Search

The low bearing capacity and high erosion potential of calcareous soils are major concerns in marine environments. Lime stabilization is one of the earliest and most widely used methods for improving the mechanical properties of these weak deposits. Nonetheless, the significant amount of air pollution and high energy consumption associated with lime production have led researchers to the exploration of alternative strategies, such as the utilization of supplementary materials to partially replace lime in the stabilization process. In this study, the mechanical behavior of calcareous sand specimens stabilized with 4%, 6%, and 8% of hydrated lime and zeolite-to-lime replacement proportions of 0%, 15%, 30%, 45%, 60%, and 75% was examined through a comprehensive set of unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests. The specimens were also subjected to consecutive wetting and drying cycles so that the effects of hydrated lime and zeolite proportions on the durability characteristics of treated calcareous sands were discussed. Results indicated that, in all lime contents, the UCS and constrained modulus (D) of treated samples reached their peak values when lime was substituted with zeolite at an optimum percentage of 60%. Additionally, it was observed that after four and eight wet–dry cycles, the optimum zeolite replacement ratio decreased to 45% and 30%, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were also conducted to achieve a better understanding of the microstructural changes in calcareous sands due to the stabilization with hydrated lime and zeolite. Practical Applications: The stabilization of noncohesive soils such as marine calcareous sands with lime has been a subject of interest among geotechnical engineers in recent decades. Due to the significant air pollution and high energy consumption associated with lime production, alternative strategies, such as using supplementary materials to partially replace lime, are deemed an attractive approach. In this study, the mechanical behavior of a calcareous sand (obtained from Hormuz Island as a strategic island in the Persian Gulf) stabilized with 4%, 6%, and 8% of hydrated lime and zeolite-to-lime replacement proportions of 0%, 15%, 30%, 45%, 60%, and 75% was evaluated through a series of UCS and UPV tests. Additionally, the influence of wetting and drying cycles on the strength and stiffness characteristics of treated Hormuz Island soil has also been studied; the topic which can be very significant due to the effects of waves and sea tides on the soil and structures of marine regions. Based on the experimental results, replacing lime with zeolite could efficiently improve the mechanical behavior of calcareous sand specimens, specifically when subjected to consecutive wet–dry cycles. In particular, 45% and 30% of zeolite replacement were shown to be the best substitutes for lime after four and eight cycles of wetting and drying, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

Several methods have been used over time to improve the mechanical properties of fine-grained soils. One of the recently introduced materials for soil stabilization is incinerated sewage sludge ash (ISSA). This material is a by-product of the wastewater treatment process that is usually disposed of during the treatment cycle. This paper investigated the effects of adding the optimum amount of ISSA and a mixture of ISSA with hydrated lime (IL) on the mechanical properties of dispersive fine-grained soil. The effects of curing time on the UCS was also evaluated. The Mohr-Coulomb failure envelope parameters of the mixtures were subsequently estimated based on the performed test results using the Consoli et al (J Mater Civ Eng 27(5):04014174, 2015) method which eliminates the need to perform triaxial tests. The results indicated that ISSA and IL can improve the mechanical characteristics of the dispersive soil effectively and that curing time was substantial for better performance of the treated soil. Finally, the application of the Consoli and others method to predict the failure envelope parameters of the treated soil was evaluated using triaxial tests. The comparison of the results proved the suitability of the proposed method to estimate the failure envelope parameters of the ISSA and IL-treated dispersive soil. [ABSTRACT FROM AUTHOR]

Cracks in concrete, including recycled aggregate concrete (RAC), lead to durability issues from substance penetration. This study introduces microbial precipitation for crack healing in RAC. It substitutes 50% and 100% of natural coarse aggregate with recycled coarse aggregate and replaces cement with blends of hydrated lime and brick powder. Self-healing effectiveness is assessed through compressive strength, RCPT, UPV, and microscopic analysis. Results show complete healing of 0.58 mm cracks over 56 days, with compressive strength regain ranging from 94% to 56%. RCPT variation ratios range from 142% to 173%. Microstructural analysis through FESEM, EDS, and XRD reveals microbial precipitate properties. FTIR and TGA analyses explore CaCO3 through infrared absorbance and mass variation with temperature. The study suggests that microbial-induced self-healing improves strength and durability in recycled aggregate concrete. [ABSTRACT FROM AUTHOR]

Moisture damage (MD) in bituminous mixtures occurs due to the loss of cohesion in the bitumen or adhesion between the binder and aggregates. The existence of moisture may influence the bonding between aggregates and bitumen, which may affect the moisture susceptibility of the bituminous mix. Therefore, there is a need to understand the bonding-debonding properties and the moisture susceptibility of binders and mixes, at the material selection stage. Surface free energy (SFE) method is one of the proven techniques to quantify the moisture susceptibility of bituminous mixtures, by using contact angle (CA) determination of the component materials of the mix. This study aimed to evaluate the effect of hydrated lime (HL) on the moisture susceptibility of bituminous mixtures, with control (VG30) bitumen and pyro-oil modified bitumen (POMB) having different percentages of pyro oil, using the SFE approach. Also, the study compared the SFE characteristics of VG30 and POMB with and without the optimum content of HL. POMB binders were prepared by the addition of high-density polyethylene (HDPE) pyro oil in percentages of 1, 3, and 5% in a control bitumen. HL was added as 20%, 25%, and 30% by weight of bitumen in VG30 and POMB bitumen. The aggregates used in the study were limestone, basalt, gravel, and their SFE components were directly considered from the literature. The sessile drop method was used to measure the CA of bitumen and, in turn, determine the various SFE parameters using Van Oss–Chaudhury–Good theory. The moisture susceptibility of mixtures with and without HL was evaluated and compared. From the results, the MD resistance of the bituminous mixtures with modified and unmodified bitumen was found to be increased after the optimum of HL, depending upon the type of aggregates used. Basalt has a 27.41%, 23.38%, and 10.48% greater energy ratio (ER) with POMB1/25, POMB3/25, and POMB5/30, respectively, than VG30/30, the highest ER in modified base bitumen. This indicates that HDPE pyro-oil treatment improves MD resistance for basalt. Whereas for limestone and gravel, VG30/30 gives a maximum value of ER as compared to any other combination of HL modified POMB. The ER values would assist highway agencies in selecting the most compatible binder–aggregate combinations. [ABSTRACT FROM AUTHOR]

