Marl Soils Research Articles

Improvability of Quality Main Indices of a Marl Soil using Endemic Microorganisms

Improvability of Quality Main Indices of a Marl Soil using Endemic Microorganisms

Enhancing marl soil stability: nanosilica’s role in mitigating ettringite formation

Marl soil is highly prone to erosion when exposed to water flow, posing a potential threat to structural stability. The common practice of stabilizing soil involves the addition of cement and lime. However, persistent reports of severe ruptures in many stabilized soils, even after extended periods, have raised concerns. In stabilized marls, unexpected ruptures primarily result from the formation of ettringite, which gradually damages the soil structure. This article aims to assess the impact of nanosilica on the formation of ettringite and the nanostructure of calcium silicate hydrate (C-S-H) during the marl soil stabilization process with lime. To achieve this, marl soil was stabilized with varying percentages of lime and nanosilica. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were collected to observe changes in mineralogy and microstructural properties. Various geotechnical parameters, including granularity, Atterberg limits, compressive strength, and pH, were measured. The results indicate that the uniform distribution of nanosilica in marl-lime soils enhances pozzolanic activities, calcium aluminate hydrate growth (C-A-H), and the nanostructure of calcium silicate hydrate (C-S-H). According to XRD and SEM experiments, the presence of nanosilica reduces the formation of ettringite. Moreover, the compressive strength of modified samples exhibited an upward trend. In the experimental sample manipulated with 1% nanosilica combined with 6% lime, the compressive strength increased by 1.84 MPa during the initial 7 days, representing an approximately 18-fold improvement compared to the control sample.

Dynamic response, durability, and carbon footprint analysis of the marl clay treated with sodium lignosulfonate as a sustainable-environmentally friendly approach

In the current study, the marl clay was improved by different contents of sodium lignosulfonate (NLS) and cured at different times and then, all samples were subjected to Bender Element (BE), Unconfined Compressive Strength (UCS), and Brazilian Tensile Strength (BTS) tests considering two different dry condition (DC) and wet condition (WC). The durability of the samples was further controlled by a special technique, namely the soaking test. The carbon footprint analysis was undertaken for a low-volume trench project to address the sustainability benefits associated with replacing cement and lime as traditional stabilizers with NLS. The results show that the reuse of NLS as a non-traditional alternative for stabilizing marl soil can play an influential role in improving dynamic parameters as well as sustainable development. It has been observed that the CO2 emission decreases up to 5.6 and 4.4 times compared to lime and cement, respectively. Additionally, the use of NLS enhances the UCS by 249%, BTS by 208%, and small strain shear modulus by 117%. Furthermore, reducing the adverse effects of the WC on soil properties, among others, was the main finding of utilizing the NLS in marl stabilization with curing time. NLS-treated marl samples were able to preserve the integrity of their particles even after being soaked in water for a period of 3 weeks. In contrast, the particles of the untreated sample started to disintegrate within a few seconds of initiating the soaking test. Finally, possible equations correlating the dynamic and static moduli were reported in this study.

Effects of humic acid and mineral Zn fertilizer on Zn uptake and maize yield in soils formed on limestone and marl parent materials

