Clay Mixtures Research Articles

Effect of Fines Content on Cyclic Strength Development of Sand–Clay Mixtures under Cyclic Loading: A Process Evaluation Using Energy Methods

Effect of Fines Content on Cyclic Strength Development of Sand–Clay Mixtures under Cyclic Loading: A Process Evaluation Using Energy Methods

Synergy Between Woody Peat and Bentonite Alters Stability of Soil Organic Carbon in Coarse Soil by Enhancing Capacity for Soil Aggregation and Hydro‐Physical Properties

ABSTRACTCoarse soil has a poor structure and is susceptible to wind and water erosion, thereby making it difficult to maintain the soil organic carbon (SOC) content. Woody peat (WP) is an organic material that can increase the SOC content of the soil, while clay materials can rapidly enhance the capacity for soil aggregate formation. In order to explore the synergistic effects of WP and clay materials (bentonite and red clay) on the aggregate structure and hydro‐physical properties of coarse soil, as well as the mechanism associated with SOC mineralization (ΔSOC), we conducted an incubation study using lou soil (L0) and loessial soil (H0) with three treatments: addition of WP alone (LW, HW), mixture of WP and bentonite (LWB, HWB), and mixture of WP and red clay (LWR, HWR). The three treatments enhanced the proportion of macroaggregate (> 2 mm) and aggregate stability of the two soils, and optimized the water retention and ventilation performance. The highest aggregate stability of LWB and HWB can be attributed to the positive synergistic effect of WP and bentonite, and bentonite was more effective than red clay due to its crystal structure. The results also showed that the ΔSOC values were significantly lower under LWB and HWB than those under WP addition alone and adding the mixture of WP and red clay (p < 0.05). Moreover, partial least squares path modeling analysis showed that the hydro‐physical properties of the two improved soils inhibited SOC mineralization (p > 0.05), whereas particulate organic carbon (POC) content significantly accelerated SOC mineralization (p < 0.01). The synergistic effect of clay materials increased mineral‐associated organic carbon (MAOC), which was beneficial to maintain the long‐term effectiveness of WP. Overall, our results demonstrated that the synergistic use of WP and bentonite enhanced the aggregate stability and hydro‐physical properties of coarse soil and improved SOC storage capacity. These results provide scientific and theoretical guidance to facilitate the rapid improvement of coarse soil through engineering measures in arid and semi‐arid areas with water and fertilizer limitations.

Shear behavior at the interface of rough surfaces and cohesive soils under axial loading

Foundation elements with rough (textured) surfaces mobilize larger interface shear resistance than ones with conventional smooth or random rough surfaces when sheared against soils under monotonic loading. The overall performance of foundation elements such as piles supporting offshore wind turbines, suction caissons supporting tidal energy converters, soil nails, and soil anchors installed in cohesive soils could be enhanced through utilizing rough (textured) surfaces to resist applied static and/or cyclic loading. This paper describes the shear behavior of smooth and rough (textured) surfaces in kaolinite clay and kaolinite clay-sand mixture soils under static and cyclic axial loading. The experimental investigation presented herein consists of a series of interface shear tests performed on 3D printed rough (textured) surfaces and a 3D printed smooth reference surface utilizing the Cyclic Interface Shear Test system. The paper includes a description of the interface testing system components, cohesive soil specimens’ preparation procedure, smooth and rough (textured) surfaces details, testing procedure, and results of static and cyclic tests. Test results indicate that kaolinite clay-sand mixture soil mobilized larger static and post-cyclic interface shear resistance and volume contraction relative to kaolinite clay soil when sheared against the smooth reference surface. When tested against rough (textured) surfaces with variable asperity height, larger shear resistance was mobilized and larger soil dilation greater than that mobilized by the reference untextured surface in both soils. The results also indicate rough (textured) surfaces exhibited a prevalent frictional anisotropy increases with asperity angle and height in cohesive soils, the surfaces mobilized larger shear resistance and volume change in one direction (i.e., against the asperity right-angled side) than the other direction (i.e., along the asperity inclined side).

