Showing papers on "Lime published in 2018"
TL;DR: The combination of soil washing and in situ immobilization is an effective method to amend the soils contaminated with multiple heavy metals and lime was the most effective material, indicating that low soil pH and high acid-soluble metal concentrations might restrain the activity of soil enzymes.
178 citations
TL;DR: In this paper, the authors focus on the problems associated with soil failure that occur during the construction and widening of roads and highways in the area of interest, and demonstrate that satisfactory strength can be achieved with the addition of 5% additives to the soil mixture.
109 citations
TL;DR: In this paper, the sustainability of incorporating pulp and paper waste sludge into concrete-based mortars was analyzed, and the results showed that for use in wall and ceiling mortar coatings, the level of incorporation should not exceed 10%, because higher levels yield lower values of mechanical strength resistance, incompatible with market requirements.
99 citations
TL;DR: In this article, the calcinated coal gangue was mixed with granulated blast furnace slag and slaked lime in making geopolymer based on increasing calcium content to improve the strength.
98 citations
TL;DR: This study aimed to co-compost Chinese medicinal herbal residues (CMHRs) as the bulking agent with food waste (FW) to develop a high value antipathogenic compost and recommended use of CMHRs as the bulk weight to compost food waste at the dry weight ratio of 1:1:1.
94 citations
TL;DR: Investigation of the effects of hydrated lime, hydroxyapatite, organic fertilizer and organic fertilizer alone or in combination to remedy Cd contaminated agricultural soil under rice-wheat rotation showed that crops grain yield, Cd concentration, soil pH, CaCl2 extractable Cd and Cd speciation were markedly affected by the amendments.
94 citations
TL;DR: Surprisingly, miscanthus biochar, by itself, was limited at mitigation, but when combined with lime, the combination was capable of further reducing extractable metal concentrations and improving β-glucosidase enzyme activity.
91 citations
TL;DR: In this article, the pore structure of air lime mortars, formulated with aggregates of different mineralogy and grain size distribution, was evaluated with the aim of studying the influence of sand type on the microstructural modification over time and of establishing the relationship between these modifications and the mechanical behaviour.
81 citations
TL;DR: This study investigates the suitability of seven different waste materials as fillers in place of conventional material in dense graded bituminous macadam mix and finds that all waste modified mixes delivered satisfactory mechanical and volumetric performances as demanded by paving specifications.
80 citations
TL;DR: The investigated red mud and arsenic sludge can be successfully utilized in cement composites to create a red mud-based cementitious material.
79 citations
TL;DR: In this paper, the use of fly ash (FA) and slag (S) as alternative green binders in ground-improvement projects that would reduce the carbon footprint of these projects was investigated.
TL;DR: In this article, the use of alkaline waste material from the alumina refining industry (Bayer liquor and precipitates formed by the seawater neutralisation of Bayer liquor), for the neutralization of acid mine drainage (AMD) water was reported.
Abstract: This study reports the novel use of alkaline waste material from the alumina refining industry (Bayer liquor and precipitates formed by the seawater neutralisation of Bayer liquor), for the neutralisation of acid mine drainage (AMD) water. The hypothesis was that utilization of waste to treat waste can potentially result in environmental and economic benefits. The performance of Bayer liquor and Bayer precipitate was compared with conventional alkalis used for AMD neutralisation such as lime (Ca(OH)2), sodium hydroxide (NaOH), and sodium carbonate (Na2CO3). Target ions to remove from the AMD solution included Al (1233 mg/L), Cu (77.26 mg/L), Fe (16.7 mg/L), Ni (1.54 mg/L), Mn (161.5 mg/L) and Zn (48.89 mg/L)). Both alumina industry wastes were shown to produce treated water with acceptable discharge limits for all metals except Mn. Nevertheless, Bayer precipitate was shown to have an enhanced ability to remove manganese at lower pH (6.5–7.5) relative to lime, with residual Mn concentrations of 32.30 and 85.40 mg/L, respectively. Manganese discharge limits were challenging to meet due to pH values >9 being required wherein not only aluminium species redissolved but also the pH was not compatible with discharge regulations. Mechanistically, larger precipitates were found to positively influence the removal of heavy metals, with lime and Bayer precipitates forming the largest precipitates. Overall, Bayer precipitate was found to be a potential alternative for the treatment of AMD water.