In this study, the effects of zinc (Zn) and humic acid (HA) applications on soils (12 Aridisol soil samples) formed on limestone and marl parent materials, which are very common in Türkiye, were tested by incubation, adsorption, and greenhouse experiments. Adsorption experiments were carried out using the batch sorption technique, and the Langmuir and Freundlich isotherm parameters were calculated. In the incubation, soils were incubated with control, HA, Zn, and HA+Zn, and the DTPA-Zn was tested in five different periods (1, 7, 15, 30, and 90th days). Maize was grown for eight weeks in pots in the greenhouse. The maximum Zn adsorption for all soils ranged between 3333 and 6250 mg kg-1 in marl soils and 1042 and 5263 mg kg-1 in limestone soils, which decreased to ranges between 2631 and 5555 mg kg-1 in marl soils and 1052 and 5000 mg kg-1 in limestone soils with HA appli-cation, respectively. The desorption rate (%) of adsorbed Zn increased as the initial Zn concentration increased in all soil series formed on marl (smectite clay mineral) and lime-stone (kaolinite clay mineral) parent materials. The effects of humic acid and Zn applica-tion on the fresh and dry weights of maize were found to be statistically significant at the 5% level for marl and limestone parent material. Humic acid application increased the fresh weight of maize compared with that of the control. The highest available Zn was determined in Başkuyu series (0.79 mg kg-1) formed on marl parent material, while the lowest available Zn was obtained in Saraççeşme series (0.60 mg kg-1) formed on limestone parent material. In the greenhouse, HA increased the fresh weight of maize in soils formed on both parent materials by 0.4 and 19.6%, respectively, compared to the control. Zn fertili-zation with HA further increased the fresh and dry yields, with 12 mg kg-1 performing bet-ter. Smax (maximum Zn adsorption of the soil) parameters of soils were negatively corre-lated with EC, Pav, Kav, organic matter, silt, clay, total N, and cation exchange capacity (CEC) of the samples. Although HA alone increases the availability of Zn in plants, HA + Zn appli-cations should be applied together to obtain higher yields.

Comparative analysis of swelling mitigation in marl and clay soils: natural plant fibers (Alfa, jute, sisal) vs. polypropylene fiber with lime-pozzolana cement utilizing proctor compaction

This study offers a comparative assessment of two methodologies for mitigating soil swelling in marl and clay soils. The methods under investigation include the use of natural plant fibers (Alfa, jute, sisal) and polypropylene fibers in combination with lime-pozzolana cement. Laboratory tests, including Proctor compaction tests, and swell potential assessments, were conducted to assess the effectiveness of each method. The findings reveal that both natural plant fibers and polypropylene fibers, when combined with lime-pozzolana cement, effectively reduce soil swelling. The study underscores the promise of eco-friendly natural plant fibers and the durability of polypropylene fibers as viable solutions for soil stabilization. Furthermore, incorporating lime-pozzolana cement enhances both methods performance, providing an additional layer of soil stability. This research contributes valuable insights to geotechnical engineering projects dealing with marl and clay soils. It aids in the selection of suitable soil stabilization techniques, considering project-specific needs and sustainability concerns. Ultimately, this study advances the field of geotechnical engineering by promoting environmentally conscious and resilient solutions to address soil swelling in clay and marl soils.

Analyses of genetic diversity and population structure of endemic and endangered species Sideritis gulendamii (Lamiaceae) and implications for its conservation

Sideritis gulendamii is a perennial, endangered plant endemic to Türkiye with narrow and fragmented populations encountered in gypsum and marl soil. This species is known as mountain tea and also has a significant potential for use for medicinal and aromatic purposes. Assessing the genetic diversity of this species holds significant importance in its conservation efforts due to its specific habitat requirements, small and isolated populations, and recent threats imposed on these populations. This study determined genetic diversity at the species and population levels using the inter simple sequence repeat (ISSR) fingerprinting method on 157 individuals from seven natural populations. We observed that the species-level genetic diversity is relatively high (H = 0.189, I = 0.298), but the population-level is low (H = 0.150, I = 0.231). The greater total genetic variation within populations was determined as 76% using the analysis of molecular variance (AMOVA). The obtained value of genetic differentiation (Gst = 0.208, Φpt = 0.24) among populations is considered to be at a moderate level, whereas gene flow appears to be high (Nm = 1.899). Supportive results were reached using the STRUCTURE cluster analysis, Unweighted Pair Group Method with Arithmetic Averages (UPGMA) dendrogram, and Principal Coordinate Analysis (PCoA). The positive correlation between the matrices of genetic distance and geographic distance is determined to be statistically significant, with values of r = 0.566 and p < 0.001 in the Mantel test. Some strategies were developed using the genetic variability pattern of this endangered species for its conservation.