Enhancing bricks with titanium dioxide ore waste: Mechanical and environmental assessments

Using residues, generated in various production chains of goods and services through developing new materials for civil construction, has proven to be a promising approach to addressing environmental issues. The residue generated during titanium dioxide (TiO2) production, commonly called Unreacted Ore Waste (UOW), presents potential utilization routes in the ceramic materials production chain, thereby avoiding disposal in industrial landfills. This study aimed to investigate the effects of combining UOW with ceramic blocks for any beneficial results. The properties of ceramic blocks obtained from the mixture of clay and UOW were evaluated after adding 5 %, 10 %, 15 %, and 20 % of UOW relative to the clay’s total mass. The ceramic blocks produced were assessed for their mechanical, photocatalytic, morphological, granulometric, mineralogical, and chemical properties. The results indicated that UOW did not negatively affect the structural properties studied. The addition of UOW led to a significant 9 % increase in the self-cleaning efficacy of the ceramic block produced. The textural parameter values of the ceramic blocks decreased with UOW incorporation due to more efficient particle packing. The surface area reduced from 16.6 to 9.1 m2/g, and the pore volume decreased from 0.045 to 0.025 cm3/g for samples from 0 % to 20 % UOW, respectively. Decreased porosity values contributed to increased compressive strength, resulting in a 6.5 MPa increment. The results suggested that the addition of UOW causes an increase in Al concentrations in leachate samples, from 647.64 to 5128.92 ppb for samples from 0 % to 20 % UOW, respectively. The presence of leachate and solubilized components from UOW impaired the germination of Lactuca sativa seeds. Based on the results, although the addition of UOW resulted in toxicity from the leachate/solubilized components, it did not adversely affect any fundamental properties of the ceramic materials. It can be incorporated up to 20 % into the process, replacing traditional raw materials. This suggests promising future trends in sustainable construction, with broader applications in the development of eco-friendly building materials.

Bloating zone of artificial lightweight aggregates in triaxial whiteware compositions using ME-DOE

This study examines the characteristics of manufactured aggregates by designing an experiment using Mixture Experiments Design of Experiments (ME-DOE) for triaxial whiteware compositions and proposes the optimal mixture for manufacturing artificial lightweight aggregates. The optimal mixture designed using ME-DOE was manufactured in a pilot-scale rotary kiln. The density and water absorption rate of the manufactured aggregates were measured, and the cross-section was observed. Additionally, Mercury Intrusion Porosimetry (MIP) and 3D-CT observation were conducted to observe the pores. The samples designed using the ME-DOE were classified into five types based on the internal microstructure, which had a high correlation with the physical properties of the aggregates. The matrix composition, excluding Fe2O3 and carbon in the area where the black core was created and bloated, was formed in the area of a typical triaxial whiteware mixture. Lightweight aggregates were manufactured at the Pilot Rotary Kiln using a 50:50 mixture of feldspar and ball clay, and the manufactured lightweight aggregates met ASTM C330 standards.

A Sequential Leaching Protocol for δ11B and Trace Element Analyses of Multi‐Phase Carbonate Rocks

AbstractBoron geochemistry from biogenic carbonates offer valuable information about ocean pH and CO2 chemistry. However, application to geological carbonate deposits suffers from analytical difficulties in obtaining geochemical signals exclusively from the carbonate phase. Sequential leaching with reagents and acids has the potential to overcome such an issue. There is, however, little systematic investigation about the efficiency of sequential leaching in isolating carbonate‐associated boron from siliciclastic matrix. Here, we developed a sequential leaching protocol and applied it to methane‐derived‐authigenic‐carbonate samples. Using the leachate δ11B signatures, elemental composition, and mineral composition of residues, we show that the sequential leaching is able to improve the separation of boron from different phases. Buffered hydrogen peroxide removes organic matter and also some silicate phases resulting low δ11B values. Leaching with NH4Ac removes adsorbed boron though may also partially leach some carbonate phases. The first few leaching steps with diluted acetic acid dissolve carbonate phases. Depending on the sample type, these may also capture some remaining adsorbed boron from the preceding NH4Ac leaching. Once the adsorbed boron is completely removed, as indicated by the progressively higher δ11B values during the following acid leaching steps, representative carbonate composition can be derived. The accuracy of this protocol is demonstrated with leaching experiments using artificial deep sea coral carbonate and clay mixtures that give the representative carbonate‐associated δ11B within error of the pure coral value. Our results provide insights into characteristic signatures derived from silicates and organic matter that need to be considered in boron isotope analyses of impure marine carbonates.

