High Freeze-thaw Resistance Research Articles

Effect of Combination of Expansive Agent and Fiber on Freeze-Thaw Resistance of High-Strength Concrete at Dry Environment

This study employed a rapid freezing method to investigate the impact of individual additions of expansion agent, steel fibers, and High Elasticity Module Polyethylene Fiber (HEMPF), as well as their combinations, on the freeze-thaw resistance of High-Strength Concrete (HSC). The findings reveal that the non-air-entrained HSC of C80 exhibits excellent freeze-thaw resistance. However, this resistance is sensitive to the curing environment’s humidity. The expansion agent has a negative impact on the freeze-thaw resistance of HSC, while steel fibers and HEMPF fibers have positive effects. Combining HSC with an expansion agent and high elasticity modulus fibers ensures not only high freeze-thaw resistance but also a total alteration of humidity sensitivity, leading to an extended freeze-thaw life of HSC under dry curing conditions.

Sustainable performance of alkali-activated blast furnace cement concrete with high freeze-thaw resistance

The application of blast furnace cements with minor clinker constituent is an actual task due to their conformity with modern tendencies of sustainable development. The alkali metal compounds were proposed to increase activity of CEM III/C. The aim of the research was to investigate the effects of technological factors on porous structure of alkali-activated blast furnace cement concrete (further, AABFC concrete) to ensure its sustainable performance by criterium of freeze-thaw resistance in NaCl solution. The effects of fresh concrete consistency, aggregate state of alkaline component and curing conditions on sustainability of AABFC concrete were investigated. Increasing of fresh concrete consistency from class S1 up to class S4 due to chemical plasticization as well as application of alkaline component in dry form, in contrast to liquid form, ensures negative changes in porous structure of AABFC concrete. These changes cause decreasing of freeze-thaw resistance from mark F500 down to F200. It was revealed that hardening of plasticized AABFC concrete under normal conditions (t = 20±2 ° C, RH = 95±5%), compared with hardening in water or under steam curing (t = 85±5 ° C), ensures more effective porous structure which causes maintained freeze-thaw resistance of F300 in contrast to F200 and F250 agreeable.

Production and optimization of sustainable cement brick incorporating clay brick wastes using response surface method

This paper aims to fabricate and optimize eco-sustainable cement brick using different sizes of clay brick waste (CBW). The prime input factors of mixtures were clay brick powder (CBP) as a binder, fine-clay brick (FCB) as a fine aggregate, and coarse-clay brick (CCB) as a coarse aggregate, whereas the compressive strength was the main response of the generated eco-sustainable bricks. This was accomplished by utilizing the central composite design (CCD) and Response Surface Methodology (RSM) with Minitab-19. Twenty mixtures with CBW were generated and experimentally evaluated utilizing CCD concept in RSM. A multi-objective optimization approach was applied to obtain the optimum results for the input parameters. Based on an experimental program, the optimum mixtures were selected to investigate the physical and durability properties of the produced brick. The SEM test was also performed to determine the effect of the CBW particles on the microstructure of the brick. The life cycle assessment of mixtures is also performed in terms of global warming potential. The optimization showed that the input components CBP, FCB, and CCB had average optimum values of 21%, 0%, and 9.09%, respectively. The experimental results showed that employing CBW yields a durable and high freeze-thaw resistance of the eco-sustainable brick despite its high porosity and absorption. Furthermore, using cement brick with CBW particles is acknowledged as a more environmentally beneficial combination. The proposed models can speed up the process of mix design by using different sizes of brick waste to get the optimum eco-friendly cement brick properties.

Study into the freeze-thaw/ frost-salt resistance of high-strength B60–B100 concrete

Introduction. The development of the Arctic Region and oil and gas fields in the North Atlantic Ocean leads to an increase in the production of high-strength concrete structures. Thus, it is becoming increasingly vital to make such low-permeability concretes more freeze-thaw resistant.Aim. To conduct experimental studies for obtaining reliable data required to develop a standardized approach to the normalization of freeze-thaw / frost-salt resistance parameters characterizing high-strength concretes.Materials and methods. The study was performed using concretes of eight compositions (B60–B100 compressive strength grades). The freeze-thaw/frost-salt resistance of high-strength concretes was determined using the third rapid method involving the saturation, freezing, and thawing of samples in a 5 % sodium chloride solution, as well as assessment of freeze-thaw resistance in terms of strength, mass variation, and the dynamic modulus of elasticity. A variety of methods for increasing the water saturation of highstrength concrete were examined in order to expedite the testing process of high-strength concrete for freeze-thaw resistance.Results. The studies into the freeze-thaw/frost-salt resistance of high-strength B60-B100 concretes revealed their high freeze-thaw resistance. Following 37 freeze-thaw cycles, the lower confidence limit for the strength of test samples was higher than that of control samples multiplied by a coefficient of 0.9. The frost-resistance grade of these concretes is above F2 300. No critical decrease in the dynamic modulus of elasticity is observed, which indicates a significant freeze-thaw/frost-salt resistance of all tested highstrength concrete compositions.Conclusions. The freeze-thaw resistance studies of high-strength concretes carried out at NIIZHB named after A.A. Gvozdev yielded experimental data required to subsequently develop a standardized approach to the normalization of freeze-thaw/frost-salt resistance parameters characterizing high-strength concretes.