Impact of clay nano-material and glass fiber on the efficacy of traditional soil stabilization technique

The primary objective of this study is to evaluate the simultaneous effect of Nanoclay (NC) and Glass Fiber (GF) on improving the effectiveness of conventional soil stabilization approach. To this end, the Strength Improvement Factor (SIF) and Durability Index (DI) parameters were evaluated for marl soil stabilized with 6 % lime and varying contents of NC and GF after 7 and 28 days of curing, considering up to 8 Freeze-Thaw (F-T) cycles. The findings demonstrate that the compounds exhibit effective interlocking bonds as a result of the presence of GF and NC, as confirmed by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses. Moreover, the addition of 1 % NC and 0.75 % GF is observed to effectively improve the efficiency of lime-stabilized marl through chemical, physical and mechanical means, thus yielding higher SIF and DI values.

Stabilization/solidification of heavy metal-contaminated marl soil using a binary system of cement and fuel fly ash.

The stabilization/solidification (S/S) method is one of the most effective remediation techniques for treating contaminated soils. Several stabilizers, mostly the cementitious materials, have been used for the S/S treatment. In this paper, the feasibility of utilizing fuel fly ash (FFA) as a partial replacement of ordinary Portland cement (OPC) for the S/S treatment of marl soil contaminated with heavy metals was investigated. Two industrial waste materials, namely steel and electroplating wastes, were used to synthetically contaminate the marl soil. The stabilizers comprising of OPC and FFA were mixed with the contaminated soil at different dosages ranging from 10 to 40%, by mass, and a total of 48 S/S-treated soil mixtures were prepared. A series of experiments, including density, porosity, permeability, unconfined compressive strength (UCS), and toxicity characteristics leaching procedure (TCLP), were carried out on the soil mixtures to evaluate the efficiency of the proposed S/S treatment. Test results showed that the incorporation of FFA at higher volumes reduced the density and increased the porosity and permeability of the treated mixtures. Although FFA addition resulted in reducing the UCS values by an average of 46%, and this reduction was more significant at higher FFA percentages, the UCS values of all mixtures were more than 0.35 MPa (350 kPa), which passed the minimum requirements set by USEPA. In addition, the metal immobilization ability of the proposed treatment was confirmed by the TCLP analysis. As compared to the negative effect of the contamination of the soil by the electroplating waste, the contamination of the soil by steel waste had a higher negative effect. The results of this study would contribute in selecting an environment-friendly treatment of the contaminated soils using industrial waste materials, such as FFA, as a partial replacement of OPC. Nevertheless, the present study is an initial attempt to explore the possibility of utilizing FFA as a partial replacement of OPC in S/S treatment of marl soil contaminated with heavy metals. It is recommended to conduct another study in future including analysis of the treated soil mixtures using XRD, SEM, and FTIR techniques to better understand the stabilization/solidification mechanism and its implications on the test results.

Effect of nano-silica on engineering properties of lime-treated marl soil

One of the widely used methods for improving the engineering performance of problematic soils is in-situ or ex-situ mixing using various additives (conventionally cement and lime). In this research, the combination of nano-silica (NS) and lime additives is investigated for improving the geomechanical characteristics and engineering performance of sulfate-bearing marl soil, an expansive clayey sand soil. Due to the presence of sulfate ions, it is not appropriate to treated the soil using lime alone, and besides improving the soil’s physical condition, the NS additive can chemically prevent the formation of bulky minerals (such as ettringite) arising from the reaction of lime with soil sulfate. A comprehensive program of physical/index, compaction, wetting-induced swelling, unconfined compression and direct-shear strength and soaking-durability testing was performed on marl soil treated with 0–8 % lime and 0–1.2 % NS additives, investigating the effects of 7, 14 and 28-day curing periods. Additions of 6 % lime + 1 % NS was identified as mobilizing the highest strength properties, practically the lowest swelling potential, and achieves superior durability under the soaking condition. NS addition to the lime-treated marl soil causes secondary CSH gel formation that prevents the ettringite growth, which improves the strength and stability of the treated soil. SEM and XRD analyses confirmed these findings, with the nature and strength of the CSH phase changing with curing duration.

