Papers by Keyword: Lime

Abstract: This study is about a church built at the end of the 19th century, made of burnt brick and lime mortar with sand, inadequately renovated. The objective of the study is to signal about the damages suffered by the old buildings due to the use of inadequate materials in repair. The present building was less than 20 years ago renovated by replacing the old lime-sand plaster with cement mortar, a fact that led to the accumulation of moisture in masonry, resulting the damage of the finishes and affecting the safe health conditions. The article presents temperature, humidity and dew point measurements, a calculation of the comfort index, and a software modelling, as well as the correct solutions.

Abstract: The use of out-of-furnace desulphurization of cast iron and various dispersed desulfurizing reagents is due to the desire to ensure the most complete removal of cast iron sulfur in the shortest period of time. The actual results of the industrial application of out-of-furnace desulfurization indicate that the practical results and application rates in a number of cases are not stable enough and are far from possible and expected. The studies were carried out on calculated and "cold" transparent physical models. Magnesium, lime, and calcium carbide were evaluated as desulfurizing reagents. Based on the actual results of physical modeling and subsequent calculations, an improved expression was formulated for determining the length of a gas jet in a liquid (L_str ) - the depth of the jet immersion, depending on the parameters of injection through a submerged lance. The processes of interaction between gas and solid phases in the near-lance zone during ladle desulphurization have been studied. It is shown that during the injection desulfurization of cast iron, the gas component of the flow stops its directional movement in the melt for up to 80 mm (practically 50–60 mm), solid particles continue to move in the bubble and hit the surface of this cavity. To assess the further movement of the particle through the "gas cavity-melt" boundary, the depth of penetration of particles into liquid iron was calculated. The motion of a particle in a melt can be described by an equation that is arranged for the conditions of vertical motion of a particle from top to bottom with a given initial velocity up to the complete stop of the particle. Nomograms are given to determine the specified parameters. Recommendations are given on the parameters of injection of magnesium and ground lime.

Abstract: The aim of this study was to investigate the feasibility of manufacturing typha-based materials with a lime-based binder. For this purpose, three types of lime with different compositions were tested to produce lime-based typha concretes. The mechanical performance (compressive strength and apparent modulus of elasticity) of the materials developed was evaluated as a function of binder content and binder type. Two types of formulations were studied: one with a binder/aggregate ratio of 3, called F3, and the other with a binder/aggregate ratio of 2, called F2. Water absorption kinetics and typha particle size analysis were also studied. The dry density, compressive strength and apparent modulus of elasticity of typha concretes were determined. The results showed a reduction of mechanical performance as the binder/aggregate ratio decreased. The density of typha concretes range from 520 kg/m3to 396 kg/m3. The best mechanical performances were obtained with Thermo Tradical and Earasy binders. When the binder/aggregate ratio was reduced from 3 to 2, stress at 10% strain ranged from 0.6 MPa to 012 MPa and apparent modulus of elasticity from 31.5 MPa to 3.57 MPa. This study showed that binder composition has a significant impact on the mechanical performance of plant-based concretes.

Abstract: Many factors influence the effectiveness of traditional binders used for soil stabilization, including anions present in the soil and carbonates. Natural pozzolana-lime stabilization is a relatively new technique that has shown promising results. However, no study has specifically evaluated its success in the presence of phosphate for high-carbonate soils. This paper investigates this question using marly soil from Medea, which was pre-contaminated with the common fertilizer monoammonium phosphate at 0, 2, 4, and 6% by dry weight, then stabilized with lime and/or natural pozzolana at 0, 8%, and 20%, respectively, by dry weight. To assess the effect of phosphate, mineralogical and macrostructural changes in these mixtures were analyzed through X-ray diffraction tests and scanning electron microscopy, respectively. Additionally, pH levels were monitored over 90 days, and changes in Atterberg limits between 1 and 30 days of curing were compared. Variations in immediate bearing indexes and compaction parameters were also examined. The study found that lime alone was ineffective in stabilizing the soil due to high carbonate content, with improvements in geotechnical properties only observed when natural pozzolana was added with lime. Phosphate was found to impact the lime-natural pozzolana stabilization technique significantly.

Abstract: The article provides information about the initial elements in the waste and tailings of the copper processing plant of the Almalyk Mining and Metallurgical Combine and theoretical solutions for the extraction of metals. According to chemical data, the amount of iron in the waste is high (52.6%), and the most effective solution for extracting iron from the waste is the reduction process. An increase in the amount of iron to 88.9% was formed using coal and lime as reducing agents.