Study on the physical mechanical properties and freeze-thaw resistance of artificial phase change aggregates

Phase change material (PCM) is often mixed into concrete as artificial aggregate. Developing artificial phase change aggregates (APCA) with excellent freeze–thaw resistance is a key for the high-performance phase change concrete. In this paper, the APCA with controllable particle size, large apparent density, high strength, and well frost resistance was obtained by using a disc granulator. The microencapsulated phase change material (MPCM) was completely dispersed in the aggregates. The cement shell further protects the MPCM from leakage. The enthalpy, specific heat, microstructure, and product composition of APCA were measured and analyzed by differential scanning calorimeter, scanning electron microscope (SEM), and X-ray diffraction (XRD). The effects of the amount of MPCM on the strength and freeze–thaw resistance of the APCA were analyzed through single particle compressive strength test and freeze–thaw cycle test. The results indicate that the artificial aggregates with more MPCM have higher enthalpy. The MPCM can absorb the cement hydration heat, reduce the cement hydration rate, and then slow down the development of early strength of the artificial aggregates. With the increasing content of the MPCM, the apparent density and the strength of the APCA decrease, and the water absorption increases. At the same time, a large number of MPCM are added to increase the pore number of the APCA, which promotes the carbonation to develop inside the aggregates and generate a large number of calcite crystals, reducing the strength reduction caused by the increase of the pores. When the content of the MPCM is 10–30% of the mass of cement, the APCA have high freeze–thaw resistance. The maximum strength reached 66% of the 28 d strength after 200 freeze–thaw cycles, which is helpful to improve the freeze–thaw resistance of the phase change concrete.

Production and Evaluation of Synthetic Lightweight Aggregates Based on Mixture of Fluidized Bed Fly Ash and Post-Mining Residues.

This paper presents an attempt to obtain technically valuable lightweight aggregate produced from a mixture of fluidized bed fly ash and post-mining residues. The motivation to take up this study is a problem with the reasonable utilization of huge amounts of ashes produced by power plants in Poland. The ashes still produced and those stored in heaps amount to a tonnage of millions, and new ways to utilize them are desired. A real lack of mineral aggregates (non-renewable resources) demands the search for alternative materials. Using the industrial ashes as aggregates is a possible solution to the two above-mentioned problems. The aim of the study was to produce the lightweight aggregate components and to assess them in terms of their physical and mechanical properties. The components were prepared by mixing, granulation, and sintering at the temperature of over 1170 °C. Evaluation of physical parameters was based on parameters such as bulk density and water absorption. The study of mechanical properties was carried out on the basis of aggregates’ resistance to crushing. The obtained results revealed that using a mixture of the combustion and post-mining residues in the production of a lightweight aggregate is beneficial and results in the formation of a porous and durable structure. The measured resistance to the crushing of the produced aggregates varied from 5.9 MPa to 7.5 MPa. They also showed a high freeze-thaw resistance and good resistance to aggressive environments (bases, acids, salt). The registered properties indicate that the aggregates meet the basic requirements for materials used in construction and road-building. This study has a scientific and didactic value in that it describes the step-by-step process of planning and implementing the production of synthetic mineral aggregates.

