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In order to investigate the freezing and thawing deformation, temperature field and moisture field changes under the artificial freezing conditions of typical red clay layer in Jiangxi area, this paper adopts the closed system one-way freezing and thawing test to study the remodeled red clay specimens under different freezing cold end temperature conditions, and obtain the freezing and thawing rate, thawing coefficient, freezing temperature field and moisture field changes. The test results show that: (1) the freezing and thawing displacement changes of the specimens can be divided into 7 stages during the unidirectional freezing and thawing process; the freezing and thawing coefficients decrease gradually with the decrease of the freezing cold end temperature, and the thawing coefficient is larger than the freezing rate; the lower the freezing cold end temperature, the shorter the freezing completion time, and the freezing completion time is exponentially related to the cold end temperature. (2) In the process of freezing soil samples, the lower the cold end temperature of the specimen, the higher the height of the freezing front, and the height of the freezing front is exponentially related to the freezing time. (3) The moisture field redistribution occurs in the specimen after one-way freezing and thawing in the closed system, the moisture content of the soil near the cold end of the specimen slightly increases, and the moisture content decreases by the warm end, the higher the temperature of the cold end of freezing, the greater the moisture migration, and the difference of moisture content change increases by 4. 97% when the cold end temperature -5 °C compared with -15 °C. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Acyclovir (ACV) is a promising candidate for drug repurposing because of its potential to provide an effective treatment for viral infections and non-viral diseases, such as cancer, for which limited treatment options exist. However, its poor physicochemical properties limit its application. This study aimed to formulate and evaluate an ACV-loaded red clay nanodrug delivery system exhibiting an effective cytotoxicity. The study focused on the preparation of a complex between ACV and red clay (RC) using sucrose stearate (SS) (nanocomplex F1) as an immediate-release drug-delivery system for melanoma treatment. The synthesized nanocomplex, which had nanosized dimensions, a negative zeta potential and the drug release of approximately 85% after 3 h, was found to be promising. Characterization techniques, including FT-IR, XRD and DSC-TGA, confirmed the effective encapsulation of ACV within the nanocomplex and its stability due to intercalation. Cytotoxicity experiments conducted on melanoma cancer cell lines SK-MEL-3 revealed that the ACV release from the nanocomplex formulation F1 effectively inhibited the growth of melanoma cancer cells, with an IC50 of 25 ± 0.09 µg/mL. Additionally, ACV demonstrated a significant cytotoxicity at approximately 20 µg/mL in the melanoma cancer cell line, indicating its potential repurposing for skin cancer treatment. Based on these findings, it can be suggested that the RC-SS complex could be an effective drug delivery carrier for localized cancer therapy. Furthermore, the results of an in silico study suggested the addition of chitosan to the formulation for a more effective drug delivery. Energy and interaction analyses using various modules in a material studio demonstrated the high stability of the composite comprising red clay, sucrose stearate, chitosan and ACV. Thus, it could be concluded that the utilization of the red clay-based drug delivery system is a promising strategy to improve the effectiveness of targeted cancer therapy.

In this paper, mixtures with different proportions of lime, phosphogypsum, and red clay were prepared, and the road properties and micromechanisms of lime–phosphogypsum-stabilized red clay were investigated by unconfined compressive strength test, water stability test, swelling test, shrinkage test, XRD quantitative analysis, and scanning electron microscope analysis. The results showed that the unconfined compressive strength of the mix increased and then decreased with the increase of phosphogypsum content. With the increase of age, the growth was faster in the first 14 days and basically stabilized in the last 14 days. The mixture has poor water stability, large absolute swelling rate, and low linear shrinkage. The reason for the increase of strength is that the reaction of lime, phosphogypsum, and red clay produces ettringite, and the cementing substance gels form a three-dimensional mesh skeleton structure; the excess of ettringite will cause the skeleton to expand and break, and the strength decreases.

In this study, we investigated the impact of micro- and nano-sized barium oxide addition on the radiation-shielding properties of red clay tiles mixed with waste marble and different sizes of BaO (micro- or nanoparticles) for comparative analysis. The linear attenuation coefficients (LAC) of the prepared samples were measured using an HPGe detector between 0.060 and 1.333 MeV. Moreover, a comparison was made between the experimental micro-composites and values obtained by Phy-X software. The results revealed that the red clay/waste marble tile composites doped with nano-sized BaO demonstrated superior radiation-shielding properties compared to those doped with micro-sized BaO. At 1.33 MeV, WR-20mBaO (containing 20 wt % micro-sized BaO) and WR-20nBaO (containing 20 wt % nano-sized BaO) exhibited HVL values of 4.75 cm and 4.25 cm, respectively. The lower HVL value of WR-20nBaO indicates superior radiation-shielding performance, highlighting the potential benefits of using nano-sized BaO as a radiation-shielding additive. Our findings also demonstrated that increasing the amount of BaO deposited onto red clay mixed-waste marble resulted in improved radiation-shielding properties. Our study demonstrates that adjusting the concentration of BaO is a viable strategy for enhancing the radiation attenuation properties of red clay tiles. In addition, the addition of waste marble to the tiles enhances its mechanical properties, and it is also positively recycled in community service.

In the work, an analysis of the phase formation process proceeding in a quaternary red clay--low-melting cullet--iron oxide (Fe2O3)--WAS (waste activated sludge) system in treatment at 1000oC in air has been performed. It has been established that, in sintering of the mixtures, porous ceramics consisting of a glass phase alloyed with iron ions with inclusions of cristobalite, iron-containing silicates of complex composition, α-Fe2O3, and an insignificant amount of Fe3O4 forms. The porous glass ceramics meets the compressive strength requirements imposed on building bricks. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lightweight expanded clay aggregate (LWECA) has great potential for structural applications due to its high specific compressive strength. It is synthetically produced via the thermal treatment of pellets made from raw material and bloating agent at temperatures ranging from 1,100°C to 1,300°C. In this study, aggregates are produced from red clay, fly ash, and silica sand in various proportions with various bloating agents such as coal, calcium carbonate, and bentonite. The process to produce LWECA has been optimized by varying its composition and sintering temperature. Results show that the optimum conditions for producing pellets of LWECA were achieved using red clay, fly ash, silica sand, and 20 wt% coal as bloating agents and sintering them at 1,270°C for 8 h. Concrete blocks were then made from LWECA (optimized conditions), pumice stone, and traditional coarse aggregates. Results show that the concrete blocks made from LWECA had a low water absorption coefficient, low density, and intermediate compressive strength. [ABSTRACT FROM AUTHOR]