Electrochemical Performance of Ti Gr. 2 as Electrodes in Contact with Saline Suspension of Clays during the Electroflotation Process

The presence of clays in copper minerals has a significant negative impact during their processing, leading to low recoveries during the flotation process. In saline environments, the presence of these clays promotes operational problems associated with salinity, leading to decreases in the copper concentrate grade, alterations in the rheology of the mineral pulp, reduction in the selectivity of copper during the flotation process, declines in the quality of clarified water, and excessive corrosion of metallic components. This study explores the electroflotation of kaolinite and montmorillonite clays in NaCl solutions using a modified Hallimond tube coupled with Ti Gr. 2 electrodes for bubble generation via water electrolysis and the corrosion analysis of these electrodes applying the superposition model. The electroflotation results show recovery of clays close to 72.68% for kaolinite, 88.44% for montmorillonite, and 67.36% for a mixture of both clays. The presence of clays helps reduce the corrosive effects of Ti Gr. 2 from 0.069 A/m2 in NaCl to 0.0073 A/m2 in NaCl with montmorillonite clay.

Composite Sand–Clay Infrastructural Soil Fills: Characteristic Consolidation and Hydraulic Properties

In the design construction of infrastructural projects comprised of geotechnical applications, including composite soil fill layers, compacted sand-clay soil fills are widely preferred as barrier layers, particularly in solid waste landfills, to minimize leakage, to prevent leachate from entering into groundwater. When bentonite clay with high water absorption capacity and low hydraulic conductivity is mixed with sand possessing relatively enhanced frictional properties, greater shear strength capacity, an effective fill material exhibiting low sensitivity to frost, and low volume change in case of wetting, drying can be obtained. On the other hand, when montmorillonite clay is loaded, due to highly critical volumetric contraction or dilation characteristics (high compressibility nature of clay), the soil fill composed of sand-clay will significantly consolidate. This situation may cause differential settlement problems of infrastructural fills employed in geotechnical applications. In this regard, the load conditions (mechanical effects) and the environmental conditions (physicochemical effects) in the field control compressibility characteristics and consolidation properties of sand-bentonite clay mixtures. This will ultimately impact the desired stability conditions of sand-clay soil layers built for constructed infrastructural fill, resulting in a deviation from anticipated performance conditions. To this end, in this study, the specimens of sand-bentonite clay mixtures prepared with different contents of sand-bentonite clay were subjected to one-dimensional consolidation tests to investigate the effect of bentonite content used in the mixture on consolidation behavior, hydraulic properties, and effect of sand amount on rate of consolidation and on resulting compressive strength behavior.

Effect of Iron Nanoparticles Prepared from Onion Extract on Cucumber Plant Growth and Production

In recent years, it has been shown that the use of chemical fertilizers negatively affects the environment and public health. Nano fertilizer have been discovered and used, and one of their many advantages is the speed and ease of obtaining them from various plant sources, which are cheap and currently available it's friendly for environment. The field experiment was carried out in the spring season of 2021 in a mixture of salty clay (cohesive soil) for the purpose of studying the effect of spraying synthetic nanoparticles used from iron oxide particles with onion plant extract at concentrations of 100, 200 and 300 parts per million on the growth and yield of cucumber (Cucumis melo var. flexuosus). The prepared nanoparticles were identified by the following assays: UV-visible spectrophotometry, XRD, FTIR, TEM, SEM and AFM. The results showed a significant effect of using Nano pesticides, especially with high concentration, in increasing average plant height, plant dry weight, leaf area and total plant yield. It was concluded from this study that the positive effect of Nano-fertilizer prepared with onion extract on plant growth, which led to an increase in cucumber productivity and the quality of its fruits, from that there is the possibility of using it as an alternative to conditional mineral fertilizers, after conducting several studies on the safety of using these plants treated with Nano-fertilizers for humans.