Experimental Study on Freeze-Thaw Effects on Creep Characteristics of Rubber Concrete

Crumb Rubber Concrete (CRC) can exhibit high freeze-thaw resistance, but its long-term creep behavior under various freeze-thaw conditions remains unclear, which is essential for the safety of pavement engineering in the severe cold zone. In this study, the freeze-thaw effects on the creep behavior of CRC under different stress levels were systematically analyzed by testing the compressive strength, the uniaxial creep under different stress levels, and the dynamic elastic modulus. To simulate real conditions of the road environment in the cold area, the lowest temperature of −20°C, six freeze-thaw cycles of 0, 30, 60, 90, 120, and 150, and seven different stress levels of 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 of the compressive strength were employed in this study. The test results showed that the mass loss rate was 6%–11.2% and the compressive strength decreased by 6.51%–47% after 30–150 freeze-thaw cycles. When the stress level reached its critical value, the relative dynamic elastic modulus decreased with the number of freeze-thaw cycles. After 150 freeze-thaw cycles, failure did not appear when the stress level was lower than 50%, above which the creep failure was determined by the stress level and the number of the freeze-thaw cycles. Meanwhile, it was found that the cracking and interfacial debonding between the matrix and the crumb rubber particle were the main reasons for the degradation of CRC creep performance. Finally, a Weibull distribution-based empirical creep damage model was established to predict the failure of CRC, which can enhance its application to related engineering.

Particle-Bed Binding by Selective Paste Intrusion-Strength and Durability of Printed Fine-Grain Concrete Members.

The selective paste intrusion (SPI) describes a selective binding, additive manufacturing method. SPI bonds thin layers of aggregate by cement paste locally. Currently, SPI can achieve higher compressive strength, durability, and easier unpacking behavior compared to other selective binding methods suitable for the production of concrete structures. Particle-bed based methods not only achieve much higher surface resolutions than depositing (extrusion)-based additive manufacturing methods but also have no restrictions in freedom of form. However, the mechanical performance of SPI components strongly depends on the void content between the individual layers and thus the penetration behavior of the cement paste. This paper presents direction-dependent measurements of the strength and durability of SPI-printed components compared to casted specimens with the same mixing composition. The results show compressive strength values between 70 and 78 MPa after 7 d, flexural strength of 1/10 without reinforcement, a high freeze–thaw resistance, no detectable carbonation after 182 days of exposure under ambient CO2–conditions, and after 28 days under increased CO2 content of 2 vol % as well as low chloride penetration resistances. All tests showed in almost all cases no dependency on the layer orientation.

High-strength concretes based on anthropogenic raw materials for earthquake resistant high-rise construction

This work is devoted to development of optimum recipes of high-strength concretes based on filled binders with fine-milled anthropogenic mineral filler intended for earthquake resistant high-rise monolithic construction. The optimum recipes of concretes in this work have been developed on the basis of computations and experimental designing of cast concrete mixes with chemical additives and anthropogenic mineral fillers, as well as destructive inspection methods as the most precise for analysis of physicomechanical and deformation properties of concrete. The following raw materials have been used for production of high-strength concretes: natural quartz sands with the fineness modulus F.M. = 1.7-1.8; crushed limestone with the particles sizes of 5-20 mm; water reducing chemical additives and hardening retarder to control specifications of concrete mixes; plain Portland cement, grade PTs 500 D0; anthropogenic mineral additives (fillers) in the form of crushed concrete and ceramic bricks. Optimum recipes of monolithic concretes have been designed using anthropogenic raw materials including normal concrete grades with compressive strength of M30-M40 and high-strength concrete grades of M50-M80, characterized by high homogeneity of cement stone with significantly finer pores and lower shrinkage. Herewith, it has been established that fine-milled anthropogenic mineral filler in the form of crushed concrete and ceramic bricks at the ratio of 70:30, respectively, efficiently influences specifications of concrete mixes on their basis significantly increasing resistance of the mix against sedimentation and water gain. It has been established that the developed high-strength concretes based on filled binders with fine-milled anthropogenic mineral filler are characterized by high freeze–thaw resistance (from F400 to F600) and water tightness (W14 and higher), which is a solid base providing high lifecycle of such concretes.

Expansive high-performance concrete for chemical-prestress applications

By inducing a large expansion in concrete at early age, chemical-prestressing of reinforcement can be achieved. Expansions sufficient to achieve this purpose are normally obtained with a combination of admixtures (or expansive cement) and special curing methods. However, these special concrete mixtures may suffer from excessive expansion and the resulting loss of mechanical properties and durability. In this work, a combination of expansion-promoting (based on calcium sulfoaluminate, CSA) and shrinkage reducing additives (superabsorbent polymers, SAP and shrinkage-reducing admixture, SRA) is applied to produce concrete with outstanding mechanical properties and good durability. After initial underwater curing until 28 d and further drying at 70%RH, a residual expansion in unrestrained conditions of about 4000 μm/m was obtained, which enables reaching a central concrete prestress of about 2.5–3 MPa. In spite of the high residual expansion, compressive strength of about 100 MPa was obtained and the concrete had very high freeze-thaw resistance.