In this work, the gamma-ray shielding parameters of red clay and boron-doped red clay with different sample thicknesses are theoretically and experimentally reported. These shielding parameters are considered at a photon energy of 0.662 MeV emitted from 137Cs. The theoretical calculations are demonstrated using the XCom software program, while a scintillation detector, NaI(TI), with an efficiency of 98% is used to attain the experimental results of the mass attenuation coefficient of the prepared samples. The acquired results show that the boron-doped clay delivers a higher mass attenuation coefficient as compared to those of pure clay. Additionally, the mass attenuation coefficient exhibits an increasing behavior with the sample thickness increment. [ABSTRACT FROM AUTHOR]

An eolian deposit section named Shaozhai, which has been developed since the Tertiary in eastern Gansu province, was analyzed for major-trace elements and Sm-Nd isotopic compositions to explore the relationship for the provenance and weathering intensity between the Tertiary red clay and Quaternary loess. The magnetostratigraphy data indicates that the basal age of the typical eolian deposits is about 5.23 Ma B.P.. We observed both similarities and obvious differences in the Tertiary red clay and Quaternary loess. Specifically, the Tertiary red clay has similar UCC-normalized major-trace element abundances and chondrite-normalized rare earth element abundances as the Quaternary loess, demonstrating that dust materials making up these sediments likely have experienced similar and numerous recycling processes prior to deposition. The Tertiary red clay has relatively high abundances of MgO, Li, Cs, Bi and low abundances of Na2O, La-Lu, Y. In comparison with the Quaternary loess, chemical weathering parameters such as Na2O/Al2O3, CIA, combined with the A-CN-K diagram suggest that the Tertiary Red clay has experienced a stronger weathering intensity. There is not much difference in the TiO2/Al2O3, SiO2/Al2O3, SiO2/TiO2, Zr/Hf, Nb/Ta, Lu/Hf, Y/Ho, Th/Nb, Hf/Nb, total rare earth elements, differentiation degree between the light and heavy rare earth element, internal differentiation degree of the light rare earth element, abnormal degree of Ce and Eu, εNd(0) of the Tertiary red clay and Quaternary loess, demonstrating a similar provenance for them. The finer grain size and stronger weathering of the Tertiary red clay may be responsible for the difference in major and trace element content for the Tertiary red clay and Quaternary loess.

The shear stress relaxation of the anchor-soil interface is the key factor causing the prestress loss of anchor rod (cable). Firstly, a device for testing the shear stress relaxation of the anchor-soil interface was developed. Secondly, a constant interface shear displacement was applied in stages to the red clay anchored element sample, and the whole process of shear stress relaxation curve of anchor-soil interface was obtained, which can be transformed to the relaxation curve at each specific loading level by using coordinate translation method. Then, the theory of fractional calculus was introduced to improve the viscous pot element, and established the red clay-anchor grout interface shear fractional M||N (composed of Maxwell body and Newton body in parallel) relaxation model. The model parameters were yielded by regression analysis of relaxation test curves under partial shear displacements, and the relationship between the model parameters and the shear displacements was also obtained by fitting. Finally, the established fractional M||N relaxation model was applied to predict another part of the relaxation curve under shear displacement level. By comparing the integer-order M||N model, the Burgers model and the five-element model (H||M||M), the results indicate that the proposed fractional M||N relaxation model not only has the advantages of simple structure and fewer parameters, but also has higher fitting and prediction accuracy.

The southern island of the Philippines is abundant in silicate minerals, including the province of Lanao del Norte. However, some of these resources in the region are untapped for use as raw materials in the production of various ceramic products for industrial, pharmaceutical, and nanotechnology applications. These could include tiles, sanitary ware, dinnerware, insulating bricks, porcelain, membranes and coatings. Some of the explored minerals are the red clay in the municipality of Linamon, diatomaceous earth in Kapatagan and black cinder in Salvador. It is the aim of this study that these minerals are evaluated in terms of their physical and chemical properties so that these will be used for optimum application. The properties that were determined were their specific gravities, raw and fired surface colors, Atterberg limits, particle size distribution, thermal properties, morphologies and mineralogical compositions. Pellets were formed for each raw material and fired at two temperature levels 1000 °C and 1200 °C to evaluate their physical properties. Linamon red clay has a 38.88% cumulative passing size of 150 µm, and the black cinder of Salvador and diatomaceous earth of Kapatagan have cumulative passing sizes of 96.53% and 60.12% at 150-micron sieve, respectively. The common mineral contents of the three samples are montmorillonite, quartz and andesine. Black cinder fired at 1200 °C has the darkest shade of red with a greasy quasi-submetallic luster. It attained the highest fusion coverage on the platform among the three materials, which makes it a potential supplement or replacement for feldspar in clay-based triaxial materials for ceramic production. The diatomaceous earth has the potential to be a secondary clay content source and a good source of flux for a certain temperature range. Both the red clay and diatomaceous earth were classified as plastic materials that are suitable for brick production, and the red clay is also feasible for pottery production. These are a few of the features of the clay minerals in the region that present suitable properties for application as raw materials in the production of ceramic tiles and hollow ceramic products.

