different.Compared saturated state to dry state, the compressive strength reduced by about 40%. Tensile strength, flexural strength, shear strength and elastic modulus increase with increase of compressive strength. The same kind of rock in the same moisture content which tensile strength is only the 1/15-1/25 of the compressive strength, the flexural strength is the 1/4-1/7 of the compressive strength. Sandstone frost resistance is better, after 25 times the freeze-thaw cycle test, its strength is lower slightly and quality is not damaged.

Durability of lining concrete of subsea tunnel under combined action of freeze-thaw cycle and carbonation

Through the fast freeze-thaw cycle test, accelerated carbonation test, and natural carbonation test, the durability performance of lining concrete under combined action of freeze-thaw cycle and carbonation were studied. The experimental results indicate that freeze-thaw cycle apparently accelerates the process of concrete carbonation and carbonation deteriorates the freeze resistance of concrete. Under the combined action of freeze-thaw cycle and carbonation, the durability of lining concrete decreases. The carbonation depth of lining concrete at tunnel openings under freeze-thaw cycles and tunnel condition was predicted. For the high performance concrete with proposed mix ratio, the lining concrete tends to be unsafe because predicted carbonation depth exceeds the thickness of reinforced concrete protective coating. Adopting other measurements simultaneously to improve the durability of lining concrete at the tunnel openings is essential.

Study on Frost Resistance of High Performence Concrete Resistance to Chloride Ion

Taking bridge pile of Beijing-Shanghai high speed railway as background, this paper studies frost resistance of high performance concrete resistance to chloride ion, including double-doped mineral (fly ash and slag powder) concrete, two minerals and preservative composition concrete. Quick frost method was adopted in the freeze-thaw cycle test, and frost resistance of high performance concrete was assessed by relative dynamic modulus of elasticity and mass loss ratios. Meanwhile, the electric flux values of specimens were measured after freeze-thaw cycles for assessing chloride ion penetration. Test results show: The frost resistance of both C35, C50 double-doped mineral concrete and C35 two minerals and preservative composition concrete is good, and chloride ion permeability is very low after freeze-thaw cycles.

Durability Tests of a Fiber Optic Corrosion Sensor

Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR) and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively.

Experimental Study on Frost Resistance Properties of Pumice Mixed Aggregate Concrete

Different amount of pumice were used to replace gravel to make mixed aggregate concrete, the fast freeze-thaw cycle test were conducted and the influence of pumice rate substitution to the frost resistance properties of concrete were studied.The mass loss rate, strength loss and relative dynamic elastic modulus were regarded as the evaluation index of frost resistance properties of concrete. Results showed that the mass loss rate and strength loss rate gradually decreased and the relative dynamic elastic modulus gradually increased with the increase of pumice rate, the mass loss rate, strength loss rate and the relative dynamic elastic modulus gradually decreased with the increase of freeze-thaw cycles. Polypropylene fibers could reduce the strength loss rate, improved the relative dynamic elastic modulus, but had little effect to improve the mass loss. Through the frost resistance, the frost resistance of concrete improved with the increase of pumice content, at the same time, polypropylene fiber also could improve the frost resistance of concrete.

Low Temperature Performance of Fiberglass Geogrid

The tensile test to the fiberglass geogrid had been carried on, in the normal temperature, the low temperature, the water immersion, the freezing and the freeze-thaw cycle and so on conditions. The results indicated, the fiberglass geogrid had achieved saturated after been immersed 12h, the water absorption was about 20%, the tensile strength reduced approximately 80%; the tensile strength was dropped slightly on the next freezing test and the freeze-thaw cycle test. So it could be stated that the fiberglass geogrid had the good low temperature performance. Then the interlaminar shearing test had been conducted in the different temperature to the composite structure in which the fiberglass geogrid was laid or not. The result showed that the interlaminar shearing strength had weaken about 20% when laid down the fiberglass geogrid, and along with temperature drop, the shearing strength increased gradually. This research provide the reference for used the fiberglass geogrid correctly in the cold region, had great practical value.