If asphalt pavements are exposed to cold weather conditions and high humidity for long periods of time, cracking of the pavement is an inevitable consequence. In such cases, it would be a good decision to focus on the filler material, which plays an important role in the performance variation in the hot asphalt mixtures used in the pavement. Although the use of hydrated lime as a filler material in hot asphalt mixtures is a common method frequently recommended to eliminate the adverse effects of low temperature and to keep moisture sensitivity under control in asphalt pavements, the sensitivity of the quantities of the material cannot be ignored. Therefore, in this study, an amount of filler in the mixture was replaced with hydrated lime (HL) filler additive at different rates of 0%, 1%, 2%, 3% and 4%. These asphalt briquettes, designed according to the Marshall method, have optimum asphalt contents for samples with specified HL content. In this study, where the temperature effect was examined at five different levels of −10 °C, −5 °C, 0 °C, 5 °C and 25 °C, the samples were produced in two different groups, conditioned and unconditioned, in order to examine the effect of water. The indirect tensile strength (ITS) test was applied on the produced samples. Experimental study showed that HL additive strengthened the material at low temperatures and made it more resistant to cold weather conditions and humidity. In the second part of the study, two different prediction models with varying configurations were introduced using nonlinear regression and feed-forward neural networks (FFNNs) and the best prediction performance among these was investigated. Examination of the performance measures of the prediction models indicated that ITS can be accurately predicted using both methods. As a result of comparing the developed models with the experimental data, the model provides significant contributions to the evaluation of the relationship between the ITS values obtained with the specified conditioning, temperature changes and HL contents. [ABSTRACT FROM AUTHOR]

Abstract Expansive soils pose significant challenges to road construction globally due to their tendency to expand and contract with changes in moisture content, leading to pavement failure. In the construction industry, finding an economical and cost-effective alternative to conventional road construction materials is crucial. The use of a natural cinder ash and hydrated lime mixture as reinforcement has proven to be effective in addressing this issue. Cinder ash, a readily available waste material in countries like Ethiopia, is adaptable and water-resistant, making it an ideal choice for reinforcing expansive soil. This article investigates the strength performance of a cinder ash and hydrated lime mixture as a reinforcement material for expansive soil. The study involves mixing 0%, 20%, 25%, 30%, and 35% of cinder ash with soil stabilized with 2–5% hydrated lime. Expansive soil samples are prepared according to the ASSHTO & ASTM method and tested for compressive strength, California bearing ratio, bulk density, and water absorption. The findings reveal a 448.62%, and 374% increase in compressive strength and California Bearing Ratio respectively for the specimen containing 5% hydrated lime and 35% cinder ash, cured for 28 days. The water absorption is minimized at 15.23% for the 5% hydrated lime and 35% cinder ash mixture; while the maximum density of the soil is observed at 1.774 kg/m3 for the optimal combination of 5% hydrated lime and 35% cinder ash mix. The study suggests that using 5% hydrated lime and 35% cinder ash content for the stabilization of expansive soil significantly enhances the strength characteristics of compressed stabilized soil.

Abstract Aging of binders is a complex phenomenon which reduces the longevity of flexible pavements. Aging involves change in physical, chemical, and morphological properties of binder which makes the binder brittle and highly susceptible to fatigue and thermal cracking. Antiaging additives enhance the service life of flexible pavements by reducing the impact of aging on the performance of binders. An iterative approach is essential to identify the optimal dosage of antiaging additive necessary to counteract the aging effects on binder. The present study aims to evaluate the mixing conditions for uniform dispersion of carbon black and hydrated lime within the binder matrix and thereby evaluate the impact of incorporating these antiaging additives on the conventional properties of binder. For this purpose, varying proportions of carbon black and hydrated lime are added to VG 30 binder and is subjected to softening point, ductility, and penetration tests. The optimal dosage of carbon black and hydrated lime is found to be 6 and 12% respectively based on their significant effects on the conventional properties of the binder. An optimal mixing duration of 60 and 75 min ensures uniform dispersion of carbon black and hydrated lime within the binder matrix at a mixing temperature of 120 °C and a speed of 1000 rpm thereby producing a homogenous binder mastic. Incorporation of antiaging additives up to the optimal dosage enhances the softening point whereas decreases the penetration and ductility of binder. The increase in softening point of binder with incorporation of carbon black and hydrated lime signifies enhanced resistance to rutting and permanent deformation of binder, whereas the reduction in ductility and penetration of binder with incorporation of carbon black and hydrated lime signifies the reduced susceptibility of binder to environmental factors such as temperature fluctuations, UV radiation, and oxidation. The surface texture of the additive influences the ability of binder adsorption, which subsequently affects the rheological properties of binder mastics. Significant improvement in conventional properties of binder with incorporation of carbon black and hydrated lime paves a viable and cost-effective solution for engineering application as it has a subsequent effect on the rheological properties of binder.

Introduction. Creation of waste-free technologies for production of low-energy building materials and products involving recycling of secondary raw materials is one of the priority areas of economic development in most countries. In this regard, the urgent task is to develop competitive binders based on phosphogypsum with the addition of hydrated lime by designing rational compositions of phosphogypsum-lime compositions hardening by mixed type.Materials and methods. Waste phosphogypsum from Titanium Investments LLC, Armyansk, was used as a secondary sulfate-containing raw material. Hydrated lime for research was obtained by slaking lump lime produced in shaft furnaces of the lime workshop of Crimean Soda Plant JSC, Krasnoperekopsk. Analysis of the mineralogical composition of phosphogypsum and artificial stone based on it was carried out using synchronous TG-DTA/DSC thermal analysis on an STA 8000 analyzer (Perkin Elmer). The dispersed composition of phosphogypsum and hydrated lime was determined by laser diffraction using a Partica LA-960 laser particle size analyzer (Horiba). The determination of the mechanical characteristics of the prototypes was carried out on the basis of the MCC8 control console (Controls).Results. The results of the development of compositions based on phosphogypsum-lime compositions showed that after forced carbonization of these compositions for 180 minutes in an air-gas environment with a 50 % CO2 concentration, it is possible to obtain a water-resistant stone material (Kr 0.78–0.8) with strength at compression 28–32 MPa, average density 1,750–1,780 kg/m3 and water absorption by mass and volume of 11–15 and 19–26 %, respectively.Conclusions. Probably, additional optimization of the conditions of obtaining samples (pressure, water content of the mixture, introduction of filler), the regime of forced carbonate hardening (hardening time, CO2 concentration) will further improve the studied properties of the resulting stone material. The obtained experimental data suggest that, based on the proposed binder, it is possible to produce a certain range of small-piece wall products, taking into account additional scientific research in this area.