The climatic transitions during the Miocene‐Pliocene epochs had significant impacts on the worldwide biological diversity and were associated with large turnovers of continental vegetation and fauna. Previous studies have shown that late Miocene cooling and continental aridification which was initiated 7 Ma reversed to warm conditions across the Miocene‐Pliocene Boundary ∼5.3 Ma. Here, we present detailed orbital pacing of Asian monsoon deposits to constrain further the global climate change during this period. We produce high‐resolution magnetic susceptibility records which reveal that the 1.2 Myr obliquity modulation would have been the main driving factor of the cooling and warming that occurred ∼7 and 5.3 Ma, respectively. The Tibetan rise and closures of the Panama and Indonesian seaways enhanced the impact of the 405 Kyr eccentricity cycles to an oscillatory climatic state while the Northern Hemisphere glaciations were increasing from 4 to 2.5 Ma. Plain Language Summary: For the first time, we point out eolian sediments from Chinese Loess Plateau through the Asian monsoon is primarily respond to the long‐period evolving dynamics of Earth‐Mars obliquity modulation since the late Miocene. Our study deciphers the presence of oscillatory sedimentary patterns resulting from the 1.2 Myr band were responsible for the global climate transition during the aridification and cooling at ∼7 Ma and warming at ∼5.3 Ma. Our new discovery challenges the previous hypothesis that carbon circulations involving both the marine and terrestrial carbon reservoirs were instrumental in driving late Miocene climate cooling and warming, which provide a valuable analog for the climate prediction of Pliocene‐like temperature level in the coming decades. Key Points: We investigate magnetostratigraphy and cyclostratigraphy of Chinese Loess Plateau aeolian sediments since the late MioceneThe strong imprint of 1.2 Myr obliquity was responsible for the global climate transition during ∼7 Ma cooling and 5.3 Ma warmingThe 1.2 Myr obliquity and 405 Kyr eccentricity modulations played key roles in the paleoclimate before and after 4 Ma, respectively [ABSTRACT FROM AUTHOR]

In this study, cement, zeolite powder and three industrial by-products (blast furnace slag, steel slag, and fly ash) were selected as additives to study their effects on the swelling potential of red clay with different curing ages and dosages. At the same time, the mechanism of additives reducing the swelling potential of red clay was analyzed by scanning electron microscope (SEM) and X-ray fluorescence (XRF) tests. The X-ray diffraction (XRD) test was used to detect the clay mineral content of the red clay specimens before and after the modification to determine the change in the clay mineral content of the specimens. The direct shear test was used to explore the influence of additives on the strength of red clay. The results show that with 9% cement content, the no loading swelling potential of specimens can be reduced by 82.5% under 28 days of curing, and the cohesion of the specimens can be greatly increased by 82%. However, the specimens with cement have an increase in no loading swelling potential under the condition of no curing. In contrast, when steel slag is used as an additive to modify the swelling properties of red clay, the swelling potential can be reduced without curing, but the addition of steel slag will reduce the cohesive strength of specimens. XRD testing shows that the clay mineral composition in cement-modified specimens and steel slag-modified specimens experienced a relative change, the relative content of montmorillonite and illite decreased, and the relative content of kaolinite increased. Combined with SEM and XRF test results, it is concluded that cement's reduction in the swelling potential of red clay depends on pozzolanic reaction products filling the pores in specimens and bonding clay particles, so as to reduce the permeability of red clay and increase the resistance during swelling. The addition of cement can also convert hydrophilic clay minerals into nonhydrophilic clay minerals. Compared with cement, the reduction in swelling potential caused by steel slag mainly depends on the adsorption of ions to reduce the adsorption of water molecules on the surface of clay slices. [ABSTRACT FROM AUTHOR]

As a sustainable green and efficient foundation treatment technology, reactive magnesia (MgO) and carbon dioxide (CO2) carbonation–stabilization methods are applied innovatively to improve the engineering properties of red clay. The effect of initial water content, carbonation time on the mechanical, electrical and microstructural properties of carbonated solidified MgO-mixed red clay is analyzed systematically through unconfined compressive strength–electrical resistivity synchronous test, X-ray diffraction and scanning electron microscopy test. The test results demonstrated that the stress–strain–resistivity curves of MgO carbonated red clay present good regulation, in which the stress–strain curves first increase sharply and then drop under the loading process, while the resistivity–strain curves display an opposite trend. The unconfined compressive strength (UCS) of carbonated samples, which is affected significantly by the increase in the water content and carbonation time is increasing apparently compared with no-binder parent soil. The process of carbonation exerts a perceptible effect on the relationship of UCS-E50, and the strength gain of carbonated specimens is contacted closely with the uptake amount of CO2 under the same initial parameters. Compared with carbonation duration, the initial water content has larger influence on the electrical resistivity of carbonated specimens, and the fitting equations combined with the strength and resistivity of carbonated samples were proposed. A series of mineralogical and microscopic tests, including XRD and SEM, demonstrated that nesquehonite and dypingite or hydromagnesite play an important role in improving the strength. The crystalline nesquehonite can make the structure of soil tighter because of the better cementation capacity and reduce effectively the influence of the swell of carbonation process. [ABSTRACT FROM AUTHOR]

Copyright of Science Technology & Industry is the property of Chinese Society of Technology Economics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking the red clay from Guilin, China as the object, this paper prepares red clay samples with different initial water contents, extracts the crack parameters from the images on the samples under cyclic drying and wetting through image processing, and analyzes the laws of crack development. In addition, parallel red clay samples were subject to shrinkage tests and direct shear tests under the same cyclic drying and wetting. Based on the test results, the authors discussed the laws of shrinkage deformaiton and strength change for the samples under cyclic drying and wetting, and examined the relationship between cracking, shrinkage properties, and strength detiroation of the red clay. The results show that: (1) With the growing crack rate, the volume shrinkage ratio constantly declined; the area shrinkage ratio was generally decreasing, but the decrement was not obvious in local places (in some places, the area shrinkage ratio even increased); the shrinkage coefficient generally declined, (2) Through the five dry-wet cycles, it was learned that the cohesion and internal friction angle of red clay strength can be quantified using the crack rate. This finding lays the basis for judging soil strength based on crack rate, and solving actual engineering problems with the red clay. [ABSTRACT FROM AUTHOR]

Tensile strength is an important soil parameter that affects the stability of structures built on clayey soils. This paper presents an experimental study of the change of tensile properties of red clay during wet-dry cycles. Cyclic wet-dry tests were performed on compacted red clay specimens with different initial water contents and dry densities. Direct tensile tests and Brazilian split tests were then conducted on these specimens to determine the soil strengths. The effects of initial water content, initial dry density, number of wet-dry cycles, and crack rate on the tensile properties of red clay were investigated. The results demonstrate that the tensile strength of red clay is generally 1.566 times the splitting strength. Both the tensile strength and splitting strength are negatively correlated with the initial water content but are positively correlated with the initial dry density. Because of the presence of desiccation cracks, the tensile strength goes on reducing under wet-dry cycles. The tensile strength can be expressed by a power function of the initial water content, initial dry density, and crack rate. The proposed equation is useful to evaluate the tensile strength of cracked soils subjected to wet-dry cycles. [ABSTRACT FROM AUTHOR]