Dimensional Specifications and Resistance Characteristics of Olive Marl Masonry for Reinforcement and Stabilization of Excavations and Road Structures

Our study focuses on the challenges of preserving excavations and adjacent structures and stabilizing soil walls in construction projects. Neglecting appropriate protective measures can lead to settlements, instability, and alterations in the surrounding area. To address these issues, the use of retaining walls with soldier piles is recommended due to their simplicity, compatibility with different ground conditions, and adaptability to limited spaces. The manuscript presents investigations into the behavior of soldier pile walls, particularly in cohesive and marl soils. Numerical analyses and laboratory experiments were conducted to assess their performance. The research demonstrates the effectiveness of soldier pile walls in various construction operations, including highway construction, foundation excavation, and retaining walls for excavations. It also highlights their success in stabilizing slopes, embankments, underground structures, and protecting temporary and permanent retaining systems.&#x0D; Marl soil, a sedimentary rock composed of clay and calcium carbonate, presents unique challenges due to its high plasticity and semi-rigid behavior. The manuscript emphasizes the importance of understanding the behavior of piles in marl soils and improving the performance of soil nailing systems. The study examines the impact of different drilling methods on the behavior of soldier piles in marl soil, with a focus on rotary drilling with standard cement grout. The findings reveal increased tensile strength in piles installed using this method compared to percussive drilling. The research provides valuable insights for engineers and practitioners, contributing to efficient land utilization in urban areas.&#x0D; Overall, this research offers valuable knowledge for the construction industry in dealing with challenging soil conditions. It provides a foundation for developing improved design approaches for excavations and adjacent structures, particularly in cohesive and marl soils. The findings highlight the effectiveness of soldier pile walls and emphasize the need for understanding marl soil behavior to enhance the performance of soil nailing systems. Further research is encouraged to validate the results for different marl soils and explore additional strategies for improving the tensile strength and long-term behavior of piles in these conditions.

Geological and Geomechanical Characterization of Phosphate Mine Waste Rock in View of Their Potential Civil Applications: A Case Study of the Benguerir Mine Site, Morocco

Sedimentary phosphate extraction in open-pit operations generates large volumes of waste rock (WR), which are mainly overburdens and interburdens. Traditionally, the WR is mixed and stored on the surface in waste rock piles (WRPs). This paper presents a case study of the Benguerir mine site in Morocco. It investigates the potential valorization of each WR lithology based on the geological and geomechanical properties to reduce their environmental footprint and create added value to “waste.” The WR samples (soils and rocks) were collected from drill cores and mining trenches in the Benguerir mine. The geological characterization results using petrographic descriptions indicate the presence of nine phosphate layers and, in addition to the overburdens, eight interburdens. Four types of WR are identified: carbonate, siliceous, marly clay, and phosphate. The geomechanical characterization of soil-like samples showed an average plasticity index (PI) of 50% according to the methylene blue value (MBV) of 7.1, classifying them in the A3–A4 categories as plastic and clayey marl soils. The hard rock samples have excellent mechanical properties in terms of their uniaxial compressive strength (UCS), Los Angeles abrasion value (LA), and micro-Deval value (MD). The average compressive strength is 104 MPa for the flint, 35 MPa for the phosphate flint, 32 MPa for the silexite, 26 MPa for the limestone, 11 MPa for the indurated phosphate, and 8 MPa for the marly limestone. Based on the obtained results, these WRs can be considered as an excellent alternative secondary raw material for use in civil engineering applications, ceramics, and cement industries.