Microemulsions of Potassium Oleate, Tween-20, Propylene Carbonate, and Ethylene Glycol as Drug Vehicles for Mefenamic Acid

Different microemulsions were prepared with and without mefenamic acid (MFA). The base microemulsion was mainly composed of distilled water; the aqueous phase, propylene carbonate; the oil phase, potassium oleate; the surfactant, and finally di-ethylene glycol; the cosurfactant. The effect of mixing ionic (potassium oleate) with nonionic (Tween-20) surfactant was investigated via constructing the phase diagrams of such systems. Changes in conductivity and viscosity of the freshly prepared microemulsion over time were monitored as an indication for the stability of the microemulsion. Measurements were carried out at room temperature, after a freeze-thaw cycle and also after storage for 3 days at 60°C, where the latter is treated as an accelerated test for the time-temperature effects on the stability of a microemulsion. It was found that a set of surfactants, instead of a single surfactant, and inclusion of cosurfactant resulted in a broader region where a stable microemulsion is predominant. At a mass ratio of 1:2 of potassium oleate to Tween-20, O/W microemulsions were found to have maximum stability among all examined systems, under the accelerated test, such that they have a minimum portion of combined surfactants and cosurfactant of 60 wt% and maximum of 80 wt%. With the aforementioned specifications, no phase separation and neither significant change in the conductivity nor in the viscosity was observed in any of the examined systems after subjecting them both to the accelerated and freeze-thaw cycle test, indicating that such systems were thermodynamically stable. Samples of micro emulsions passing previous tests were further subjected to an acidic medium by dispersing 1 g of MFA-containing microemulsion in 10 g HCl solution (pH 1) in a shaking water bath at 37°C, for a 6 hour period. The maximum solubility of MFA in a stable microemulsion was approximately 5 wt%, evaluated at room temperature.

Durability of Green High Performance Alkali-Activated Slag Pavement Concrete

Green high performance alkali-activated slag pavement concrete(ASC) was prepared by adding Na2SiO3 and NaOH complex activator in slag. Physical, mechanical performance and durability of ASC were studied by workability, strength, hydrostatics and chlorin ion penetrability, fast freeze-thaw cycle tests and abrasion resistance tests. The results show that slump of ASC exceeds 160mm, fluidity and workability is excellent. 28d compressive and flexural trength of AAC are 91.9MPa and 8.5MPa, 7d compressive and flexural strength are 84.8MPa and 7.6MPa, which belongs to high–early strenth concrete. And its impermeability rank exceeds S40, chlorin ion impermeability is excellent, 6h eletricity is 1751～1894 coulomb, and its anti-frozen rank exceeds F300, which can meet the anti-frozen requirements in frore area. Depth of abrade slot is 0.45～0.96mm, abrasion resistance of ASC is 4.99, so its physical, mechanical performance and durability are superior to traditional portland concrete.

Preliminary Approach to Mechanical Characteristics of Cement Mixed Superfine Iron Tailings

A large number of specimens with different contents of cement mixed superfine tailings, which took superfine iron tailings as aggregate, were produced to carry out a series of experiments on the mechanical properties of different ages and freeze-thaw cycling tests. The strength, load -deformation curve, frost resistance and other performances of cement mixed superfine tailings were obtained. The experiment data were compared with cement mortar and cement-mixed soil ones under the same conditions. The results are listed as follows: on even ground, the strength of cement-superfine tailings can be 4-6 times higher than that of cement-mixed soil, and about 10% lower than that of cement mortar; the relation of load-deformation and the characteristics of freeze-thaw cycles are basically the same as cement mortar under the same conditions.

Freeze–thaw cycle test and damage mechanics models of alkali-activated slag concrete

Alkali-activated slag concrete (ASC) was prepared by using slag and Na 2SiO 3, NaOH complex activator. Freeze–thaw resistance, microstructure, performance mechanism, inner freeze–thaw damage distribution and mechanics models of ASC were investigated by freeze–thaw cycle, SEM and EDS tests. The experimental results show that ASC has excellent freeze–thaw resistance with frost-resisting grade of F300 at lowest; hydration products of ASC are mostly C–S–H(I) with low Ca/Si, alkaline aluminosilicate and zeolite mineral, it does not have Ca(OH) 2 and transition strip, compact degree and uniformity of structure are better, and its high compressive strength (90 MPa) also makes high freeze–thaw resistance, therefore, ASC has excellent freeze–thaw durability; freeze–thaw damage mechanics models of ASC were established by using relative dynamic elasticity modulus, dynamic elasticity modulus attenuation model is superior to accumulative freeze–thaw damage model, power function model is superior to exponential function model with better precision and relativity, and the models can reflect freeze–thaw damage rule and degree accurately.