An integrated rainwater management system is necessary due to the frequent occurrence of localized torrential rainfall and heat waves caused by an abnormal climate. It is necessary to develop a rainwater detention system that can implement rainwater infiltration and detention simultaneously. In this study, the safety, durability, and eco-friendliness of an eco-friendly rainwater detention system developed using an eco-friendly inorganic binder, which involves red clay, were evaluated and its economic feasibility was compared with that of the existing detention system. After 14 days, analysis of the maximum compression load and computational finite element analysis confirmed that the strength standard was satisfied and the structure was safe. No heavy metals or organic compounds were detected in the leaching test. Thus, the eco-friendly rainwater detention system is structurally safe and eco-friendly with no impact on the soil and groundwater environment, and is economically feasible because the construction cost and life cycle cost are approximately 30% and 58% lower, respectively, than those of the existing polyethylene infiltration detention tank system. These results indicate that improved safety, eco-friendliness, and economic feasibility can be achieved, compared to those of the existing system, if the eco-friendly rainwater detention system is applied in the field. [ABSTRACT FROM AUTHOR]

We conduct magnetostratigraphy and cyclostratigraphy on an eolian red clay sequence spanning 7–3.1 Ma in the eastern Chinese Loess Plateau. We pay more attention to the unconventional 173‐kyr obliquity modulated cycle which is associated with the secular frequency interference of orbital inclinations between Earth and Saturn. Similar to the 405‐kyr eccentricity cycles, the 173‐kyr obliquity band proved to be an important orbital driving component by the latest astronomical findings, and can serve as a chronometer of terrestrial air circulation reconstruction back to 7 Ma. Comparison with magneto‐cyclo‐bio‐stratigraphic timescales of another noted eolian sequence from the adjacent area, the 173‐kyr cycle is exceptionally presented as a robust recognition of the cyclical sedimentary patterns for the East Asia monsoon deposits. Plain Language Summary: In addition to astronomical rhythms associated with the amplitude modulations (AM) of Earth's precession cycles (405‐kyr long eccentricity and 100‐kyr short eccentricity), quantified the proportion of variance in macroevolutionary time series that can be also explained by AM of obliquity (most important ones are 1.2‐Myr Earth‐Mars and 173‐kyr Earth‐Saturn cycles). However, obliquity modulations have not been considered in the eolian sediments of Chinese Loess Plateau (CLP), although a number of data sets have been presented to confirm changes in the climate‐related to the obliquity modulation which is in recent astronomical solutions and geological records. Our study deciphers astrochronological cycles recorded in the eolian sediments of the eastern CLP, we point out the presence of cyclic sedimentary patterns resulting from modulated obliquity were also responsible for the alternation of decreasing and increasing phases of aridification and precipitation during the late Miocene to Pliocene. Our climate proxy demonstrates the 173‐kyr long cycle that appears in the monsoon system is a key to revealing the leading causes in long‐term monsoon variations. Our discovery improved the previous hypothesis that only the 405‐kyr long eccentricity were instrumental in driving late Miocene to Pliocene climate. Key Points: An integrated magnetostratigraphic and cyclostratigraphic study was performed from eastern Chinese Loess Plateau spanning the Miocene‐Pliocene transitionWe observed the strong imprint of the 173‐kyr cyclicity of orbital inclination rates between Earth and Saturn for the first timeAs contributions to the Asian monsoon system, obliquity and eccentricity modulations both play key roles in terrestrial paleoclimate [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose is to study the influence of water content on the shear strength of red clay under heavy metal pollution and dry-wet cycles. The red clay in Guilin is taken as the research object. Direct shear tests are carried out on red clay under different initial environments. Meantime, cadmium-contaminated red clay is artificially prepared through cadmium chloride in the laboratory. Then, with the aid of the triaxial shear test, the variation characteristics of the shear strength of the red clay with different cadmium concentrations under dry-wet cycles are studied. According to the results of the direct shear test, the relationships between water content and cohesion, and internal friction angle of red clay is explored. Also, the changes of cohesion and internal friction angle under different cadmium ion concentrations and dry-wet cycles are analyzed, and the relationship between shear strength and dry-wet cycles, as well as between peak shear strength and pollutant concentration is revealed. The results show that the cohesion and internal friction angle generally decrease with the increase of water content. Under different dry-wet cycles, the shear strength decreases with the increase of pollution concentration. The results of the triaxial test show that the lower the metal pollution on the soil is, the more obvious the effect of dry-wet cycles on the shear strength of contaminated red clay is. On the contrary, when the pollution concentration increases, the internal structure of red clay is significantly damaged, and the increase of the number of the dry-wet cycles has a less obvious effect on the enhancement of shear strength. This proves that when red clay is polluted by a low concentration of cadmium, the water evaporation cycle formed by natural rainfall can significantly improve the shear strength of red clay. This study can provide a theoretical reference for seismic disaster prevention and control of the pollution of red clay in heavy metal contaminated areas. [ABSTRACT FROM AUTHOR]

Particle size exerts a significant influence on the mechanical behavior of soil. However, insufficient research has been carried out on red clay formations, which are widespread in some Chinese provinces. Here, using unconfined compressive strength (UCS) tests, wetting–drying (WD) tests, and low-temperature nitrogen adsorption tests, we examined the relationship between the particle size and a number of mechanical and microstructural characteristics of a red clay outcropping at a construction site in China. Our results suggest that, depending on the surface area, porosity, particle size, and dry density, the failure mechanism in UCS tests will be different. That is, as the particle size increases, the failure mode of soil changes from split failure into shear failure. In addition, as the dry density increases, the UCS of the soil sample is significantly improved, and its total porosity and fractal dimension decrease. We also evaluated a dependence on particle size and the number of WD cycles on the distribution and size of cracks in WD tests. We conclude by suggesting that particle size, dry density, and WD behavior should all be taken into account in roadbed designs in red clay formations. [ABSTRACT FROM AUTHOR]