Neighborhood housing design using fifth generation manifesto towards nearly zero energy urban developments

Abstract Since cities are growing faster than ever before, this paper traces directly that the fifth generation of sustainable city dimensions is not a prosperous idea or a welfare mode of sustainability but a vital effective way to adapt to Climate change, provide energy production, increase carbon reduction, and enhance pedestrian-occupant thermal comfort. It is a systematic method to alleviate urban canyon temperatures, maximize shading in summer, enhance energy production, and minimize heat transfer. It shows better results than designing apartment buildings with parcel planning with its four wall surfaces absorbing heat all day long. Early from schematic design, the emphasis is based on freehand sketching, adjusting urban aspect ratio, courtyard housing closure ratio, compactness degree, and microclimatic orientation, then adding a layer of humanization with green corridors, and tree species numerically modeled based on microclimate with courtyarded passive housing clusters, moving towards detailed design execution with SCEB bearing wall construction having the majority of its mixture of clay which enhances thermal mass insulation, climate adaptation, indoor thermal comfort, and a green job opportunity. Afterward adding energy plus BIPV on the whole constructed microclimatic-based roof to twist the neighborhood into a power bank saving energy consumption, and to work as a double roof shading. It shows on the other urbanism coin side walkability, sequential visual order, urban identity, and architectural character. Numerical outdoor-indoor coupled simulations took place using Envi-met and DesignBuilder while meteorological and biometeorological parameters were measured. The new recipe ignites a sense of harmonizing results in enhancing environmental sustainability measures.

Water vapor adsorption on the mixtures of swelling and non-swelling clays

Water vapor adsorption on the mixtures of swelling and non-swelling clays

Evaluating the strength characteristics of mixtures of municipal solid waste incineration bottom ash and reddish laterite clay for sustainable construction

This study examines effects of mixing municipal solid waste incineration bottom ash (MSWI-BA) with reddish laterite clay (RLC), evaluating factors such as vertical stress, mixing ratio, curing period, and the addition of lime. A total of 153 direct shear tests were conducted to thoroughly assess the mixture's strength characteristics. Vertical stress levels of 85.5 kPa, 172.4 kPa, and 259.3 kPa were used to simulate varying stress conditions, while mixing ratios of 40 %, 80 %, 100 %, and 120 % were applied to explore potential applications of recycled MSWI-BA with clayey soils. A fast-curing approach was employed, with curing periods of 24, 48, and 72 h, to investigate the time-dependent strength development under controlled conditions. A three-way ANOVA analysis confirmed that mixing ratio, curing period, and vertical stress significantly impacted both peak and residual shear strength. The 100 % MSWI-BA mixture, with or without 1 % lime, exhibited optimal performance, providing the pronounced shear strengths and dilative behavior. The study found that MSWI-BA significantly improved shear strength ratios compared to the RLC, with improvement ratios ranging from 1.439 to 2.460 across stress levels. Additionally, upper and lower bound equations for peak and residual strength ratios were developed, providing predictive tools for mixture design. Cohesion values in the range of 8.3–128.9 kPa and friction angles from 40.6° to 44.1° were achieved, surpassing or matching those reported in similar research. The study employed Bolton's (1986) dilatancy model, finding α values between 0.61 and 0.71, comparable to those in studies of granular materials. These results highlight the effectiveness of adding MSWI-BA and lime in enhancing reddish laterite soil stabilization through both chemical and mechanical means, making it a sustainable and cost-effective approach for civil engineering projects by improving material strength, reusing local soils, recycling waste, and reducing carbon footprints.