Materials for the conservation of cultural heritage must meet specific demands, such as high durability, service life, and compatibility with other materials used in the original building structures. Due to their low permeability to water and water vapor and their high rigidity, the use of Portland cement (PC) mortars, despite their high mechanical resistance and durability, does not represent an appropriate solution for the repair of historic masonry and structures. Their incompatibility with the original materials used in the past, often on a lime basis, is therefore a serious deficiency for their application. On the other hand, lime-based mortars, compared to PC-based materials, are more susceptible to mechanical stress, but they possess high porosity, a high water vapor transmission rate, and moderate liquid water transport. This study aims at the development of two types of lime-based mortars, calcium lime (CL) and hydraulic lime (HL). The modification of mortars was conducted with a carbon-based nanoadditive and graphene nanoplatelets (GNs) in three dosages: 0.1%, 0.3%, and 0.5% of the binder weight. The enhancement of CL mortars by GNs greatly increased mechanical strength and affected heat transport characteristics, while other characteristics such as porosity, water absorption, and drying rate remained almost similar. The application of GNs to HL not only enhanced the strength of mortars but also decreased their porosity, influenced pore size distribution, and other dependent characteristics. It can be concluded that the use of graphene nanoplatelets as an additive of lime-based composites can be considered a promising method to reinforce and functionalize these composite materials. The improved mechanical resistance while maintaining other properties may be favorable in view of the increasing requirements of building materials and may prolong the life span of building constructions. [ABSTRACT FROM AUTHOR]

Currently, humanity is facing two existential problems: the constant reduction of fossil fuel supplies, primarily crude oil, and global climate change, which is a direct consequence of the increasing use of fossil fuels both in industry and in the transport sector [1, 2]. One of the possible solutions for these problems are biofuels, fuels obtained from renewable raw materials, as it is biodiesel [2], which attracted attention due to characteristics such as high degradability, non-toxicity and low emission of carbon monoxide, particulate matter and unburned hydrocarbons, as well as the possibility of being used either in a mixture with fossil with diesel or independently as 100% biodiesel fuel [3, 4, 5, 6]. Heterogeneous catalysts in transesterification processes, i.e. biodiesel production, have been an area of significant and extensive research for many years. It is noticeable that there are significantly fewer works in which the application of Ca(OH)2, was investigated, and the published works show conflicting results, both in terms of its catalytic activity and in terms of the achieved yield of fatty acid methyl esters (FAME). The main goal of this work was to analyze the physico-chemical, chemical, mineralogical, morphological and surface characteristics of hydrated lime produced by Stamal Ltd. Kreševo, with the aim of examining the possibility of its application as a catalyst in the process of transesterification of vegetable oils. The obtained results unequivocally show that by using this hydrated lime as a catalyst in the transesterification process of rapeseed oil, it is possible to achieve a yield of methyl esters that meets the minimum limit of 96.5% prescribed by the European standard for biodiesel, EN 14214. [ABSTRACT FROM AUTHOR]

Copyright of Roads & Bridges / Drogi i Mosty is the property of Road & Bridge Research Institute 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.)

Soils with a significant proportion of clay or silt tend to have poor geotechnical characteristics (such as volumetric change and low strength) when exposed to varying moisture contents. The chemical stabilizers currently used are costly and have negative effects on the environment. Arkansas, in the United States, is the leading producer of rice in the country. During rice production, ~20% of the harvested grain consists of rice husk (RH). The rice milling process produces ash with a considerable amount of silicate. Research is being conducted to address the environmental concerns associated with its disposal in Arkansas, as there is growing interest in using rice husk ash (RHA) as a stabilizing additive for problematic soils. For RHA to be effective, an activator such as lime may be needed. The present study focuses on investigating the effectiveness of RHA in stabilizing substandard soils, as no prior study has used RHA as a stabilizing agent in the United States. Additionally, the research aims to determine the optimal proportions of RHA, hydrated lime (HL), or a combination of both. The study employs varying percentages of RHA (3%, 6%, and 9%) and HL (1%, 3%, and 5%) in a unary system. In the binary system, 3%, 4%, and 5% of RHA are combined with 1% HL. The study includes a range of routine tests, such as assessments of Atterberg limits, modified proctor compaction, pH levels, California bearing ratio (CBR), unconfined compressive strength (UCS), and free swell (FS). Furthermore, results from scanning electron microscopy (SEM) coupled with X‐ray diffractometer analyses demonstrated significant improvements in UCS and CBR values for the treated soils, indicating enhanced strength and stability. Moreover, the FS test reveals a reduction in swelling characteristics for the stabilized soils. It was found the optimal dosages of RHA and HL were 6% and 3%, respectively. Notably, when RHA and HL were combined, a blend of these two stabilizing agents exhibited the most promising results in terms of improving the swelling. The optimum percentage of the combined stabilizing agents was 4% RHA + 1% HL. The findings of this proof‐of‐concept research hold substantial potential for the construction industry in Arkansas, offering cost‐effective alternatives to conventional soil stabilization methods while promoting the sustainable and environmentally conscious use of RHA. [ABSTRACT FROM AUTHOR]

Aging of binders is a complex phenomenon which reduces the longevity of flexible pavements. Aging involves change in physical, chemical, and morphological properties of binder which makes the binder brittle and highly susceptible to fatigue and thermal cracking. Antiaging additives enhance the service life of flexible pavements by reducing the impact of aging on the performance of binders. An iterative approach is essential to identify the optimal dosage of antiaging additive necessary to counteract the aging effects on binder. The present study aims to evaluate the mixing conditions for uniform dispersion of carbon black and hydrated lime within the binder matrix and thereby evaluate the impact of incorporating these antiaging additives on the conventional properties of binder. For this purpose, varying proportions of carbon black and hydrated lime are added to VG 30 binder and is subjected to softening point, ductility, and penetration tests. The optimal dosage of carbon black and hydrated lime is found to be 6 and 12% respectively based on their significant effects on the conventional properties of the binder. An optimal mixing duration of 60 and 75 min ensures uniform dispersion of carbon black and hydrated lime within the binder matrix at a mixing temperature of 120 °C and a speed of 1000 rpm thereby producing a homogenous binder mastic. Incorporation of antiaging additives up to the optimal dosage enhances the softening point whereas decreases the penetration and ductility of binder. The increase in softening point of binder with incorporation of carbon black and hydrated lime signifies enhanced resistance to rutting and permanent deformation of binder, whereas the reduction in ductility and penetration of binder with incorporation of carbon black and hydrated lime signifies the reduced susceptibility of binder to environmental factors such as temperature fluctuations, UV radiation, and oxidation. The surface texture of the additive influences the ability of binder adsorption, which subsequently affects the rheological properties of binder mastics. Significant improvement in conventional properties of binder with incorporation of carbon black and hydrated lime paves a viable and cost-effective solution for engineering application as it has a subsequent effect on the rheological properties of binder. [ABSTRACT FROM AUTHOR]