Red clay is not easy to use as a natural foundation because of its high water content, high plasticity index, large void ratio, and susceptibility to shrinkage and cracking. In this study, consolidated undrained triaxial tests were conducted to examine the mechanical properties of polypropylene fiber-reinforced red clay and to analyze the influence of the fiber content (FC), fiber length (FL), and cell pressure on its shear strength. By performing a regression analysis on the test data, a hyperbolic constitutive model that considers the influence of FC, FL, and cell pressure was established, and a method was developed to estimate the parameters of the model. The findings show that, in contrast with the nonreinforced red clay, the fiber-reinforced red clay had a stress-strain curve characterized by typical strain hardening, with the shear strength increasing with FC, FL and cell pressure. The calculated results of the model coincide with the test results well, confirming that the hyperbolic model could appropriately describe the stress-strain relationship of polypropylene fiber-reinforced red clay and have reference value for the design and construction of fiber-reinforced red clay foundations. [ABSTRACT FROM AUTHOR]

Abstract Red clay widely occupies the seafloor of pelagic environments in middle latitudes, and potentially preserves long paleoceanographic records. We conducted a rock-magnetic study of Pacific Ocean red clay to elucidate paleoenvironmental changes. Three piston cores from the western North Pacific Ocean and IODP Hole U1365A cores in the South Pacific Ocean were studied here. Principal component analyses applied to first-order reversal curve diagrams (FORC-PCA) reveals three magnetic components (endmembers EM1 through EM3) in a core of the western North Pacific. EM1, which represents the features of interacting single-domain (SD) and vortex states, is interpreted to be of terrigenous origin. EM2 and EM3 are carried by non-interacting SD grains with different coercivity distributions, which are interpreted to be of biogenic origin. The EM1 contribution suddenly increases upcore at a depth of ~ 2.7 m, which indicates increased eolian dust input. The age of this event is estimated to be around the Eocene–Oligocene (E/O) boundary. Transmission electron microscopy reveals that EM2 is dominated by magnetofossils with equant octahedral morphology, while EM3 has a higher proportion of bullet-shaped magnetofossils. An increased EM3 contribution from ~ 6.7 to 8.2 m suggests that the sediments were in the oxic–anoxic transition zone (OATZ), although the core is oxidized in its entire depth now. The chemical conditions of OATZ may have been caused by higher biogenic productivity near the equator. FORC-PCA of Hole U1365A cores identified two EMs, terrigenous (EM1) and biogenic (EM2). The coercivity distribution of the biogenic component at Hole U1365A is similar to that of the lower coercivity biogenic component in the western North Pacific. A sudden upcore terrigenous-component increase is also evident at Hole U1365A with an estimated age around the E/O boundary. The increased terrigenous component may have been caused by the gradual tectonic drift of the sites on the lee of arid continental regions in Asia and Australia, respectively. Alternatively, the eolian increase may have been coeval in the both hemispheres and associated with the global cooling at the E/O boundary.

Abstract In this study, a red ceramic was developed with the addition of sand residue from deburring and finishing processing of cast iron molds, replacing a variable fraction of the clay. The formulated masses were shaped by pressing and firing at different temperatures (850, 900 and 1000 ºC) at a heating rate of 180 ºC/h and 2-hour level. The bodies were characterized for their density prior to firing, and after firing, for mechanical strength, linear retraction, water absorption and porosity. From these results, tests were carried out with the purpose of evaluating the possible release of pollutants from the ceramic pieces produced by leaching tests according to Brazilian standards. The use of smelting sand residue, a low plasticity component, has been shown to be feasible with a few adjustments in the processing parameters and environmentally safe, as demonstrated by the experimental results.

In the present work, the prospects of using wastes of a packaging material consisting of spherical expanded polystyrene (EPS) particles for the manufacture of porous ceramics/bricks are considered. Ceramics were obtained from mixtures of red clay-grinded cullet - EPS particles. To reduce the release of toxic products of thermal destruction of EPS, two sintering modes have been developed. During sintering in the atmosphere, the two-stage temperature regime was carried out, which ensured preliminary dehydration of the clay and a quick transition to sintering at 1000°C. During sintering in conditions of oxygen deficiency in firing furnaces, the temperature gradually rises to 1000°C. At that, the sintering process is characterized by the absence of release of toxic products, and the carbonization of porous bricks. It has been established that, depending on the composition of the mixtures and the sintering conditions, it is possible to obtain durable wall ceramics with good thermal and sound insulation properties. Carbonized ceramics have enhanced strength properties due to the formation of forsterite. The presence of free carbon in the pores imparts adsorbing properties to carbonized ceramics and contributes to the appearance of electrical conductivity.

The partial replacement of conventional natural coarse aggregate (NCA) with artificial light weight aggregate (LWA) manufactured from local clay and solid waste to develop a lightweight aggregate concrete (LWAC) for the structural use was studied in this paper. Red clay and Savar clay were used individually with solid wastes like rice husk ash (RHA) and waste glass to produce LWA. The suitability of raw materials and LWA was evaluated by investigating various properties. The mechanical, thermal and durability properties of manufactured LWAC were explored. The results of physical, chemical, thermal and geotechnical properties revealed that Red clay is better than Savar clay for the preparation of LWA. All the physical and mechanical properties of LWA prepared from Red clay are suitable for the preparation of LWAC compared to Savar clay. The test results demonstrated that the concrete manufactured by replacing 30 % of NCA with LWA produced a concrete of lightweight properties. The compressive strength of LWAC for 7 and 28 days was observed as 28 and 48 MPa, respectively. The results of modulus of elasticity, splitting tensile strength, flexural deformation, and creep test of LWAC revealed that these mechanical properties meet the requirements for the structural concrete. The RCP test proves that chlorine permeability of LWAC is comparable with NCA. It was observed that the superior performance of LWAC can be achieved only when the optimized mix designed is followed strictly. The suitability of the replacement of natural aggregate by LWA may be helpful for Bangladesh due to the scarcity of natural coarse aggregate and reusability of solid waste materials., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The bearing capacity of the phyllite soil subgrade can be greatly improved by red clay, but the water stability of the modified soil is still poor. Hence, the blended soil has been found to be unsuitable for the construction of high-speed railways. This paper proposes an innovative scheme, by adding appropriate amounts of cement and red clay concurrently, to improve phyllite soil, which achieves a higher bearing capacity of the subgrade immediately after compaction, while also solving the problem of insufficient water stability. Laboratory tests of the permeability and disintegration characteristics of phyllite soils improved by cement, red clay, and both were carried out. The test results show that the permeability coefficient and maximum disintegration rate of soil can be improved effectively by using both red clay and cement. It was found that the optimal combination scheme is to add 3% cement and 40% red clay to phyllite soil by mass. Under the optimal scheme, the permeability coefficient, maximum disintegration rate, and disintegration rate of the improved soil decreased by 90.02%, 90.30%, and 99.02%, respectively, compared with the phyllite soil. The microscopic study shows that the mechanism of red clay blending with phyllite is that the finer particles of red clay infill the pores among the phyllite particles, thus reducing its permeability coefficient. The mechanism of adding cement to the blending soil mainly results from the production of hard-setting new materials and the formation of a cementation network among the soil particles, which not only increases the shear strength of the soil, but also reduces the permeability coefficient and the maximum disintegration ratio of the soil. This work makes full use of the complementary characteristics of red clay and phyllite soil and the advantages of hard-setting new materials, which will provide a new idea for soil improvement of the phyllite soil in the future.