Experimental Study of Suffusion in Sand–Clay Mixtures under Variably Saturated Conditions

Experimental Study of Suffusion in Sand–Clay Mixtures under Variably Saturated Conditions

Nature‐based shoreline protection in newly formed tidal marshes is controlled by tidal inundation and sedimentation rate

AbstractMany tidal marshes have been lost by past land use changes, but are nowadays increasingly restored and created to provide valuable ecosystem services such as nature‐based flood and erosion protection along estuarine shorelines. To be functional for flood and shoreline erosion protection, restored and created tidal marshes should develop erosion resistant sediment beds. Here, we investigated which factors drive the spatial variations in sediment strength and erosion resistance in a developing tidal marsh restoration site. Our results show that decreasing tidal inundation frequency, decreasing sedimentation rate, and better drainage led to stronger consolidation in deeper sediment layers. This consolidation resulted in greater sediment strength, quantified here by shear strength and penetration resistance. Generally, sediment strength was greater when sediment had higher bulk density, while a higher water and fine fraction (= clay and silt) content decreased sediment strength. Overall, all measurement locations were relatively erosion resistant, likely caused by the dense root network and cohesive sediment. To restore or create resilient tidal marshes for nature‐based flood and shoreline erosion protection, we should thus aim for sites with relatively low tidal inundation frequency, moderate sedimentation rates, and cohesive sediment mixtures of clay, silt, and sand, which are well drained and have potential for vegetation establishment. These conditions have a high likelihood of resulting in restored or created tidal marshes that contribute to nature‐based flood and shoreline erosion protection.

Research and analysis of the influence of recipe and technological factors on the strength of expanded clay concrete on quartz sand

The aim of the work is to study the strength and deformation properties of expanded clay concrete on cement-ash binder and to prove the technical possibility and economic feasibility of its study in structural elements of civil buildings. The five-factor plan B5 was implemented. In the matrix, each of the technological factors changed at three levels (-1; 0; +1), which made it possible to obtain quadratic mathematical models of output parameters - the bulk mass of concrete, cubic and prismatic strength of the expanded clay concrete at the age of 1 (a.s), 28, 115, 180 and 360 days, when the expanded clay concrete mixture is mobile (the constant draught of the cone is DC= 2...6 сm). Processing of experimental results to identify regularities of influence of studied factors - consumption: cement (x1); lime (х2); fly ash (х3); expanded clay gravel (х4); quartz sand (x5) on water consumption of ceramic and concrete mixtures – B, volume of inter-grain voids Vn, the density of the ceramic concrete mixture – ρo and the density of the expanded clay concrete ρ allowed to obtain with 95% reliability quadratic regression equations, taking into account only significant regression coefficients. Based on the results of experimental studies with 95% reliability quadratic regression equations of cubic and prismatic strength in the age of 1 (a.s), 28, 180* and 360* days are obtained, expanded clay concrete on CLF-binder and quartz sand with only significant regression factors. The paper examines and analyzes the influence of recipe and technological factors on the strength of expanded clay concrete on quartz sand. The invention makes it possible to use the dependence of a cubic and prism strength expanded clay concrete on quartz sand using a large component binder with a further prospect of saving cement and fillers.

Experimental Study on Static and Dynamic Characteristics of Sand–Clay Mixtures with Different Mass Ratios

The alteration of soil static and dynamic characteristics induced by clay content constitutes a crucial issue in the realm of disaster prevention and mitigation within geotechnical engineering. The static and dynamic characteristics of mixed soils with varying sand–clay contents were investigated through the design and implementation of static and dynamic triaxial tests. The relationship between clay content and soil resistance to liquefaction was investigated, with an analysis of the influence of clay content on soil strength and static liquefaction performance. Furthermore, the study examined the soil’s resistance to liquefaction under dynamic constitutive and cyclic loading conditions for soils with varying clay content. Results indicate that stress–strain curves for samples with varying clay content exhibit a consistent trend, with the lowest tangent modulus and peak strength observed in samples containing 30% clay. Increasing clay content diminishes soil’s resistance to liquefaction under static loading conditions. Higher confining pressures correspond to larger tangent moduli and peak deviating stresses in triaxial shear tests. Dynamic shear modulus decreases as clay content increases, whereas damping ratio decreases accordingly. Soil gradation significantly affects liquefaction-induced deformation, with the sample containing 30% clay experiencing the fastest increase in pore water pressure during testing failure, accompanied by fewer cyclic loading cycles until failure occurs. Improving soil gradation and adjusting the sand–clay ratio are beneficial for enhancing both soil strength and its resistance to liquefaction.