Development of Steel Fiber‐Reinforced Expanded‐Shale Lightweight Concrete with High Freeze‐Thaw Resistance

For the popularized structural application, steel fiber‐reinforced expanded‐shale lightweight concrete (SFRELC) with high freeze‐thaw resistance was developed. The experimental study of this paper figured out the effects of air‐entraining content, volume fraction of steel fibers, and fine aggregate type. Results showed that while the less change of mass loss rate was taken place for SFRELC after 300 freeze‐thaw cycles, the relative dynamic modulus of elasticity and the relative flexural strength presented clear trends of freeze‐thaw resistance of SFRELC. The compound effect of the air‐entraining agent and the steel fibers was found to support the SFRELC with high freeze‐thaw resistance, and the mechanisms were explored with the aid of the test results of water penetration of SFRELC. The beneficial effect was appeared from the replacement of lightweight sand with manufactured sand. Based on the test results, suggestions are given out for the optimal mix proportion of SFRELC to satisfy the durability requirement of freeze‐thaw resistance.

A novel water permeable geopolymer with high strength and high permeability coefficient derived from fly ash, slag and metakaolin

In this work, a new water permeable geopolymer with high strength and high water permeability coefficient based on fly ash-slag-metakaolin was proposed. The experimental results show that fresh geopolymer composite exhibits dry characteristic and porous structure. The void ratio is 27.6% and the permeability coefficient reaches 1.70cm/s. The compressive strength and flexural strength reach about 30MPa and 6.2MPa, respectively at 1day and reach as high as 49MPa and 11.3MPa at 28days of curing, respectively. After 100 freeze-thaw cycles, the terminal remaining mass is still larger than 80% along with internal damages and deteriorations on geopolymer paste coating. The dense microstructure of geopolymer matrix and interfacial transition zone indicates the high compressive strength, flexural strength and high freeze-thaw resistance of water permeable geopolymer.

A Preliminary Research on Alkali-Activated Slag Concrete as Tunnel Lining in Severe Frigid Regions

The main structure materials of tunnel lining are concrete and steel, and the concrete frost damage is a typical degradation phenomenon of the tunnel linings in cold regions. Alkali-activated slag concrete (ASC) has a better freeze-thaw resistance, which can be used for tunnel lining in severe frigid regions. Freeze-thaw resistance, performance mechanism of ASC and microstructure were investigated by freeze-thaw cycle, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis. The experimental results show that, ASC has excellent freeze-thaw resistance, and hydration products of ASC are mostly C-S-H, alkaline aluminosilicate. ASC has a good compact degree and uniformity of structure, and its high compressive strength also makes high freeze-thaw resistance. ASC may be selected as tunnel lining production materials in severe frigid regions because of the less reduction in the dynamic elastic modulus and mass loss of concrete.

Biofilm, ice recrystallization inhibition and freeze-thaw protection in an epiphyte community

Microbial communities found on the surface of overwintering plants may be exposed to low temperatures as well as multiple freeze-thaw events. To explore the adaptive mechanisms of these epiphytes, with the objective of identifying products for freeze-protection, enrichment libraries were made from frost-exposed leaves. Of 15 identified bacteria from 60 individual clones, approximately half had ice-association activities, with the great majority showing high freeze-thaw resistance. Isolates with ice nucleation activity and ice recrystallization inhibition activity were recovered. Of the latter, two (Erwinia billingiae J10, and Sphingobacterium kitahiroshimense Y2) showed culture and electron microscopic evidence of motility and/or biofilm production. Mass spectrometric characterization of the E. billingiae extracellular polymeric substance (EPS) identified the major proteins as 35 kDa outer membrane protein A and F, supporting its biofilm character. The addition of the EPS preparation increased the freeze-thaw survival of the more susceptible bacteria 1000-10000 times, and protection was at least partially dependent on the protein component.

Frost resistance of OPC-CSF mortars investigated by means of repeated cycle- and one cycle-freezing test

Mortars of ordinary portland cement containing 0, 5 and 10 per cent of condensed silica fume (CSF), and with water/binder ratio of 0.6 and 0.44, each non-aerated and aerated, were subjected to frost resistance investigation at 50 days age. This was done by repeated cycle freezing test (up to 150 cycles) and by one cycle freezing test method. The air void spacing factor was determined as well. The results obtained by both methods confirmed that silica fume presence improves the mortars frost resistance but the results also indicated the necessity of air entrainment if high freeze-thaw resistance of csf-containing mortars is requested or if such composites are supposed to be exposed to severe freezing conditions. Useful data (“B-point” of freezing, R W-value), as a feed-back information of the composites pore structure, are obtained after evaluation of the one cycle freezing curves.