In order to explore the test methods suitable for the red clay disintegration experiment, the advantages and disadvantages of the existing test methods were compared and analyzed. The effects of closed bubble deformation and clay minerals swelling in soils on the disintegrating property based on equilibrium theory of forces were discussed and verified by 11 groups disintegration tests of red clay under different conditions. A suitable disintegration test method was proposed from the engineering characteristics of red clay. It provides reference for the experimental study of soil disintegrating property with similar engineering properties. The results show that both the hydrostatic balance and the drying method can be used in the disintegration test in a short time (less than 3 days) for the saturated and unsaturated red clay. And a long time (more than 3 days) disintegration test can only be carried out by the later. In order to improve the accuracy of disintegrating test, it is recommended to adopt hydrostatic balance reading within 1 hour after unsaturated soil disintegrating into water. Drying readings in the whole process of saturated soil disintegration and the disintegration of unsaturated soil after 1 hour of water entry were measured by drying method. [ABSTRACT FROM AUTHOR]

Red clay has the characteristics of high water content, high porosity ratio, and complex inverse profile, which can hardly meet the requirement strength and is of most importance in the prevision of foundation or landslides which are mainly controlled by the red clay of geotechnical properties. Hence, the X-ray diffraction test, oedometer test, triaxial un-drained (CU) test, and scanning electronic microscope test are conducted to study the geotechnical properties of intact red clay. In this paper, firstly, the effect of depth on the properties of intact specimens is investigated, including mineral component, dry density, free swell ratio, water content, void ratio, and grain size distribution. Then, the characteristics of compression behavior and its development with depth are investigated. A normalization method is carried, considering the effect of structure. Secondly, CU test is performed to analyze the mechanical behavior and strength parameters of intact, reconstructed, and slurry specimens. In addition, the classification of intact red clay is used to characterize the compression behavior. The intact specimens can be classed as structural un-compacted and structural over-consolidation soil. Moreover, an attempt is made to explain the mechanism of structural strength enhancement in intact red clay, involving interlocking strength, bonding strength, and compaction strength. [ABSTRACT FROM AUTHOR]

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High-liquid limit red clay has poor engineering characteristics, namely poor water stability, low strength, and large expansion and contraction deformation. The clay may be reinforced with an F1 ionic soil stabilizer. The engineering characteristics of this reinforced clay were studied, specifically concerning its basic physical parameters, shear strength parameters, and micropore structure. The F1 ionic soil stabilizer significantly improved the water sensitivity, compaction characteristics, and shear strength of red clay. We determined that the optimal F1 ionic soil stabilizer mix was 0.5 L/m3, resulting in a reinforced clay with plastic limit increased by 45.74%, optimal moisture content increased by 12.12%, maximum dry density increased by 5.8%, liquid limit reduced by 8.4%, plasticity index reduced by 43.8%, infiltration coefficient reduced by 41.8%, cohesion increased 1.64-fold, and internal friction angle increased 1.30-fold. Freeze-thaw cycles reduced the shear strength parameters of the reinforced red clay, although even after 15 cycles, it still had 18.4% higher cohesion and 57.1% higher internal friction angle than undisturbed red clay. The F1 ionic soil stabilizer significantly reduced the pore size and area of red clay, the complex connected pore structure is adjusted to a more regular structure. The reinforced clay had 56.64% lower pore area ratio, 32.27% lower average Feret diameter, and 2.43% lower fractal dimension.

Annual coffee consumption has increased to 10 million tons. Of the coffee consumed, 65% is discarded as spent coffee grounds (SCG). However, most SCG are buried in the ground as organic waste. The more coffee consumption increases, the more land is used for disposing of spent coffee. SCG recycling has gotten considerable attention as a solution involved in these issues. The construction community has studied means and methods to recycle SCG as construction materials, such as bricks, subgrade fillers, thermal insulators, etc. This paper presents a new method, which recycles SCG as a construction material, maximally using its acidity. The SCG were hardened with natural binders (i.e., animal glue (AG) and starch (S)) and red clay (RC). The SCG mixtures were pressed with 2 MPa in a cylindrical mold and cured for 7 days. Then, the strength, durability, and pH tests were measured. The AG- and RC-treated SCG sample, which outputs 1933 kPa of strength and a 4.9 pH value, is identified as the optimal sampling method among the acid materials produced in this study. The optimal sample decreases the pH to approximately 7 of water where 68% weight of Ordinary Portland cement was soaked in.