Stabilization of Krobokan Clay Soil with California Bearing Ratio (CBR) for Highway Pavement

In this research, clay soil will be stabilized in the Kerobokan Badung area by mixing the soil with various levels of lime. The problem to be solved is how much the CBR value of soil mixed with lime will increase and what is the most economical lime content associated with the minimum CBR requirements for the base soil layer. The aim is to determine the increase in CBR value from a mixture of clay with lime and to determine the most economical lime content associated with the minimum CBR requirements for the base layer of highway pavement structures. The research results show that adding lime to clay soil can increase its bearing capacity. For the standard compaction method, the CBR of the base soil which was initially 3.32% increased to 12.14, 21.86, and 26.24% for lime addition of 2.50, 5.00, and 10.00% respectively. For the modified compaction method, the CBR of the base soil which was initially 5.74% increased to 13.42, 25.69, and 38.15% for lime addition of 2.50, 5.00, and 10.00% respectively. To produce a base soil CBR of 6%, the modified compaction method requires less lime content than the standard method. The lime content required is 0.22% for modified compaction and 0.79% for standard compaction.

Influence of steel slag content on the mechanical and hydraulic properties of compacted silt-bentonite mixtures

ABSTRACT The reuse of by-products has become increasingly important as a means of minimising the consumption of natural resources and reducing waste disposal. This study examines the potential reuse of steel slag for soil stabilisation, with benefits such as conserving natural resources and mitigating the greenhouse gas emissions associated with the production of conventional stabilising agents. It focuses on evaluating the effect of pozzolanic reactions on the strength and stiffness of both loess silt and silt-bentonite mixtures. The experimental tests included the physical characterisation of granular materials, reactivity tests of the pozzolanicity of soil mixtures, compaction tests, unconfined compression tests, and hydraulic conductivity tests. The impact of the curing period was also analysed to quantify the effects of natural cementation and the development of hydrogels within soil pores on the compacted soil properties. The findings suggest that adding steel slag can significantly increase the strength and the stiffness of compacted loess silts by over 300% and 500%, respectively, after 56 days of curing, substantially reducing the hydraulic conductivity of granular materials, such as the tested silt, as hydrogels partially occupy the pores available for liquid flow. It should be noted that the chemical reactions during hydrogel formation may hinder the free expansion of clay mixtures and release Ca2+ ions, thereby counteracting the expected reduction in hydraulic conductivity when bentonite is added to compacted earthen barriers.

Shear wave implications in wetting-induced collapse of sand–clay mixtures

Shear wave implications in wetting-induced collapse of sand–clay mixtures

Fine Sediment in Mixed Sand‐Silt Environments Impacts Bedform Geometry by Altering Sediment Mobility

AbstractGeometric characteristics of subaqueous bedforms, such as height, length and leeside angle, are crucial for determining hydraulic form roughness and interpreting sedimentary records. Traditionally, bedform existence and geometry predictors are primarily based on uniform, cohesionless sediments. However, mixtures of sand, silt and clay are common in deltaic, estuarine, and lowland river environments, where bedforms are ubiquitous. Therefore, we investigate the impact of fine sand and silt in sand‐silt mixtures on bedform geometry, based on laboratory experiments conducted in a recirculating flume. We systematically varied the fraction of sand and silt for different discharges, and utilized an acoustic Doppler velocimeter to measure flow velocity profiles. The final bed geometry was captured using a line laser scanner. Our findings reveal that the response of bedforms to an altered fine sediment percentage is ambiguous, and likely depends on, among others, bimodality‐driven bed mobility and sediment cohesiveness. When fine, non‐cohesive material (fine sand or coarse silt) is mixed with the base material (medium sand), an increased dune height and length is observed, possibly caused by the hiding‐exposure effect, resulting in enhanced mobility of the coarser material. However, weakly cohesive fine silt suppresses dune height and length, possibly caused by reduced sediment mobility. Finally, in the transition from dunes to upper stage plane bed, there are indications that the bed becomes unstable and dune heights vary over time. The composition of the bed material does not significantly impact the hydraulic roughness, but mainly affects roughness via the bed morphology, especially the leeside angle.