Marl Soil Improvement Using Recycled Concrete Aggregates From Concrete Pipes Factory

Marl Soil Improvement Using Recycled Concrete Aggregates From Concrete Pipes Factory

Effect of chitosan bio-polymer stabilization on the mechanical and dynamic characteristics of marl soils

The strength of marl soils decreases drastically in the variation of the water content. This has caused such soil to be introduced as problematic soil in geotechnical projects. In the present study, the effect of chitosan biopolymer on the static and dynamic properties of marl soil was investigated. To this end, different amounts of chitosan (up to 0.16%) were mixed with marl soil. Then samples were cured for 7, 28 and 90 days and finally subjected to 0, 1, 4 and 8Freeze-Thaw (F-T) cycles. Unconfined compressive strength (UCS), direct shear, Ultrasonic Pulse Velocity (UPV) and bender element tests were performed on the samples. The results showed that the UCS of the samples stabilized with 0.16% chitosan (as the optimal composition) increased by 227% after 7 days compared to that of unstabilized soil. Moreover, the values of cohesion and internal friction angle for the optimum mixture after 7 days of curing were equal to 38.76 kPa and 21.07°, which was much higher than 21 kPa and 18.26° related to the unstabilized marl soil. Chitosan was able to increase dynamic characteristics such as shear wave velocity and maximum shear modulus of samples by about 51 and 128% after 7 days of curing even after 8F-T cycles compared to those of unstabilized samples. Finally, chitosan exhibited that it can be a suitable alternative to traditional additives as an environmentally-friendly material, as confirmed by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses.

Mechanical characterization of marl soil treated by cement and lignosulfonate under freeze–thaw cycles: experimental studies and machine-learning modeling

Mechanical characterization of marl soil treated by cement and lignosulfonate under freeze–thaw cycles: experimental studies and machine-learning modeling

Influence of the Incorporation of Alluvial Sand on the Mechanical Behavior of Marl Soil

This study aims to evaluate the mechanical behavior of marl soil by replacing it with alluvial sand at 3, 5, and 10% by weight for a possible application in road geotechnics. After a geotechnical characterization of the materials used, the mixtures were characterized by the Atterberg limits test, the soil compressibility test, and the shear strength test. The results obtained showed that replacing a part of marl soil with alluvial sand had a positive impact on its mechanical behavior, as it improved cohesion and shear strength while significantly reducing compressibility and plasticity. These results confirm the possibility of using alluvial sand as a fine soil reinforcement or stabilization material.

Independent or Combinational Application of Sheep Manure and Litter from Indigenous Field Vegetation of Quercus sp. Influences Nutrient Uptake, Photosynthesis, Intrinsic Water Use Efficiency, and Foliar Sugar Concentrations in Olive Plants (Olea europaea L., cv. “Koroneiki”)

The recent energy crisis has increased the cost of fertilization for olive growers. This is why alternative nutrient sources, such as manures and other organic materials, could be used to sustain olive production within the framework of sustainable agriculture, by decreasing chemical fertilization inputs. A greenhouse pot experiment was established with a marl soil substrate that was modified with three amendments (sheep manure, or SM; litter from evergreen broadleaf species, or EBLS, such as Quercus sp.; their combination, i.e., SM + EBLS) and a control soil (no application of amendments) to investigate their influence on the nutrition, physiology, and leaf sugar concentrations of olive plants. Plant growth was not significantly affected by the amendments, while the lowest leaf N, K, and Zn concentrations were determined in the control soil. Significantly higher photosynthetic rate was determined in the SM + EBLS, compared to SM. Significantly higher intercellular CO2 was found in the EBLS and SM + EBLS, while significantly higher intrinsic water use efficiency (WUEi) was found in the SM + EBLS and the control. Significantly higher translocated sugar content was recorded in the SM + EBLS compared to the control. Overall, it was concluded that the optimum treatment was SM + EBLS, i.e., the combinational application of SM and EBLS. However, multi-year research under field conditions is necessary to draw more stable conclusions about the beneficial role of organic amendments on the nutrition and physiology of olive trees.