Abstract: Direct reuse of precast concrete elements is possible if disassembly is considered in the design phase. An unusual way of designing for disassembly is to use “wet” joints as usual but to optimise the mortar to be less strong and, therefore, easier to remove at the end of the life of the building. A method is presented to test mortars with lime content to determine the shear capacity in the connection between mortar and concrete. Tests are performed with and without an applied normal force and with and without steel bars through the interface. The results show that applying a lime content to the mortar reduces the compressive strength, shear strength and flexural strength. Using steel bars in the connections increases the ductility from less than 1 mm to several mm at the point of failure. The results can be used in future checks of mortar joints in buildings, where it is required to have a minimum strength during the service life and a maximum strength when dismantling. The future mortar requirements will depend on the disassembly method.

Abstract: Soil contamination by heavy metals significantly damages the environment, human health, plants, and animals, which has become a burning issue recently. The presence of contaminated soils due to industrials and mining activities is a major concern in today’s heavily industrialized world. With the rapid development of society, more and more soils are polluted by heavy metals, which leads to a change in soil engineering properties. Several types of technology have long been in use to remedy the heavy metal-contaminated soil. Among them, solidification and stabilization have been widely adopted. In engineering practice, engineers usually use additives to solidify and stabilize (s/s) heavy metal-contaminated soils. Solidification and Stabilization is an economic and effective technology in the remediation of contaminated soil by heavy metals, as well as sludge and sediment. The main purpose of the study was to investigate the effect of (nanomaterial materials) on the remediation of contaminated soil by the (S/S) technique. The soil was polluted with (2000 mg/kg and 1000 mg/kg) of Lead and Cadmium respectively by using Lead and Cadmium nitrates. The Pb and Cd- impacted soil was remediation using rich silicon materials of (nano-silica ) as an alternative cementitious material, and replaced with contaminated soil at (3, 5, and 7%) respectively with (5% and 10%) Lime. Nanosilica was prepared from plant extracts. The binder performance was analyzed by using unconfined compressive strength ( UCS) on the solidified soil at three curing times which were 7, 14, and 28 days. TCLP was also applied to investigate the treatment degree of solidified soil for the specimens within 28 days. The result of (UCS) indicated development in strength with curing day for all binders and proved that all mix ratios exceed the minimum Criteria of landfill disposal which is 340 kPa (0.34 N/mm2). It also showed increases in strength with using nano-silica with a lime binder. The result of the leaching test for the stabilized soil after 28 days of curing, showed a reduction in lead and cadmium leaching rate for all binders, below the EPA lead leachability limit of 5 mg/l and cadmium 1 mg/l. The results showed that the sample SH2N5L10 after 28 days is the best percentage for decreasing the leaching rate of lead and cadmium, as it reached (1.4 mg /l and 0.012 mg/l) respectively with the highest compressive strength of 4852 Kpa.

Abstract: The burning process of limestones is an important process in the modern industries, which can be described in two parts, CaCO₃ decarbonation due to the thermal stress and formation of CaO crystalline structure. It was already observed that the different composition and structure of a raw material influence the transformation process and has affect on the chemical and mechanical properties on the formed lime. This study is focused on the characterization of the raw material (porosity, chemical composition, geological age and origin) and its effect on the burning process and the formation of CaO and its properties. The microstructure of studied material burnt at different times of isothermal load was observed by SEM and the reactivity test was measured and analyzed. The limestone with a more porous inner system was burnt faster and is inclinable to overburn at longer thermal load.

Abstract: The article presents the physical, mechanical (strength, density), and chemicalcharacteristics of complex M100 water-resistant mortar compositions, which include crushedlimestone (0.16–1.25 mm) and granite-crushed sand. Additionally, stone masonry mortar mixtureswith a grain size of up to 5 mm have been developed using local raw materials for the restoration ofwall constructions in building structures.The relationship between the density and chemical stabilityof the hardened samples was determined using the results of complex research on the structuringprocess of the test samples obtained with the modifiers used to improve the workability of theprocessed lime mortars.

Abstract: Steelmaking industry generates a large volume of by-products that not always can be reintroduced into production processes, such as the steelmaking process itself or the production of cement. This is the case of ladle furnace slag (LFS), whose potential use is limited and usually ends up in landfill. This work investigates the feasibility of using LFS as binder for clayey soils stabilization in substitution of lime. The main parameters evaluated are plasticity index, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS). The results show that the strength behavior of the mixtures is remarkable, obtaining increases in the CBR index between 8-14 times above unmodified clays. The mechanical performance base on UCS results show improvements of 85 % relative to natural soils three days after mixing. Moreover, if the curing time is up to 90 days, the UCS doubles or triples its value. Depending on the chemical composition of the soils, the performances of the mixtures are different, but in all cases the results are positive and encourage further research for the incorporation of ladle furnace slag as stabilizing agent.