There has been a growing environmental and economic concern about the final destination of industrial waste. This paper aims to evaluate the effect of incorporating iron ore tailing and steel slag on red ceramic bricks. The procedure for producing the fired bricks includes forming the bricks by compressing them into a mold under a specified pressure, and calcination (950 oC). In this study, the influence of high substitution (50%) of clay with IOT and BOF slag are investigated using flexural strength and scanning electron microscope (SEM). To the clay mass different proportions of residues were added, being: 25% of slag and 25% of tailing in T25.I25; 50% slag and 0% tailing at T50.I0; 0% slag and 50% tailing at T0.I50; 35% slag and 15% tailing in T35.I15; and, 15% of slag and 35% of tailing in T15.I35. Results show that IOT and BOF slag can be used together to produce fired clay brick with high level substitution, however some adjustments are required depending on the final application. This study contributes to the valorization of the waste, contributing to the planning and management of waste based on sustainability principles and aiming at reducing greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the down-dipping red clay layer seriously affects the stability of the end slope of the open-pit mine and even causes the slope deformation and instability, the method of combining numerical analysis and limit equilibrium analysis is adopted to analyze and calculate the deformation failure mode and stability of the slope for landslide disaster prevention and control of the north side of the Pingshuo east open-pit mine. Combined with the actual situation on the site, two control measures are proposed for slope toe back pressure and side cutting and load reduction. The research results show that the slope foot back pressure control measures can be used to effectively improve the stability of the side slope, increase the internal drainage space of the open-pit mine, and shorten the distance of soil discharge. The social and economic benefits are significant. At the same time, it provides a reference for safe and efficient production in the actual mining process. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Goethite in Red Clay of Middle Miocene Climate Transition (MMCT) was quantified. • Climate during MMCT in the western China Loess Plateau was relatively cold and wet. • Al substitution of goethite in the studied Red Clay sequences is relatively stable. The middle Miocene Climate Transition (MMCT, ca. 14 Ma), with a sharp drop in temperature, is a key transition period in the Earth's climatic and biotic evolution. However, our knowledge of how arid-monsoon environments were coupled during the middle Miocene Climate transition remains limited, due to the lack of robust proxies from well-dated sedimentary sequences covering the MMCT in monsoon areas. Goethite is an abundant iron oxide in soils, which is sensitive to persistent wet and cold environments. However, aluminium (Al) substitution is ubiquitous in the pedogenic process, and the Al substitution for goethite in the Red Clay sequence is unclear. In this study, we combined the rock magnetic and DRS methods to assess the Al substitution level of goethite and quantify the goethite content in the Zhuanglang (ZL) Red Clay deposits from the western Chinese Loess Plateau. Our results show that Al substitution in the ZL Red Clay sequence is relatively stable, facilitating the quantification of goethite using this approach. Goethite content displays an increasing trend from approximately 0.2% at 18 Ma to 0.5% at 14 Ma, and then gradually decreased towards the late Miocene in the ZL Red Clay deposits. The maximum goethite production at around 14 Ma indicates a cold and wet climate condition during MMCO at this location. Together with other palaeoenvironmental proxies of this sequences and other sedimentary sequences in the Tianshui Basin, we suggest that climate conditions during the MMCT in the monsoonal western CLP were relatively cold and wet, which was different from the cold and dry climate in the central Asian. Global cooling and the uplift of the Tibetan Plateau might be predominantly responsible for the cold and wet climate during the MMCT. [ABSTRACT FROM AUTHOR]

Pamukkale (Denizli) bölgesinin kuzeydoğusunda yüzeyleyen Asartepe (LE2) ve Kızılburun (LE3 ve LE4) formasyonlarından alınan üç adet kil örneğinin fiziko-kimyasal, mineralojik ve termal özelliklerini incelemek için X-ışını floresans, termal analiz, X-ışını kırınımı, Atterberg limitleri ve tane boyu analizi yöntemleri kullanılmıştır. Farklı birimlerden alınan bu killerin kimyasal ve mineralojik bileşimleri arasında çok büyük farklılıkların olmadıkları tespit edilmiştir. Mineralojik olarak, kırmızı killerin (LE2) kuvars, az oranda hematit, kil minerali olarak ise illit, az oranda kaolinit, klorit/simektit ve klorit içerdiği belirlenmiştir. Marnlı killerin ise (LE3 ve LE4) kuvars, kalsit ve piroksen içerdikleri kil minerali olarak da illit ve az klorit, kaolinit ve klorit/simektit içerdikleri tespit edilmiştir. Kimyasal bileşim açısından, kırmızı killer yüksek miktarda SiO2 (%52.0), Fe2O3 (%7.7) ve Al2O3 (%19.2) içermekte marnlı killer ise daha az oranda SiO2 (%40.1-44.5) ve Al2O3 (%12.7-14.0) ve yüksek oranda CaO (13.2-16.5) ve MgO (%3.6-3.8) içerdikleri gözlenmektedir. Tüm kil örneklerinin kızdırma kayıplarının (%14.2-17.7) yüksek olduğu belirlenmiştir. Endüstriyel uygunluk değerlendirilmeleri kırmızı killerin yaygın tuğla imalatı için yeterli özelliklere sahip olduğunu göstermektedir. Bununla birlikte, marnlı killer ise ince cidarlı delikli ürünlerin imalatı için yeterli özelliklere sahip olup, bazı değişikliklerle yaygın tuğla imalatında da kullanılabilirler.

In this paper, refractory bricks were developed by using locally obtainable materials like red clay and glass sand in Bangladesh. The Preliminary investigation was conducted by measuring the compressive strength of bricks produced by adding a range of materials with red clay in different proportions. It was found that the brick containing 30% white Portland cement and 10% glass sand with red clay (60%) demonstrated the highest compressive strength (36.20 mpa). The suitability of refractory bricks was evaluated by examining their physical and thermal properties. The evaluation of these parameters revealed that the properties are suited with refractory requirements such as low water absorption (4.58%), moderate apparent porosity (13.32%), preferable bulk density (2.64 gm/cm3 ), less linear shrinkage (3.10%), better refractoriness (1408 °C), thermal conductivity (1.3 W/m.K) and thermal shock resistance (15 cycles). The mineralogical analysis carried out by XRD exhibits the presence of Quartz and Bavenite phase. The performance evaluation shows that this brick is able to fit most of the criteria of refractory brick needed for practical purposes. Since local materials were utilized, the proposed method can be used for the manufacture of low-cost refractory brick in Bangladesh. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this study was to investigate the feasibility of using waste from the production process of the ceramic industry as feedstock for the manufacture of Portland cement. Analysis was performed in a cement industry quality control laboratory, performing chemical, physical, and mechanical tests. The results met specifications for cement production. The cement color was a limiting factor, since the consumer tends to reject cements with a slightly reddish hue. Of the tested compositions, the Red Ceramic Residue (RCR) percentage achieving favorable results for cement manufacturing without compromising color, was the 4% addition. In terms of economic and environmental viability (in Paraíba, Brazil), using this percentage to manufacture cement could represent consumption of about 48,000 tons/year of RCR, generating cost savings, and lower CO2 emissions, being an alternative for large-scale use.