Microstructural investigation of the engineering properties of heated lime-stabilised marl soil

Marl soils, with their low bearing capacity, are widely distributed around the world. Stabilising by way of lime or cement additives is common for these soil types to enhance their performance against heat exposure. Hence, this study investigates the microstructural properties of marl soils that have been stabilised with lime additives under high temperature with special consideration of dihydroxylation temperature. In this regard, marl soils have been first stabilised with 2, 4, 6, 8 and 10 wt% lime and then heated at 100, 200, 300, 500, 700 and 900°C. Various geotechnical properties have been investigated by unconfined compression strength (UCS) test, Atterberg limits, pH variations and microstructural x-ray diffraction. The results revealed that at temperatures lower than the dihydroxylation temperature, increasing the lime percentage was accompanied by an increase in UCS. However, at higher temperatures, increasing the lime content decreased the UCS. The addition of 4% lime at ambient temperature increased the UCS to 1.7 MPa, and 3.75 MPa at 500°C.

Microstructural evaluation of the effect of diesel organic pollutant on geotechnical and geo-environmental properties of marl soil in southern Iran

Microstructural evaluation of the effect of diesel organic pollutant on geotechnical and geo-environmental properties of marl soil in southern Iran

Comparative Study between Urea and Biogas Digestate Application towards Enhancing Sustainable Fertilization Management in Olive (Olea europaea L., cv. ‘Koroneiki’) Plants

Organic fertilization is a promising strategy to decrease N mineralization rates and high N losses via leaching and denitrification, thus synchronizing N application with N uptake for crops. A 230-day experiment with olive plants was realized under greenhouse conditions to compare urea and biogas digestate (BD) application on the growth, nutrient uptake, and physiological performance of Olea europaea L. plants. The following treatments were applied: (i) UREA, (ii) UREA + DCD (nitrification inhibitor), (iii) BD, (iv) BD + DCD, (v) acidified BD, (vi) acidified BD + DCD, (vii) CONTROL (typical native Marl soil type, without fertilizer application). Under BD application, significantly higher levels of organic matter, Olsen P, and exchangeable K compared to UREA were found. Significantly lower main shoot length and total plant biomass were recorded in the CONTROL soil compared to BD. Foliar N was lower in the ACID.BD and ACID.BD + DCD treatments, while leaf P was lower in UREA. The highest PSII activity was recorded in UREA + DCD, while the highest photosynthetic rate and intercellular CO2 concentration were determined in UREA. It is expected that these data will constitute a first comparative approach between urea and BD application in olive plants, which should be carefully considered, towards boosting sustainable fertilization in the frame of circular economy strategy.

Strength and post-freeze-thaw behavior of a marl soil modified by lignosulfonate and polypropylene fiber: An environmentally friendly approach

Lignosulfonate is one of the by-products in the paper and pulp industry that is widely produced around the world and its improper disposal or storage can pose irreparable risks to human health and the environment. Sustainable reuse of this industrial waste as a stabilizing agent not only provides a novel approach in the construction industry, but also prevents the loss of natural resources. In this study, an environmentally friendly strategy involving lignosulfonate as a binder along with the polypropylene (PP) fiber as a reinforcing material was adopted to enhance the characteristics of marl soils from detrimental impacts of freeze-thaw (F-T) cycles. To this end, the pure marl specimens were improved by various contents of lignosulfonate and polypropylene fiber solely and simultaneously and cured for different time intervals. The variables assessed in this study were lignosulfonate content, polypropylene fiber content, curing period as well as the number of F-T cycles. The results showed that the greatest improvement was observed in the samples containing 1.5% lignosulfonate and 0.6% PP fibers, showing the least amplitude of fluctuations in MR reduction upon the F-T cycles. Moreover, freeze-thaw weathering transformed the stress-strain pattern of the samples from strain-softening to hardening behavior as well as increased the ductility behavior. It was observed that the simultaneous application of lignosulfonate and PP fibers led to the complete bonding of soil particles and the formation of interlocking zones around the fiber strands, leading to stronger particle bonding. The results of the Fourier transform infrared (FTIR) test also verified the formation of ionic bonds owing to the inclusion of lignosulfonate in the marl soil and the presence of lignosulfonate in the distance between the mineral layers of the soil. Overall, the reuse of lignosulfonate as a non-traditional alternative to marl soil modification can play an effective role in enhancing the durability and mechanical characteristics as well as sustainable development.