TL;DR: In this article, the effectiveness of biochar added to this contaminated soil using compost, peat or lime as a reference was evaluated and the combined effect of pH and metal complexation capacity of added biochar resulted in an effective reduction in soluble Cd concentrations that lasted longer than when lime, compost or peat are used.
TL;DR: A simple method to preliminarily estimate the immobilization efficiency of amendments and predict their stability in acid rain regions before large-scale field application is provided.
TL;DR: Very few studies have been carried out to investigate the durability and swelling behavior of dredged marine materials as discussed by the authors, and this study mainly considers the influence of seawater conditions on the performance of marine materials.
Abstract: Very few studies have been carried out to investigate the durability and swelling behavior of dredged marine materials. To tackle this issue, this study mainly considers the influence of wa...
TL;DR: In this article, the authors evaluated the influence of the stabilizers on the physical-mechanical properties of black cotton soils (BCSs) and found that the use of combinations of lime and natural volcanic ash (VA) improved the performance of BCS.
Abstract: Lime treatment of loess in foundation engineering modifies the soil structure, leading to changes in mechanical and hydraulic properties of soil, which in turn will affect the flow of water and transport of contaminants in the loess. In light of this, it is essential to identify the dominant effects of different lime treatments on hydraulic conductivity, and to ascertain the optimum lime treatment. For this purpose, we investigated the effects of dry density and lime content on changes in hydraulic conductivity and microstructure of loess in Yan’an City, China. The results indicate that hydraulic conductivity has a log negative correlation with dry density, and lime addition can result in a decrease of hydraulic conductivity of loess at the same dry density. Under a given degree of compaction, however, lime addition can lead to a decrease in dry density due to an increase in flocculation and aggregations. The significant decrease of dry density leads to an increase in hydraulic conductivity when lime content (in mass percentage) is lower than 3%. Nevertheless, when lime content is higher than 3%, the reactions between loess particles and lime will be intensified with an increase in lime content, and become the primary factors affecting pore characteristics. These reactions can further decrease the hydraulic conductivity of lime-treated loess, and the lowest hydraulic conductivity was obtained for lime-treated loess with 9% lime content. The excess lime (above 9% lime content) dramatically increased pore size, leading to a significant increase in hydraulic conductivity. Therefore, 9% is the optimum lime content for loess treatment, and the degree of compaction in engineering should be higher than 95%. In addition, statistical analysis of microstructure of lime-treated loess shows that the distribution trends of macro- and meso-pores coincided with that of saturated hydraulic conductivity, which indicates that lime content affects saturated hydraulic conductivity of lime-treated loess by changing the soil structure, especially the properties of pores larger than 8 µm.
TL;DR: In this paper, a comparison of influences of freeze-thaw action on lime stabilized basalt and polypropylene fiber reinforced clay was investigated, and a linear correlation was observed between unconfined compressive strength and ultrasonic pulse velocity values.
TL;DR: In this article, the macro and micro properties of natural hydraulic lime (NHL2 and NHL5) mortars, white Portland cement-aerial lime-based (CL15 and CL25), and slagaerial leavened (SL20 and SL40), were studied through an examination of their physical and mechanical properties, environmental resistance properties, hardening mechanism and microstructure of lime mortars or pastes.
TL;DR: Lime addition as well as formation of struvite through the addition of magnesium and phosphorus salts provide good pH buffering and may reduce odour emission and improve the variation of total bacteria, which in turn increased the organic decomposition.
TL;DR: Results indicated that molasses pellets and molasses/lime pellets exhibited increased compressive strength, density, and impact resistance due to the "solid bridge" that formed from molasses recrystallization and agglomeration by lime.
TL;DR: In this article, a new eco-material based on date palm fiber and lime is presented, which has the ability to absorb water vapor in a high relative humidity environment and to restore it in a dry one.
TL;DR: In this article, the effects of mineral reaction on the transference of copper and zinc during sludge combustion are investigated, and it is suggested that through reactions with aluminosilicate, calcium changes heavy metals transference to a different extent.