The effect of welding degree on geotechnical properties of an ignimbrite flow unit: the Bitlis castle case (eastern Turkey)

Ignimbrites are associated with nearly most of the world’s volcanoes and are defined as a deposit from pyroclastic density currents. They consist predominantly of pumiceous lapilli and blocks, and glass shards, which shows evidence of having been emplaced as a concentrated hot and dry particulate flow. These rocks are widely used as building stone especially in ancient buildings. Bitlis valley is covered by ignimbritic products, derived from Nemrut stratovolcano, one of the significant volcanic centers in Eastern Anatolia. The Bitlis ignimbrite is separated into lower level (LL), middle level (ML) and upper level (UL) according to color, welding degree and structural features. All three levels were used extensively in many parts of the Bitlis castle as masonry materials. Studies were carried out on mineralogical and geochemical composition and on physical and mechanical properties of the ignimbrites. In addition, a freeze–thaw cycle test was executed. There are no considerable differences in mineralogical composition among the levels of ignimbrite. All levels contain plagioclase, sanidine, pyroxene, and opaque mineral. In addition, anorthoclase and quartz are seen. In general, the LL of ignimbrite shows relic perlitic and eutaxitic texture, whereas eutaxitic and vesicular texture are commonly developed in the ML and UL, respectively. Lower, middle, and upper level ignimbrite samples display similar and limited compositional spread in terms of major oxide elements. They have trachyte composition. Building stones can be classified according to mineralogy, mechanical and physical properties and processing types. Mechanical and physical properties are very important with respect to stone quality/durability. The mechanical and physical properties of the ignimbrites are controlled by the welding degree. It was found that increasing welding degree from UL to LL correlates with increasing density, compressive strength and slake durability index and with decreasing porosity. The Bitlis ignimbrites have turned out as susceptible to freeze–thaw cycles.

Damage Model and Damage Mechanical Characteristics of Loaded Rock under Freeze-Thaw Conditions

Considering the heterogeneous characteristics of rock at mesoscopic level, the damage propagation constitutive relation and evolution equation of freeze-thaw and loaded rock were established by using the theory of macro phenomenological damage mechanics and the generalized theory of strain equality. The evolutionary mechanisms of micro-structural damage and materials mechanical properties for the loaded rock were discussed under freeze-thaw condition, verified by experimental results of the freeze-thaw cycle and compression test of rock. It is shown that the freeze-thaw and loaded damage model can represent the complicated relations among the freeze-thaw, load and the damage inside the rock, reveal the coupling failure mechanism of macroscopic rock under the freeze-thaw and load from the micro-damage evolution. The combined effect of freeze-thaw and load exacerbates the total damage of rock with obvious nonlinear properties, but the coupling effect weakens the total damage. The lithology and initial damage state of the freeze-thaw and loaded rock in engineering structures in cold regions determine the weights of influence factors to mechanical properties, including environmental factor, loading factor and the coupling effects, so the rock performances different damage mechanical characteristic.

Solidification of arsenic and heavy metal containing tailings using cement and blast furnace slag

The objective of this study is to examine the solidification of toxic elements in tailings by the use of cement and blast furnace slag. Tailings samples were taken at an Au-Ag mine in Korea. To examine the best mixing ratio of tailings and the mixture of ordinary Portland cement (OPC) and blast furnace slag (SG) of 5:5, 6:6, 7:3, and 8:2, the 7:3 ratio of tailings and OPC+SG was adapted. In addition, the mixing ratios of water and OPC + SG were applied to 10, 20, and 30 wt%. After 7, 14, and 28 days' curing, the UCS test was undertaken. A relatively high strength of solidified material (137.2 kg cm⁻² in average of 3 samples) at 28 days' curing was found in 20 wt% of water content (WC). This study also examined the leachability of arsenic and heavy metals (Cd, Cu, Pb, and Zn) under the Korean Standard Leaching Test, and it showed that the reductions in leachabilities of As and heavy metals of solidified samples were ranged from 76 to 99%. Thus, all the solidified samples were within the guidelines for special and hazardous waste materials by the Waste Management Act in Korea. In addition, the result of freeze-thaw cycle test of the materials indicated that the durability of the materials was sufficient. In conclusion, solidification using a 7:3 mixing ratio of tailings and a 1:1 mixture of OPC + SG with 20% of WC is one of the best methods for the remediation of arsenic and heavy metals in tailings and other contaminated materials.