In this study, cement, zeolite powder and three industrial by-products (blast furnace slag, steel slag, and fly ash) were selected as additives to study their effects on the swelling potential of red clay with different curing ages and dosages. At the same time, the mechanism of additives reducing the swelling potential of red clay was analyzed by scanning electron microscope (SEM) and X-ray fluorescence (XRF) tests. The X-ray diffraction (XRD) test was used to detect the clay mineral content of the red clay specimens before and after the modification to determine the change in the clay mineral content of the specimens. The direct shear test was used to explore the influence of additives on the strength of red clay. The results show that with 9% cement content, the no loading swelling potential of specimens can be reduced by 82.5% under 28 days of curing, and the cohesion of the specimens can be greatly increased by 82%. However, the specimens with cement have an increase in no loading swelling potential under the condition of no curing. In contrast, when steel slag is used as an additive to modify the swelling properties of red clay, the swelling potential can be reduced without curing, but the addition of steel slag will reduce the cohesive strength of specimens. XRD testing shows that the clay mineral composition in cement-modified specimens and steel slag-modified specimens experienced a relative change, the relative content of montmorillonite and illite decreased, and the relative content of kaolinite increased. Combined with SEM and XRF test results, it is concluded that cement’s reduction in the swelling potential of red clay depends on pozzolanic reaction products filling the pores in specimens and bonding clay particles, so as to reduce the permeability of red clay and increase the resistance during swelling. The addition of cement can also convert hydrophilic clay minerals into nonhydrophilic clay minerals. Compared with cement, the reduction in swelling potential caused by steel slag mainly depends on the adsorption of ions to reduce the adsorption of water molecules on the surface of clay slices.

This research conducted a triaxial test on lime-treated clay with different contents to analyze the effect of mechanical properties. Scanning electron microscope (SEM) and low-field nuclear magnetic resonance (NMR) analysis were used to analyze the effect. X-ray diffraction (XRD) was used to analyze the chemical changes of calcium oxide on red clay. The results show that with the increase of calcium oxide content, the strength increases, and it can be increased by 282% at 200 kPa confining pressure. The calcium oxide in the red clay reacted with the water in the soil to form calcium hydroxide. The alkaline environment will erode the edge of the soil particles and cause pores to become larger. SEM observed that the addition of calcium oxide caused the agglomeration of soil particles and changed the pore structure of red clay. Low-field NMR showed that calcium oxide had a significant effect on the pore structure of red clay. Calcium oxide increased the total pore volume of the soil sample. Calcium oxide had a substantial influence on the three pore distribution ranges, I (1.1–11 µm), II (15–137 µm), and III (137–512 µm). The porosity fitted with shear strength, it negatively correlated with I and III, and positively correlated with II. [ABSTRACT FROM AUTHOR]

In order to study the permeability characteristics of heavy metal ions contaminated red clay and explore the rapid detection of permeability of heavy metal contaminated red clay. Through variable-head permeability test and electrical resistivity test (different voltages and methods), the effects of Cu2+ concentration and initial water content on hydraulic conductivity characteristic and resistivity of contaminated red clay was systematically investigated. The relationship between permeability characteristic and electrical resistivity was further explored by taking Cu2+ concentration and moisture content as the intermediate variable. The obtained results indicate that the different voltage has no obvious effect on the resistivity of the samples. The four-phase electrode method is more accurate than the two-phase electrode method. With increasing Cu2+ concentrations the hydraulic conductivity of specimens increases, however the permeability coefficient of contaminated soil decreases with increasing initial water content. In the resistivity test, with increasing of Cu2+ concentrations and water content, the resistivity of samples presented a downward trend, which is decreased sharply at first and then tended to be gentle. The relationship between hydraulic conductivity and resistivity of contaminated soil showed a good fitting curve no matter in different Cu2+ concentration or in different water content, but the fitting curves of them presented opposite trend. [ABSTRACT FROM AUTHOR]

Conventionally, red clay is used for agricultural purposes in southern China. Fertilizers, especially urea, are commonly introduced into the red clay to improve the crop yields. However, due to the rapid urbanization in China, large areas of lands with red clays have been converted into sites for domestic and industrial constructions. Nevertheless, few researchers focused on the effect of urea on the strength and compressibility of red clay. In this research, the shear strength and compressibility of the red clay saturated by different concentrations of the (NH4)2CO3 solution (urea's hydrolysates) were experimentally investigated using direct shear as well as oedometer tests, respectively. It was noticed that both the shear strength and stiffness of the red clay significantly decreased after exposure to the urea solution. In addition, the micromechanisms of the strength and compressibility of the red clay treated by the (NH4)2CO3 were studied by the scanning electron microscope test and X‐ray diffraction test. Based on the test results, a new model was developed to simulate the chemomechanical behavior of saturated clayey soil by modifying the Barcelona basic model (BBM) for unsaturated soils. The proposed model introduces four additional parameters, compared to the BBM, to account for the nonlinear shear strength behavior of the red clay. This model accounts for most of the complex features related to the strength and stiffness behavior of clayey soils. The parameter calibration procedures, by using the oedometer and direct shear test results, are also presented. To validate the proposed model, experimental results from the literature are considered in which illite clay samples were either mechanically or chemically or both mechanically and chemically loaded. Part of the experimental results is used to calibrate the model parameters and the other part along with the calibrated parameters is used to verify the proposed model. A comparison between experimental data and predicted results demonstrated that the proposed model is able to capture the main features related to the chemomechanical coupling behavior of saturated soils. [ABSTRACT FROM AUTHOR]