This paper proposes a mechanical dispersion method of hydrated lime in a vibrating activator equipped with special blades that operate in a resonant mode. It has been found that during the vibro-activation process, hydrated lime consistently passes through proportionately increasing stages of dynamic viscosity, slowing its growth and ceasing dispersion. A new vibration method for determining the viscosity of the hydrated lime-water system has been developed. The effect of vibration treatment on changes in the dispersion of calcium hydroxide was studied. It has been found that vibration-treated lime, compared to conventional hydrated lime, has new properties: the ability to form durable coatings due to accelerated carbonization. [ABSTRACT FROM AUTHOR]

The construction sector is among the most polluting industries globally, accounting for approximately 37.5% of the European Union's total waste generation in 2020. Therefore, it is imperative to develop strategies to enhance the sustainability of this sector. This paper proposes a multiscale COMSOL Multiphysics numerical model for an ex situ mineral carbonation process of hydrated lime. The carbonation process is characterized at both the micro- and macroscale levels, encompassing interactions within and between the particles. This model incorporates both reaction and diffusion phenomena, considering the effects of porosity and liquid-water saturation parameters. Generally, liquid-water saturation enhances the reaction kinetics but not CO2 diffusion, while porosity improves CO2 diffusion throughout the granular bed. The model has been experimentally validated, showing promising results by accurately characterizing carbonation tendencies and the influence of the CO2 flow rate and the initial water-to-solid ratio on the carbonation process. The proposed mathematical model facilitates the study of various parameters, including particle radius, reactor geometry, and material porosity. This analysis is valuable for both current and future projects, as it aims to identify the most profitable configurations for the hydrated lime carbonation process. [ABSTRACT FROM AUTHOR]

Thermoactivated recycled cement (RC) is a growing area of research and development in the cement industry. The approach represents a reversible process of cement hydration in which dehydrated compounds with similar characteristics to cement are obtained by means of thermal activation. To avoid CO2 emissions during the production of such RC, this study assesses the possibility of replacing ordinary Portland cement (OPC) with hardened cement powder (HCP) prepared with different proportions of hydrated lime (HL), relying on a second pozzolanic reaction, and compares it with RC mortars. Due to the thermal activation of HCP, the compressive strength increases by 11.5%. The addition of 8% HL produced an important increase in strength from 28 days to 90 days by 12.8%, although without surpassing the strength values of mortar produced only with HCP or with RC. The compressive strength results suggest the existence of a secondary pozzolanic reaction when using HCP from a cement paste source, but such a pozzolanic reaction was fully perceived in XRD patterns when using concrete as parent material, unlike cement paste, possibly due to large crystalline sand peaks that could have hindered the effective identification of smaller crystalline peaks. [ABSTRACT FROM AUTHOR]

Due to its acidic nature and high fluoride concentration, hydrated lime (Ca(OH)2) is commonly used for neutralization and fluoride control in semiconductor wastewater treatment. This study investigated the efficacy of treating high fluoride-containing wastewater using hydrated lime derived from oyster shells as an alternative to limestone. Overall, the characteristics of removing pollutants in acidic wastewater using shell-based hydrated lime showed similar patterns to hydrated lime from limestone. The treatment efficiency was 50% or less under theoretical Ca/F molar ratio (=0.5) conditions for the formation of fluorite (CaF2), while the fluorine removal rate reached 99% under somewhat higher Ca/F conditions due to the influence of ionic components in the wastewater. Interestingly, chloride content did not increase even in the initial reaction stages, in contrast to our concerns about oyster shells generally containing salt to a certain extent due to their growth in seawater; instead, the chloride concentration decreased over time, similar to nitrate (NO3−). In controlling fluoride in wastewater, surpassing the theoretical Ca/F molar ratio, particularly considering the presence of other anionic species such as SO4²− and PO4³−, the optimal Ca/F ratio for fluoride removal was found to be 1.59. This value is approximately 16% lower than the calculated value (Ca/F = 1.85) when accounting for other anions. X-ray diffraction results confirmed the presence of CaSO4, Ca3(PO4)2, and CaF2 in the precipitate recovered after the reaction, indicating the effective removal of ionic contaminants. This observation suggests that oyster shell-derived hydrated lime could serve as a viable calcium resource for treating acidic wastewater and represents a potential alternative to traditional limestone-based methods. [ABSTRACT FROM AUTHOR]

The filler in the asphalt mixture is essential since it plays a significant role in toughening and stiffening the asphalt. Changes in filler type can lead the asphalt mixtures to perform satisfactorily during their design life or degrade rapidly when traffic and environmental effects are considered. This study aims to assess the impact of filler types such as limestone dust (LS) and hydrated lime (HL) on Marshall characteristics and moisture damage in asphalt mixtures. Three different percentages of HL were employed in this study to partially replace the LS mineral filler: 1.5, 2.0, and 2.5% by aggregate weight. Furthermore, a control mixture was created with 7% LS by overall aggregate weight for the wearing course layer. The Marshall method was used to obtain the optimal asphalt content and the asphalt mixes' volumetric properties. The optimum asphalt content was used to prepare the asphalt concrete mixes, which were then tested for moisture damage resistance using the indirect tensile strength (ITS) and the index of retained strength (IRS). The findings demonstrate that resistance to moisture damage can be significantly enhanced by partially substituting HL for the LS filler. This was verified by the fact that the optimum increase in the tensile strength ratio (TSR) was 7.29% at 2.5% of HL, and at the same HL percent, the greatest rise in the IRS was 9.81% compared with the control mix.

In the gas treatment center in smelters, hydrogen fluoride (HF) is separated from the outlet gases of electrolysis cells, which are used to produce aluminum from alumina. However, SO2 largely remains in the effluent gas. Another method has to be developed to separate this gas which is harmful to the environment. In this study, semi-dry desulfurization of a SO2 containing gas was performed at low SO2 concentrations using hydrated lime [Ca(OH)2] as a catalytic desulfurizer under specific humidity conditions. The low reaction temperature of 100 °C and minimal use of the Ca-based desulfurizer under 17 % relative humidity achieved more than 95 % removal of SO2. The morphological changes and presence of sulfur in different lime samples were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Brunauer–Emmett–Teller (BET) analysis showed changes in the surface properties of hydrated lime after desulfurization. X-ray photoelectron spectroscopy (XPS) analysis provided the phase and composition identification of the sulfur species on hydrated lime and the CaSO3/CaSO4 product ratio. Based on the experimental results, the optimum catalyst surface area with a specific particle size is critical to the effective conversion of Ca(OH)2 into CaSO3 and CaSO4. The practicality of a Ca-based desulfurizer and its ability to convert into the required product may be the key to reducing the overall cost of desulfurization in aluminum industry.