Excessively Wet Subgrade Improvement with 100% Industry By-Products for Heavy Traffic Pavement – II. Mechanical Behavior and Durability of Stabilized Soils

The workability of excessively wet subgrade can be effectively improved by using a “green materials” based entirely on industry byproduct of combination of fly ash (FA) with carbide lime (CL) and flue gas desulfurization gypsum (FGDG). This paper presents the results of a further systematic investigation on the mechanical behavior and durability of FA/CL/FGDG treated silt from Dezhou in Shandong province. FA, CL and FGDG were added at 3 levels in percentages of 8%-24%, 2%-6% and 1%-3% by dry weight of the soils, respectively. The unconfined compressive strength as well as splitting tensile strength (STS), volumetric expansion (VE), California bearing ratio (CBR), dry-wet cycles test and freeze-thaw cycles test were performed. The best strength of 0.802MPa was achieved for 24%FA/6%CL/1%FGDG treated soil, while the 16%FA/6%CL/1%FGDG treated soil also produce good strengths of 0.742MPa, after 7 days curing. STS keeps increasing with curing period in the first 8 weeks throughout the investigation. According to the VE test, a mellowing period may help prevent swelling from ettringite precipitation by letting these minerals form and hydrate before compaction. The FA/CL/FGDG treated soil has a better durability with strength loss ratio less than 15% after 10 wet-dry cycles, and the maximum weight loss around 25% after 10 freeze–thaw cycles. CBR decreases with decrease of compaction degree, but the values are still around 70 even in a poor compaction degree of 93%, meeting the general requirements of subgrade. So, if the silt subgrade is in excessively wet state and could not be compacted to the required density, the modified subgrade would still serve as a strong platform and could provide necessary support for pavement.

Freeze-Induced Damage and Purge Based Mitigation in Polymer Electrolyte Fuel Cells

The objective of this work is to investigate damage of polymer electrolyte fuel cell (PEFC) materials subjected to freeze-thaw cycling. Effects of microstructures of membrane electrolyte assembly (MEA) and diffusion media (DM) were investigated by ex-situ freeze-thaw cycling tests and revealed a strong direction for the material choices in the PEFC and confirmed the previous computational model in the literature (1, 2). Specifically, the membrane electrode assemblies were found to be a source of water that can damage the catalyst layers under freeze/thaw conditions. Damage was found to occur almost exclusively under the channel, and not under the land. Conceptually, the best material to mitigate freeze damage is a crack free virgin catalyst layer on a reinforced membrane that is as thin as possible, protected by a stiff diffusion media. In addition to ex-situ cycling test, freeze-thaw cycling of fuel cells was also carried out. Without purge of liquid water during the shut down, the fuel cell experienced irreversible damage. Removal of free liquid water from the catalyst layer pores is integral to the reduction of freeze-induced damage.

Influences of a new admixture MX on concrete durability

The performance of concrete with a new admixture MX was studied by using the freeze-thaw cycle, permeability and chemical attack test. The experimental results show that MX improves the durability of concrete. Within the optimum proportion ranges from 0.1% to 1%, the compressive strength of concrete after freeze-thaw is increased by 20%–50%, and Young’s modulus can be increased by 3.76–5.64 times. The strength and weight loss of concrete with 0.4% MX are respectively decreased by 28% and 60% after hydrochloric acid attack. The strength and weight loss of concrete with 0.4% MX are decreased by 5%–20% after sulfuric acid and sodium sulfate attack. The permeability of concrete with 1% MX at 28 days can be decreased by more than 30%. The investigation of the negative temperature property of MX and analysis on concrete composition and microstructure by MIP reveal that the heat conduction is resisted and the freezing procedure of solution in concrete pore is retarded due to the adding of MX. Moreover, the pore structure of concrete with MX is improved, thus improving the durability. Based on this study, a resistance model of MX to block the heat and mass transference was proposed, and the mechanism of durability improvement of concrete with MX was explained.

The long-term behaviour of an aluminium-reinforced polyethylene pressure pipe

The long-term behaviour of an aluminium-reinforced polyethylene pressure pipe has been explored by undertaking stress rupture tests at 60 and 80 °C. The results of the tests showed these macrocomposite pipes have a time-dependent strength, such that with an increasing time under load the strength declined. In addition the pipes were weaker at 80 °C when compared to the 60 °C strength. The analysis of the influence of time and temperature on strength showed these multilayer pipes can be considered to behave as do conventional homogeneously structured plastic pipes, and that to describe the influence of time on the pipe strength, the accepted procedures developed for conventional plastics pipes can be applied. In addition the mode of failure of the pipes was examined. Pipe failure initiates by the strain-controlled failure of the reinforcing aluminium layer. The polyethylene layers then fail almost instantaneously in a ductile mode. This analysis of the mode of failure was supported by freeze-thaw cycling tests to − 25 °C and the 60 and 80 °C stress rupture tests.