TL;DR: In this paper, the main objective of the study is to make use of the rice husk ash and lime powder (LP) as a replacement of Portland pozzolana cement considering various replacement levels.
Abstract: Industrial wastes and recycled materials are being utilized in the construction industry for preserving the environment, saving of materials, and enhancing durability of the construction material. Blending of cement with supplementary cementitious materials like fly ash, rice husk ash, and silica fume makes concrete more durable. The main objective of this study is to make use of the rice husk ash and lime powder (LP) as a replacement of Portland pozzolana cement considering various replacement levels. The engineering and durability performance in concrete with LP were performed through compressive strength and void measurement. The microstructure in the concrete with LP was characterized through XRD, SEM/EDS, and TG/DTA. Optimum replacement ratio for rice husk ash and LP were obtained through pozzolanic reaction based CSH formation.
TL;DR: In this paper, the potential of chicken eggshell waste to produce calcitic lime was explored, and the results showed that the most reactive class of calcium oxides from eggshells was R5-60°C within 10min, the same as that of calcium oxide from limestone.
Abstract: Eggshells wastes are produced in huge amounts worldwide. The recycling or valorization of this waste, which otherwise is usually disposed in landfills, represents an opportunity within a circular economy perspective. In the present work, the potential of chicken eggshell waste to produce calcitic lime was explored. After collection from an industry supplier, the waste was thoroughly characterized for its mineralogical, chemical, and thermal properties. The material was calcined at 1000 °C, and the obtained calcium oxide was evaluated for its reactivity in wet slaking tests. Comparison was made with commercial limestone used as reference. It was found that the calcium oxide from eggshell waste belonged to the most reactive class (R5—60 °C within 10 min), the same of the calcium oxide from limestone. However, different times were obtained to reach 60 °C (25 s and 4:37 min:s) and for 80% of the reaction (28 s and 5 min) for calcium oxide from limestone and eggshell waste, respectively. The lower reactivity of calcium oxide from eggshell waste was related to its larger size particles with smoother surfaces and lower specific surface area in comparison to limestone calcium oxide. Industrial, environmental and economic implications concerning the use of this waste to produce lime were also evaluated. The eggshell waste could be all consumed at an industrial scale in Portugal allowing for approximately 2.6% partial substitution of limestone in a lime factory.
TL;DR: In this paper, a lime-based low carbon cementitious material (LCM) was designed and prepared using low contents of hydrated lime and Portland cement and a high content of mineral admixtures.
TL;DR: In this paper, the effects of thermal treatment on the reactivity of the tailings and the use of different activating solutions on the physical properties, microstructure and leaching of harmful components are reported.
Abstract: Gold mining produces hazardous tailings wastes with elevated sulfur content and high levels of heavy metals including oxyanion elements such as V and As. This research investigated activation of these tailings with calcium hydroxide and sodium hydroxide/sodium silicate as a way to stabilize the material and limit leaching of harmful components. The effects of thermal treatment on the reactivity of the tailings and the use of different activating solutions on the physical properties, microstructure and leaching of harmful components are reported. The effect of adding ground granulated blast furnace slag to the tailings is also assessed. The use of 5 wt % Ca(OH)2 activating solution produces optimum performance increasing the immobilization efficiency of sulfates, arsenic and the other harmful elements. Heat-treating mine tailings at 900 °C slightly improves the reactivity but did not improved the immobilization efficiency. Microstructural analysis by TEM and XRD confirmed that stabilization is based on calcium sulfate and/or ettringite formation during alkali-activation. All materials achieved reasonable compressive strength after 28 days of curing and the potential for using alkali activation as a method to treat tailings from mining is discussed.
TL;DR: In this paper, the impacts of surface lime re-application at different rates and splitting rates on the amelioration of soil acidity and its distribution and migration through soil profile in a sandy Ultisol from Southern Brazil under long-term no-tillage (NT) system were investigated.
TL;DR: The results indicated that continuous flooding was a reasonable water management candidate coupled with lime addition for immobilizing soil Cd and drying-wetting cycles and N fertilizer addition may enhance soil Cc release.
TL;DR: In this article, secondary steel slag (SSS) was used a potential material in subgrade treatment, and the results showed that the reconstitution and activation of SSS is an effective way to improve the performance in sub grade treatment.