This study investigates the efficacy of sodium alginate (SA), xanthan gum (XG), guar gum (GG) and chitosan (CS) — each applied at five different solid biopolymer-to-water mass ratios (or dosages) and cured for 7 d and 28 d — on the unconfined compressive strength (UCS) performance of a high plasticity clayey soil. Moreover, on identifying the optimum biopolymer-treatment scenarios, their performance was compared against conventional stabilization using hydrated lime. For a given curing time, the UCS for all biopolymers followed a rise–fall trend with increasing biopolymer dosage, peaking at an optimum dosage and then subsequently decreasing, such that all biopolymer-stabilized samples mobilized higher UCS values compared to the unamended soil. The optimum dosage was found to be 1.5% for SA, XG and CS, while a notably lower dosage of 0.5% was deemed optimum for GG. Similarly, for a given biopolymer type and dosage, increasing the curing time from 7 d to 28 d further enhanced the UCS, with the achieved improvements being generally more pronounced for XG- and CS-treated cases. None of the investigated biopolymers was able to produce UCS improvements equivalent to those obtained by the 28-d soil–lime samples; however, the optimum XG, GG and CS dosages, particularly after 28 d of curing, were easily able to replicate 7-d lime stabilization outcomes achieved with as high as twice the soil's lime demand. Finally, the fundamental principles of clay chemistry, in conjunction with the soil mechanics framework, were employed to identify and discuss the clay–biopolymer stabilization mechanisms.

The strength and durability properties of the recycled aggregate concrete (RAC) have been affected by the cracks and the weak interfacial transition zone (ITZ) of the recycled coarse aggregates (RCA). However, the mechanical and physical features of RCA can be improved by microbially induced calcite precipitation (MICP). Therefore, immobilization techniques were used to protect and maintain the high efficiency of Bacillus bacteria for the formation and precipitation of calcium carbonates in self‐healing concrete over a period of time. The objective of the present study was to show the viability of the immobilized bacterial consortium‐enhanced RCA to form self‐healing cracks. Further, the self‐healing capability of enhanced RCA was investigated along with two other immobilization methods, that is, RCA and hydrated lime and brick powder (HBr)‐immobilized bacteria. The experimental results show that the increase in the bio‐deposition time improved the physical and mechanical properties of the RCA. Further, subsequently 56 days of the healing incubation period, the immobilized consortium‐enhanced RCA concrete specimens completely healed the cracks of width 0.58 mm. However, the equivalent cracks of width 0.56 mm were also recovered by the HBr immobilized bacterial cultures. Furthermore, the field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and X‐ray diffraction (XRD) analysis revealed that the existence of precipitation at the crack surface was calcium carbonate with a regular cubic‐shaped and lamellar layer morphology. The outcomes of the current study show that consortium‐enhanced RCA has promising potential to develop self‐healing concrete with self‐repaired and improved durability properties in the concrete construction field. [ABSTRACT FROM AUTHOR]

The invasion of the colonial ascidian Didemnum vexillum (Kott, 2002) represents a significant threat to marine ecosystems. In Norway, D. vexillum was recorded for the first time in 2020 and has since continued spreading along the coast. Although the total eradication of this species appears highly unlikely, the implementation of control measures is important to slow down its proliferation and limit the impacts on important species and habitats. In this study, we performed three laboratory experiments, to separately test the effects of lime (fine and coarse quicklime particles and hydrated lime), hydrogen peroxide (H2O2; 0, 1000, 2000 and 4000 mg l-1) and Azamethiphos (0, 50, 100 and 200 µg l-1), on the biofouling cover of D. vexillum. No significant effect of Azamethiphos was detected on D. vexillum cover after 1 hr of exposure, while exposure to H2O2 for 1 hr only reduced its biofouling cover by 50% after exposure to the highest concentration (4000 mg l-1). Conversely, both fine and coarse quicklime particles appeared as suitable control options, reducing the size of the colonies by 100% and 99%, respectively, after exposure for 20 hrs. Additionally, treatment with hydrated lime induced a significant decline in D. vexillum cover by about 89% after 1 hr of exposure. Our results suggest the importance of considering the seasonal variations in environmental conditions and the biology of D. vexillum, to optimize the efficacy of the treatment. Here, we suggest using quicklime and hydrated lime between October and December in the Northern Hemisphere, to benefit from the natural degeneration of D. vexillum during winter and to more effectively eradicate potential remnants that could serve as a basis for regeneration. [ABSTRACT FROM AUTHOR]

The present study explores a cost-effective method for using activated ground granulated blast furnace slag (GGBFS) and silica fume (SF) as cement substitutes. Instead of activating them with expensive alkali solutions, the present study employs industrial-grade powdered sodium aluminate (SA) and hydrated lime (HL) as activators, reducing expenses by about 94.5% compared to their corresponding analytical-grade counterparts. Herein, the exclusivity is depicted using less pure chemicals rather than relying on reagents with 99% purity. Two mixing techniques are compared: one involves directly introducing powdered SA and HL, while the other premixes SA with water before adding it to a dry powder mixture of GGBFS, SF, and HL. Microstructural analysis reveals that the initial strength results from various hydrate phases, including calcium–sodium–aluminate–silicate hydrate. The latter strength is attributed to the coexistence of calcium–silicate hydrate, calcium–aluminate–silicate hydrate, and sodium–aluminate–silicate hydrate, with contributions from calcite and hydrotalcite. The SF content significantly influenced the formation of these gel phases. Thermogravimetric analysis (TGA) reveals phase transitions and bound water related to hydration products. The optimal mix comprises 10% SF, 90% GGBFS, 9.26% HL, and 13.25% SA, with a water-to-solid ratio of 0.45. This approach yields a compressive strength of 35.1 MPa after 28 days and 41.33 MPa after 120 days, hence being suitable for structural construction. [ABSTRACT FROM AUTHOR]

Geopolymers are inorganic polymers obtained through the alkaline activation of aluminosilicates. Due to their cementitious properties, they are being studied as a sustainable alternative to Portland cement. Red ceramic waste (RCW), being a source of silica and alumina, can serve as a precursor for producing geopolymers. In this work, we evaluated the feasibility of producing geopolymers from hollow brick (HB) and hydrated lime, using only sodium hydroxide as an alkaline activator. The test specimens were prepared replacement HB by up to 30 wt% of hydrated lime, aiming to evaluate the compressive strength after 7 and 28 curing days of the geopolymer produced. The results showed that samples with 30 wt% of hydrated lime, achieved the highest compressive strength (11.26 MPa) after 28 days of curing, although all values found were above the limit established by Brazilian standards for modular geopolymer bricks. The results therefore show a sustainable and widely viable implementation alternative to reduce the environmental impacts caused by the production of Portland cement.

Hydrothermal carbonization (HTC) solid and liquid products may inhibit seed germination, necessitating post-treatment. The hydrothermal humification (HTH) method addresses this drawback by transforming inhibitory compounds, such as aromatics, into artificial humic acids (AHAs) and artificial fulvic acids (AFAs). This study introduces a novel approach by investigating the substitution of the commonly used alkaline agent in HTH, KOH, with hydrated lime to develop cost-effective hydrothermal fertilizers from sugar beet pulp, enriching them with AHAs. It assesses the effects of lime on AHA production and soluble organic compounds compared to KOH. The results indicate that lime significantly reduces furans (from 560 to 3.15 mg/kg DM in solid and from 344 to 3.86 mg/L in process liquid) and boosts sugars and organic acids, especially lactic acid (from 4.70 to 65.82 g/kg DM in solid and from 4.05 to 22.89 mg/L in process liquid), increasing hydrochar yield (68.8% with lime vs. 27.4% with KOH). Despite the lower AHA production with lime compared to KOH (3.47% vs. 15.50%), lime-treated hydrothermal products are abundant in calcium and magnesium, boasting a pH of 7. This property presents a safer and more efficient alternative to hydrothermal fertilizers. The characterization of AHAs aligns with standard and natural humic substances, while lime-assisted HTH products, applied at a level of 0.01% w/w, could significantly enhance wheat growth and nutrient uptake compared to the control group. Importantly, these products show no toxicity on Daphnia magna, underscoring their potential for sustainable agriculture.

If asphalt pavements are exposed to cold weather conditions and high humidity for long periods of time, cracking of the pavement is an inevitable consequence. In such cases, it would be a good decision to focus on the filler material, which plays an important role in the performance variation in the hot asphalt mixtures used in the pavement. Although the use of hydrated lime as a filler material in hot asphalt mixtures is a common method frequently recommended to eliminate the adverse effects of low temperature and to keep moisture sensitivity under control in asphalt pavements, the sensitivity of the quantities of the material cannot be ignored. Therefore, in this study, an amount of filler in the mixture was replaced with hydrated lime (HL) filler additive at different rates of 0%, 1%, 2%, 3% and 4%. These asphalt briquettes, designed according to the Marshall method, have optimum asphalt contents for samples with specified HL content. In this study, where the temperature effect was examined at five different levels of −10 °C, −5 °C, 0 °C, 5 °C and 25 °C, the samples were produced in two different groups, conditioned and unconditioned, in order to examine the effect of water. The indirect tensile strength (ITS) test was applied on the produced samples. Experimental study showed that HL additive strengthened the material at low temperatures and made it more resistant to cold weather conditions and humidity. In the second part of the study, two different prediction models with varying configurations were introduced using nonlinear regression and feed-forward neural networks (FFNNs) and the best prediction performance among these was investigated. Examination of the performance measures of the prediction models indicated that ITS can be accurately predicted using both methods. As a result of comparing the developed models with the experimental data, the model provides significant contributions to the evaluation of the relationship between the ITS values obtained with the specified conditioning, temperature changes and HL contents.

Concrete is an important material for the construction of buildings, and highways. However, natural resources are being depleted by using natural coarse or fine aggregates for the production of concrete. The substitution of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) efficiently manages construction waste and preserves natural resources. In the present study, 50 and 100% NCA have been replaced with RCA for the preparation of recycled aggregate concrete (RAC) with blended hydrated-brick powder (RAC-HBr). Additionally, cement was replaced by 10 and 20% of blended HBr in the preparation of RAC mixes. To investigate the strength and durability properties of RCA-HBr mixtures, compressive strength, water permeability, chloride penetration test, and ultrasonic pulse velocity (UPV) tests were conducted. The outcomes indicate that the optimum percentage of blended HBr enhances the compressive strength of RCA mixes. However, blended HBr positively influenced the RCPT, water permeability, and ultrasonic pulse velocity of the RCA concrete mixes. Further, the RCPT outcomes show that the chance of corrosion was reduced by 20%, while the UPV value confirms that the density of the RAC-HBr mixes was enhanced by 28.7% at the age of 56 days. Furthermore, based on the FESEM and EDS analysis, the pozzolanic materials have densified the concrete matrix by reducing the pores and voids of RAC-HBr mixes. Thus, practically, 100% RCA with blended hydrated lime and brick powder can be used to create M35-grade concrete. The current paper investigates the effect of blended HBr on the properties of RAC. 10% HBr was an optimum percentage which has significantly enhanced the strength and durability characteristics of RAC mixes. CSH gel CH crystals densify the concrete matrix. CSH gel and CH crystals were confirmed from the microstructure analysis through FESEM and EDS analysis. [ABSTRACT FROM AUTHOR]

Nowadays, there is an effort to improve the effectiveness of the composting process, supported by the addition of various supplements to reduce soil nutrition losses and increase soil remediation. The aim of this study was to examine the devitalization effect of natural additives like zeolite-clinoptilolite and its combination with hydrated lime in composted cattle manure on indicator and pathogen bacteria. The composting process was running in three static piles of cattle manure mixed with wheat straw (control, zeolite–lime, and zeolite) for 126 days. Composted manure substrates were determined for physicochemical (temperature, pH, nitrogen and phosphorus content, C/N, organic matter, and moisture) and microbiological analyses (Salmonella spp., indicator bacteria). The effects of additives were reflected in changes in physicochemical factors, e.g., an increase in temperature (<53 °C) or pH (<9.3). According to Pearson correlation, these changes (pH, Nt, Pt) resulted in a significant decrease (p < 0.001) of indicator bacteria (two or three orders) in zeolite pile or zeolite–lime pile. Die-off of Salmonella spp. in the zeolite–lime pile was indicated within 41 days; in other piles, this occurred on day 63. Our results can aid in further optimizing the composting of cattle manure in order to lower environmental pollution and the risk of human infection. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

In recent years, magnesium oxide (MgO) has been considered by researchers as a new agent for the remediation of contaminated soils. In this paper, the effect of MgO and hydrated lime on the remediation of a clay soil contaminated with MTBE (Methyl Butyl Ether) was studied. The contaminated soil was made artificially by adding 2.25 g MTBE per kg of soil. MgO with different percentages (0.125, 0.25, 0.5, 5, 10, and 20%) and lime with 2.5, 5, and 10% percentages were added to the natural and contaminated soil. The results showed that by increasing the percentage of MgO or lime and curing time, the strength of natural and contaminated soil was improved. The results of the leaching tests showed that by adding 5, 10, or 20% MgO, all the existing MTBE in the soil samples were removed while for the smaller percentages of MgO (0.125, 0.25, and 0.5%) there was a decrease in the concentration of MTBE with time. The results of the leaching tests also revealed that the hydrated lime was effective in reducing the concentration of MTBE. The amount of reduction in the concentration of MTBE was dependent on the percentage of MgO or hydrated lime. The comparison of the results of the two binders showed that MgO was more effective than the hydrated lime in removing the MTBE from the soil. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) solid and liquid products may inhibit seed germination, necessitating post-treatment. The hydrothermal humification (HTH) method addresses this drawback by transforming inhibitory compounds, such as aromatics, into artificial humic acids (AHAs) and artificial fulvic acids (AFAs). This study introduces a novel approach by investigating the substitution of the commonly used alkaline agent in HTH, KOH, with hydrated lime to develop cost-effective hydrothermal fertilizers from sugar beet pulp, enriching them with AHAs. It assesses the effects of lime on AHA production and soluble organic compounds compared to KOH. The results indicate that lime significantly reduces furans (from 560 to 3.15 mg/kg DM in solid and from 344 to 3.86 mg/L in process liquid) and boosts sugars and organic acids, especially lactic acid (from 4.70 to 65.82 g/kg DM in solid and from 4.05 to 22.89 mg/L in process liquid), increasing hydrochar yield (68.8% with lime vs. 27.4% with KOH). Despite the lower AHA production with lime compared to KOH (3.47% vs. 15.50%), lime-treated hydrothermal products are abundant in calcium and magnesium, boasting a pH of 7. This property presents a safer and more efficient alternative to hydrothermal fertilizers. The characterization of AHAs aligns with standard and natural humic substances, while lime-assisted HTH products, applied at a level of 0.01% w/w, could significantly enhance wheat growth and nutrient uptake compared to the control group. Importantly, these products show no toxicity on Daphnia magna, underscoring their potential for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Fluorogypsum was the waste residue emitted during the production of dry-process aluminum fluoride or wet-process hydrogen fluoride. Its main component was CaSO4. In order to comprehensively utilize the fluorogypsum, this study used hydrated lime and rapid carbonation curing to enhance the compressive strength and softening coefficient of the fluorogypsum. The characteristics of the composite material system after hardening at different proportions of fluorogypsum and hydrated lime, as well as different water to material ratios, were analyzed using DTA-TG, XRD, and SEM-EDS. The research results showed that when the water to material ratio was 0.1, with the increase of hydrated lime content, the compressive strength of the composite material increased from the original (without hydrated lime) 2.4 MPa to 22.4 MPa. The test results of XRD, DTA-TG, and SEM-EDS showed that the reaction products of the composite material were gypsum dihydrate and calcium carbonate, and the content of calcium carbonate was relatively higher when the hydrated lime content was 50% and 70%. Under the synergistic effect of hydrated lime activation and rapid carbonation curing, the mechanical strength and water resistance of the fluorogypsum were improved, which has significant guiding significance for the production and research of gypsum-based building materials. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of subgrade soil stabilization on the performance and life extension of flexible pavements. Several variables affecting soil stabilization were considered, including subgrade soil type (CL or CH), additive type and content (3, 6, and 9% of hydrated lime, 5, 10, and 15% of class C fly ash (CFA), and 5, 10, and 15% of cement kiln dust (CKD)), three stabilization thicknesses (15, 30, and 45 cm), and four pavement sections with varying thicknesses. The effects of these variables were investigated using four different damage mechanisms, including the fatigue life of the asphalt concrete (AC) and stabilized subgrade layers, the crushing life of the stabilized subgrade soil, and the rutting life of the pavement, using a non-linear mechanistic-empirical methodology. The results suggest that the optimum percentage that maximizes the pavement life occurs at 3% of lime for subgrade soil type CL, 6% of lime for subgrade type CH, and 15% of CFA and CKD for both subgrade soil types. The maximum pavement life increase occurred in the section with the lowest thickness and the highest stabilization thickness, which was 1890% for 3% of lime in the CL subgrade and 568% for 6% of lime in the CH subgrade. The maximum increase in the pavement life of subgrade stabilization with 15% of CFA was 2048% in a CL subgrade, and 397% in a CH subgrade, and life extension due to subgrade stabilization with 15% of CKD was 2323% in a CL subgrade and 797% in a CH subgrade. [ABSTRACT FROM AUTHOR]

The physical and mechanical behavior of experimental mixtures with additions of cassava starch, carboxymethyl cellulose, and hydrated lime in a clay matrix is described. The added elements accounted for 3% of the weight of the mixes and the clay matrix for 97%. Mixing water was incorporated in different % according to the workability and molding of the mixes. Tests indicated the influence of additions on volumetric changes, particle detachment, and mechanical strength of the experimental mixtures. It was concluded that percentages ≥ 50% carboxymethylcellulose favored properties in mixtures. The opposite result was obtained with the addition of lime. Mixtures with additions of 25% cassava starch and 75% carboxymethylcellulose reported similar mechanical behavior and no particle detachment.

Aggregate holds the main role in determining the quality of pavement layers. Unfortunately, the locally available aggregates sometimes did not pass one or more requirements stated in the standard, making these aggregates technically unable to be used. These aggregates are called marginal or substandard aggregates. However, previous research projects have shown the potential of utilizing marginal aggregates as pavement layers. This research aims to analyst the techniques for utilizing marginal aggregates as pavement layers, specifically as subbases. Two techniques were evaluated herein, namely by varying the aggregate gradation and by adding cement and lime as stabilizers, and the specimens were assessed by the California Bearing Ratio (CBR) test. The research results found that varying the percentage of coarse and fine aggregates in the specimens improved the CBR value. The specimen obtained the highest CBR value with 70% coarse aggregate and 30% fine aggregate. Moreover, it was found that adding cement and lime as stabilizers at the right percentage was also able to improve the CBR value of the specimens and mixing the stabilizers beyond a certain percentage decreases the CBR value. The amount of cement and lime needed depended on the aggregate gradation used.

Chemical stabilization is used to enhance and increase the strength characteristics of soft and problematic soils. In this research, Gaussian Process Regression (GPR) is employed to estimate the unconfined compressive strength (UCS) and the Young’s modulus (E) of lean clay soils stabilized with iron ore mine tailing (IOMT) and hydrated lime (HL) percentage. In this regard, four inputs including the moisture content (MC), IMOT percentage, HL percentage, and curing time (CT) were used. The value of R2 for estimating the UCS and the E were 0.9825 and 0.9633 for all data, respectively. The RMSE for predicting the UCS and the E were 0.1875 and 19.868 for all data, respectively. The result of the sensitivity analysis demonstrated that MC, CT, HL, and IOMT percentage have the highest contribution to the UCS of the stabilized lean clay, respectively. Also, MC, HL, IOMT percentage, and CT have the highest impact on the E of the stabilized lean clay, respectively. The parametric study also revealed that increasing the HL content and the curing time led to an increase in the UCS and the E of stabilized lean clay, while IOMT content and the moisture content has an inverse relationship with the UCS and the E of stabilized lean clay soils.

Geotechnical engineering relies heavily on predicting soil strength to ensure safe and efficient construction projects. This paper presents a study on the accurate prediction of soil strength properties, focusing on hydrated-lime activated rice husk ash (HARHA) treated soil. To achieve precise predictions, the researchers employed two grey-box machine learning models—classification and regression trees (CART) and genetic programming (GP). These models introduce innovative equations and trees that readers can readily apply to new databases. The models were trained and tested using a comprehensive laboratory database consisting of seven input parameters and three output variables. The results indicate that both the proposed CART trees and GP equations exhibited excellent predictive capabilities across all three output variables—California bearing ratio (CBR), unconfined compressive strength (UCS), and resistance value (Rvalue) (according to the in-situ cone penetrometer test). The GP proposed equations, in particular, demonstrated a superior performance in predicting the UCS and Rvalue parameters, while remaining comparable to CART in predicting the CBR. This research highlights the potential of integrating grey-box machine learning models with geotechnical engineering, providing valuable insights to enhance decision-making processes and safety measures in future infrastructural development projects.

Premature failure in asphalt concrete pavement has been the main concern for pavement construction companies and engineers in recent years because of the large rise in traffic volume and loads and the temperature extremes in the summer and winter. The use of modifiers in asphalt concrete mixtures has attracted much attention to increase the performance and lifespan of pavements. As nanotechnology developed, several researchers concentrated on how these materials can help increase pavement serviceability by minimizing rutting and moisture damage. This study evaluates the Hydrated Lime (HL) effect by two methods (wet and dry hydrated lime) on the durability of the warm mix asphalt. The first method, HL, has been supplemented to the asphalt binder with three ratios (0.5%, 1%, and 1.5%) by weight of asphalt (Wet HL). Then, the second method was added via the aggregate weight as a replacement filler using three percentages (1%, 2%, and 3%) (Dry HL). The mechanical qualities, including Marshall Mix design, moisture susceptibility, and permanent deformation, were evaluated through experimental tests. Results showed that the mechanical characteristics and the fineness of the HL particle sizes are positively correlated.

Waste engine oil, a by-product of engine wear and tear, is annually discarded in environmentally harmful ways. Prior modifications of asphalt binder with waste engine oil resulted in lower consistency, reduced moisture damage resistance, and impaired high-temperature performance. To address these issues, three additives--Elvaloy, Eaton's Reagent (ER), and hydrated lime (H-L) were used to enhance waste engine oil-modified bitumen in the asphalt mixture. This modified bitumen underwent tests for binder and mixture like Softening point, Penetration and Marshall stability test. The findings show that both Waste Engine Oil (WEO) and Hydrated Lime (HL) can impact the Marshall stability of asphalt mixtures. The introduction of 2% Waste Engine Oil (WEO) leads to a 0.66% decrease in the stability of the asphalt mixture, while stability experiences a more significant reduction of 25.21% with the inclusion of 6% WEO. On the other hand, the addition of HL results in a significant 6.1% increase in stability; nevertheless, the addition of additional HL may cause the stability to decline. The introduction of Elvaloy resulted in a notable increase in stability, with a 2.5% incline. In the same way, Eaton's Reagent shows a significant effect, leading to a noteworthy 7.2% increase in stability in the asphalt mixture. These results emphasize the overall effectiveness of binder modification with waste engine oil when combined with suitable additives. [ABSTRACT FROM AUTHOR]

Brown film formation, a unique developmental stage in the life cycle of Lentinula edodes, is essential for the subsequent development of fruiting bodies in L. edodes cultivation. The pH of mushroom growth substrates are usually adjusted with hydrated lime, yet the effects of hydrated lime on cultivating L. edodes and the molecular mechanisms associated with the effects have not been studied systemically. We cultivated L. edodes on substrates supplemented with 0% (CK), 1% (T1), 3% (T2), and 5% (T3) hydrated lime (Ca (OH)2), and applied transcriptomics and qRT-PCR to study gene expression on the brown film formation stage. Hydrated lime increased polysaccharide contents in L. edodes, especially in T2, where the 5.3% polysaccharide content was approximately 1.5 times higher than in the CK. The addition of hydrated lime in the substrate promoted laccase, lignin peroxidase and manganese peroxidase activities, implying that hydrated lime improved the ability of L. edodes to decompose lignin and provide nutrition for its growth and development. Among the annotated 9,913 genes, compared to the control, 47 genes were up-regulated and 52 genes down-regulated in T1; 73 genes were up-regulated and 44 were down-regulated in T2; and 125 genes were up-regulated and 65 genes were down-regulated in T3. Differentially expressed genes (DEGs) were enriched in the amino acid metabolism, lipid metabolism and carbohydrate metabolism related pathways. The carbohydrate-active enzyme genes up-regulated in the hydrated lime treatments were mostly glycosyl hydrolase genes. The results will facilitate future optimization of L. edodes cultivation techniques and possibly shortening the production cycle. [ABSTRACT FROM AUTHOR]

Annually tons of waste engine oil is wasted or dumped in environmentally unfriendly ways. Asphalt binder has been modified with waste engine oil previously and showed, lower consistency, lower moisture damage resistance at higher dosages, and impaired high-temperature performance. In the current study, three different additives were added to solve these issues associated with waste engine oil-modified bitumen. Elvaloy, polyphosphoric acid (PPA), and hydrated lime (H-L) were used as polymer, chemical, and filler-type additives. Waste engine oil-modified bitumen combined with all three types of additives was evaluated using conventional viscosity, moisture susceptibility, dynamic mechanical, and chemical testing. Results showed that waste engine oil inclusion decreased the consistency of binder, reduced viscosity, and impaired high-temperature performance. Elvaloy's addition to waste engine oil-modified bitumen made it less sensitive to temperature changes, increased the performance grade, improved the stiffness, and enhanced the resistance against rutting and moisture-induced damages. Polyphosphoric acid addition refined the consistency of binder modified with waste engine oil. It drastically increased the complex modulus values and decreased phase angle values by stiffening the binder. PPA enhanced the moisture susceptibility of asphalt and improved its high-temperature performance. Hydrated lime improved moisture resistance and bonding strength but showed less effectiveness in improving high-temperature performance at lower dosages. The results conclude that binder modification with waste engine oil can be effective with other additives like polyphosphoric acid, Elvaloy, and hydrated lime. [ABSTRACT FROM AUTHOR]